Publications by authors named "Satyanarayana Somavarapu"

52 Publications

Micellar Nanocarriers of Hydroxytyrosol Are Protective against Parkinson's Related Oxidative Stress in an In Vitro hCMEC/D3-SH-SY5Y Co-Culture System.

Antioxidants (Basel) 2021 May 31;10(6). Epub 2021 May 31.

Centre for Nutraceuticals, School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.

Hydroxytyrosol (HT) is a natural phenolic antioxidant which has neuroprotective effects in models of Parkinson's disease (PD). Due to issues such as rapid metabolism, HT is unlikely to reach the brain at therapeutic concentrations required for a clinical effect. We have previously developed micellar nanocarriers from Pluronic F68 (P68) and dequalinium (DQA) which have suitable characteristics for brain delivery of antioxidants and iron chelators. The aim of this study was to utilise the P68 + DQA nanocarriers for HT alone, or in combination with the iron chelator deferoxamine (DFO), and assess their physical characteristics and ability to pass the blood-brain barrier and protect against rotenone in a cellular hCMEC/D3-SH-SY5Y co-culture system. Both HT and HT + DFO formulations were less than 170 nm in size and demonstrated high encapsulation efficiencies (up to 97%). P68 + DQA nanoformulation enhanced the mean blood-brain barrier (BBB) passage of HT by 50% ( < 0.0001, = 6). This resulted in increased protection against rotenone induced cytotoxicity and oxidative stress by up to 12% and 9%, respectively, compared to the corresponding free drug treatments ( < 0.01, = 6). This study demonstrates for the first time the incorporation of HT and HT + DFO into P68 + DQA nanocarriers and successful delivery of these nanocarriers across a BBB model to protect against PD-related oxidative stress. These nanocarriers warrant further investigation to evaluate whether this enhanced neuroprotection is exhibited in in vivo PD models.
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http://dx.doi.org/10.3390/antiox10060887DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8226543PMC
May 2021

Higher throughput drug screening for rare respiratory diseases: Readthrough therapy in primary ciliary dyskinesia.

Eur Respir J 2021 Apr 1. Epub 2021 Apr 1.

Respiratory, Critical Care & Anesthesia, UCL Great Ormond Street Institute of Child Health, London, UK

Development of therapeutic approaches for rare respiratory diseases is hampered by the lack of systems that allow medium-to-high-throughput screening of fully differentiated respiratory epithelium from affected patients. This is a particular problem for primary ciliary dyskinesia (PCD), a rare genetic disease caused by mutations in genes that adversely affect ciliary movement and consequently mucociliary transport. Primary cell culture of basal epithelial cells from nasal brush biopsies, followed by ciliated differentiation at air-liquid interface (ALI) has proven to be a useful tool in PCD diagnostics but the technique's broader utility, including in pre-clinical PCD research, has been restricted by the limited number of basal cells that it is possible to expand from such biopsies. Here, we describe an immunofluorescence screening method, enabled by extensive expansion of PCD patient basal cells and their culture into differentiated respiratory epithelium in miniaturised 96-well transwell format ALI cultures. Analyses of ciliary ultrastructure, beat pattern and beat frequency indicate that a range of different PCD defects can be retained in these cultures. As proof-of-principle, we performed a personalised investigation in a patient with a rare and severe form of PCD (reduced generation of motile cilia, RGMC), in this case caused by a homozygous nonsense mutation in the gene. The screening system allowed drugs that induce translational readthrough to be evaluated alone or in combination with nonsense-mediated decay inhibitors. Restoration of basal body formation in the patient's nasal epithelial cells was seen , suggesting a novel avenue for drug evaluation and development in PCD.
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http://dx.doi.org/10.1183/13993003.00455-2020DOI Listing
April 2021

Performance of Dutasteride-Nanostructured Lipid Carriers Coated with Lauric Acid-Chitosan Oligomer for Dermal Delivery.

Pharmaceutics 2020 Oct 20;12(10). Epub 2020 Oct 20.

Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, UK.

Dutasteride, licensed as an oral medicine for the treatment of benign prostatic hypoplasia, has been investigated as a treatment for androgenic alopecia. In this study, the potential for dustasteride to be delivered topically in order to reduce systemic exposure, irritation of the skin, and also cytotoxicity was explored. Chitosan oligomer (CSO) was successfully synthesised with lauric acid as a coating for a dutasteride-loaded nanostructured lipid carriers (DST-NLCs) system. DST-NLCs were prepared using a combination of melt-dispersion and ultrasonication. These negatively charged NLCs (-18.0 mV) had a mean particle size of ~184 nm, which was not significantly increased ( 0.05) when coated with lauric acid-chitosan oligomer (CSO-LA), whilst the surface charge changed to positive (+24.8 mV). The entrapment efficiency of DST-NLCs was 97%, and coated and uncoated preparations were physically stable for up to 180 days at 4-8 °C. The drug release was slower from DST-NLCs coated with CSO-LA than from uncoated NLCs, with no detectable drug permeation through full-thickness pig ear skin from either preparation. Considering the cytotoxicity, the IC values for the DST-NLCs, coated and uncoated with CSO-LA were greater than for dutasteride alone ( 0.05). DST-NLCs and empty NLCs coated with CSO-LA at 25 µM increased the cell proliferation compared to the control, and no skin irritation was observed when the DST-NLC formulations were tested using EpiDerm™. The cell and skin uptake studies of coated and uncoated NLCs incorporating the fluorescent marker Coumarin-6 showed the time-dependent uptake of Coumarin-6. Overall, the findings suggest that DST-NLCs coated with CSO-LA represent a promising formulation strategy for dutasteride delivery for the treatment of androgenic alopecia, with a reduced cytotoxicity compared to that of the drug alone and lower irritancy than an ethanolic solution of dutasteride.
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http://dx.doi.org/10.3390/pharmaceutics12100994DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7589135PMC
October 2020

Fluticasone Particles Bind to Motile Respiratory Cilia: A Mechanism for Enhanced Lung and Systemic Exposure?

J Aerosol Med Pulm Drug Deliv 2021 Jun 22;34(3):181-188. Epub 2020 Sep 22.

Respiratory, Critical Care, and Anesthesia, UCL Great Ormond Street Children's Hospital Institute of Child Health & NIHR GOSH BRC, London, United Kingdom.

Inhaled corticosteroids (ICSs) are the main prophylactic treatment for asthma and are used in other diseases, including chronic pulmonary obstructive disease, yet the interaction of ICS particles with the ciliated epithelium remains unclear. The aim of this study was to investigate the earliest interaction of aerosolized fluticasone propionate (FP) particles with human ciliated respiratory epithelium. A bespoke system was developed to allow aerosolized FP particles to be delivered to ciliated epithelial cultures by nebulization and from a pressurized metered-dose inhaler (pMDI) through a spacer with interactions observed in real time using high-speed video microscopy. Interaction with nonrespiratory cilia was investigated using steroids on brain ependymal ciliary cultures. The dissolution rate of steroid particles was determined. FP particles delivered by aerosol attached to the tips of rapidly beating cilia. Within 2 hours, 8.7% ± 1.8% (nebulization) and 12.1% ± 2.1% (pMDI through spacer) of ciliated cells had one or more particles attached to motile cilia. These levels decreased to 5.8% ± 1.6% ( = 0.59; nebulization) and 5.3% ± 2.2% ( = 0.14; pMDI through spacer) at 24 hours. Particle attachment did not affect ciliary beat frequency ( > 0.05) but significantly ( < 0.001) reduced ciliary beat amplitude. Steroid particles also attached to the tips of motile ependymal brain cilia and also reduced beat amplitude (24 hours: >2 particles bound  < 0.001). Dissolution of FP particles was slow with only 22.8% ± 1.3% of nebulized and 12.8% ± 0.5% of pMDI-delivered drug dissolving by 24 hours. FP particles adhere to the tips of rapidly moving cilia with significant numbers remaining bound at 24 hours, resisting the shear stress generated by ciliary beating. , this mechanism may predispose to high local drug concentrations and enhance respiratory and systemic corticosteroid exposure.
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http://dx.doi.org/10.1089/jamp.2020.1598DOI Listing
June 2021

N-Acetylcysteine Nanocarriers Protect against Oxidative Stress in a Cellular Model of Parkinson's Disease.

Antioxidants (Basel) 2020 Jul 9;9(7). Epub 2020 Jul 9.

School of Life Sciences, University of Westminster, 115 New Cavendish Street, London W1W 6UW, UK.

Oxidative stress is a key mediator in the development and progression of Parkinson's disease (PD). The antioxidant n-acetylcysteine (NAC) has generated interest as a disease-modifying therapy for PD but is limited due to poor bioavailability, a short half-life, and limited access to the brain. The aim of this study was to formulate and utilise mitochondria-targeted nanocarriers for delivery of NAC alone and in combination with the iron chelator deferoxamine (DFO), and assess their ability to protect against oxidative stress in a cellular rotenone PD model. Pluronic F68 (P68) and dequalinium (DQA) nanocarriers were prepared by a modified thin-film hydration method. An MTT assay assessed cell viability and iron status was measured using a ferrozine assay and ferritin immunoassay. For oxidative stress, a modified cellular antioxidant activity assay and the thiobarbituric acid-reactive substances assay and mitochondrial hydroxyl assay were utilised. Overall, this study demonstrates, for the first time, successful formulation of NAC and NAC + DFO into P68 + DQA nanocarriers for neuronal delivery. The results indicate that NAC and NAC + DFO nanocarriers have the potential characteristics to access the brain and that 1000 μM P68 + DQA NAC exhibited the strongest ability to protect against reduced cell viability ( = 0.0001), increased iron ( = 0.0033) and oxidative stress ( ≤ 0.0003). These NAC nanocarriers therefore demonstrate significant potential to be transitioned for further preclinical testing for PD.
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http://dx.doi.org/10.3390/antiox9070600DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7402157PMC
July 2020

Deferoxamine and Curcumin Loaded Nanocarriers Protect Against Rotenone-Induced Neurotoxicity.

J Parkinsons Dis 2020 ;10(1):99-111

School of Life Sciences, University of Westminster, London, UK.

Background: Reduced glutathione and excess free iron within dopaminergic, substantia nigra neurons in Parkinson's disease (PD) can drive accumulation of toxic hydroxyl radicals resulting in sustained oxidative stress and cellular damage. Factors such as brain penetrance and bioavailability have limited the advancement of potential antioxidant and iron chelator therapies for PD.

Objective: This study aimed to develop novel nanocarrier delivery systems for the antioxidant curcumin and/or iron chelator deferoxamine (DFO) to protect against rotenone-induced changes in cell viability and oxidative stress in SH-SY5Y cells.

Methods: Nanocarriers of curcumin and/or DFO were prepared using Pluronic F68 (P68) with or without dequilinium (DQA) by modified thin-film hydration. Cell viability was assessed using an MTT assay and oxidative stress was measured using thiobarbituric acid reactive substances and cellular antioxidant activity assays.

Results: All formulations demonstrated high encapsulation efficiency (65-96%) and nanocarrier size was <200 nm. 3-h pretreatment with P68 or P68+DQA nanocarriers containing various concentrations of curcumin and/or DFO significantly protected against rotenone-reduced cell viability. The addition of DFO to curcumin-loaded P68+DQA nanocarriers resulted in increased protection by at least 10%. All nanoformulations significantly protected against rotenone-induced lipid peroxidation (p < 0.0001). The addition of DQA, which targets mitochondria, resulted in up to 65% increase in cellular antioxidant activity. In nearly all preparations, the combination of 10 μM curcumin and 100 μM DFO had the most antioxidant activity.

Conclusion: This study demonstrates for the first time the formulation and delivery using P68 and P68+DQA curcumin and/or DFO nanocarriers to protect against oxidative stress induced by a rotenone PD model. This strategy to combine antioxidants with iron chelators may provide a novel approach to fully utilise their therapeutic benefit for PD.
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http://dx.doi.org/10.3233/JPD-191754DOI Listing
April 2021

Hydrophobically modified chitosan nanoliposomes for intestinal drug delivery.

Int J Nanomedicine 2018 27;13:5837-5848. Epub 2018 Sep 27.

Department of Pharmaceutics, University College London School of Pharmacy, London, UK,

Background: Encapsulation of hydrophilic drugs within liposomes can be challenging.

Methods: A novel chitosan derivative, O-palmitoyl chitosan (OPC) was synthesized from chitosan and palmitoyl chloride using methane-sulfonic acid as a solvent. The success of synthesis was confirmed by Fourier transform infra-red (FT-IR) spectroscopy and proton NMR spectroscopy (H-NMR). Liposomes encapsulating ferrous sulphate as a model hydrophilic drug for intestinal delivery were prepared with or without OPC inclusion (Lipo-Fe and OPC-Lipo-Fe).

Results: Entrapment of iron was significantly higher in OPC containing liposomes compared to controls. Quantitative iron absorption from the OPC liposomes was significantly higher (1.5-fold <0.05) than free ferrous sulphate controls. Qualitative uptake analysis by confocal imaging using coumarin-6 dye loaded liposomes also indicated higher cellular uptake and internalization of the OPC-containing liposomes.

Conclusion: These findings suggest that addition of OPC during liposome preparation creates robust vesicles that have improved mucoadhesive and absorption enhancing properties. The chitosan derivative OPC therefore provides a novel alternative for formulation of delivery vehicles targeting intestinal absorption.
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http://dx.doi.org/10.2147/IJN.S166901DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6166747PMC
November 2018

Topical Curcumin Nanocarriers are Neuroprotective in Eye Disease.

Sci Rep 2018 07 23;8(1):11066. Epub 2018 Jul 23.

UCL Institute of Ophthalmology, London, EC1V 9EL, United Kingdom.

Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5dione) is a polyphenol extracted from turmeric that has long been advocated for the treatment of a variety of conditions including neurodegenerative and inflammatory disorders. Despite this promise, the clinical use of curcumin has been limited by the poor solubility and low bioavailability of this molecule. In this article, we describe a novel nanocarrier formulation comprising Pluronic-F127 stabilised D-α-Tocopherol polyethene glycol 1000 succinate nanoparticles, which were used to successfully solubilize high concentrations (4.3 mg/mL) of curcumin. Characterisation with x-ray diffraction and in vitro release assays localise curcumin to the nanocarrier interior, with each particle measuring <20 nm diameter. Curcumin-loaded nanocarriers (CN) were found to significantly protect against cobalt chloride induced hypoxia and glutamate induced toxicity in vitro, with CN treatment significantly increasing R28 cell viability. Using established glaucoma-related in vivo models of ocular hypertension (OHT) and partial optic nerve transection (pONT), topical application of CN twice-daily for three weeks significantly reduced retinal ganglion cell loss compared to controls. Collectively, these results suggest that our novel topical CN formulation has potential as an effective neuroprotective therapy in glaucoma and other eye diseases with neuronal pathology.
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http://dx.doi.org/10.1038/s41598-018-29393-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6056418PMC
July 2018

Design and evaluation of the immunogenicity and efficacy of a biomimetic particulate formulation of viral antigens.

Sci Rep 2017 10 23;7(1):13743. Epub 2017 Oct 23.

Virology Department, Animal and Plant Health Agency, Woodham Lane, Addlestone, KT15 3NB, United Kingdom.

Subunit viral vaccines are typically not as efficient as live attenuated or inactivated vaccines at inducing protective immune responses. This paper describes an alternative 'biomimetic' technology; whereby viral antigens were formulated around a polymeric shell in a rationally arranged fashion with a surface glycoprotein coated on to the surface and non-structural antigen and adjuvant encapsulated. We evaluated this model using BVDV E2 and NS3 proteins formulated in poly-(D, L-lactic-co-glycolic acid) (PLGA) nanoparticles adjuvanted with polyinosinic:polycytidylic acid (poly(I:C) as an adjuvant (Vaccine-NP). This Vaccine-NP was compared to ovalbumin and poly(I:C) formulated in a similar manner (Control-NP) and a commercial adjuvanted inactivated BVDV vaccine (IAV), all inoculated subcutaneously and boosted prior to BVDV-1 challenge. Significant virus-neutralizing activity, and E2 and NS3 specific antibodies were observed in both Vaccine-NP and IAV groups following the booster immunisation. IFN-γ responses were observed in ex vivo PBMC stimulated with E2 and NS3 proteins in both vaccinated groups. We observed that the protection afforded by the particulate vaccine was comparable to the licenced IAV formulation. In conclusion, the biomimetic particulates showed a promising immunogenicity and efficacy profile that may be improved by virtue of being a customisable mode of delivery.
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http://dx.doi.org/10.1038/s41598-017-13915-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5653838PMC
October 2017

Preparation and characterization of dutasteride-loaded nanostructured lipid carriers coated with stearic acid-chitosan oligomer for topical delivery.

Eur J Pharm Biopharm 2017 Aug 12;117:372-384. Epub 2017 Apr 12.

Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address:

Dutasteride, used for treating benign prostate hyperplasia (BPH), promotes hair growth. To enhance delivery to the hair follicles and reduce systemic effects, in this study dutasteride has been formulated for topical application, in a nanostructured lipid carrier (NLC) coated with chitosan oligomer-stearic acid (CSO-SA). CSO-SA has been successfully synthesized, as confirmed using H NMR and FTIR. Formulation of dutasteride-loaded nanostructured lipid carriers (DST-NLCs) was optimized using a 2 full factorial design. This formulation was coated with different concentrations of stearic acid-chitosan solution. Coating DST-NLCs with 5% SA-CSO increased mean size from 187.6±7.0nm to 220.1±11.9nm, and modified surface charge, with zeta potentials being -18.3±0.9mV and +25.8±1.1mV for uncoated and coated DST-NLCs respectively. Transmission electron microscopy showed all formulations comprised approximately spherical particles. DST-NLCs, coated and uncoated with CSO-SA, exhibited particle size stability over 60days, when stored at 4-8°C. However, NLCs coated with CSO (without conjugation) showed aggregation when stored at 4-8°C after 30days. The measured particle size for all formulations stored at 25°C suggested aggregation, which was greatest for DST-NLCs coated with 10% CSO-SA and 5% CSO. All nanoparticle formulations exhibited rapid release in an in vitro release study, with uncoated NLCs exhibiting the fastest release rate. Using a Franz diffusion cell, no dutasteride permeated through pig ear skin after 48h, such that it was not detected in the receptor chamber for all samples. The amount of dutasteride in the skin was significantly different (p<0.05) for DST-NLCs (6.09±1.09μg/cm) without coating and those coated with 5% CSO-SA (2.82±0.40μg/cm), 10% CSO-SA (2.70±0.35μg/cm) and CSO (2.11±0.64μg/cm. There was a significant difference (p<0.05) in the cytotoxicity (IC) between dutasteride alone and in the nanoparticles. DST-NLCs coated and uncoated with CSO-SA increased the maximum non-toxic concentration by 20-fold compared to dutasteride alone. These studies indicate that a stearic acid-chitosan conjugate was successfully prepared, and modified the surface charge of DST-NLCs from negative to positive. These stable, less cytotoxic, positively-charged dutasteride-loaded nanostructured lipid carriers, with stearic acid-chitosan oligomer conjugate, are appropriate for topical delivery and have potential for promotion of hair growth.
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http://dx.doi.org/10.1016/j.ejpb.2017.04.012DOI Listing
August 2017

Study on the Pulmonary Delivery System of Apigenin-Loaded Albumin Nanocarriers with Antioxidant Activity.

J Aerosol Med Pulm Drug Deliv 2017 Aug 10;30(4):274-288. Epub 2017 Mar 10.

1 Department of Pharmaceutics, Semmelweis University , Budapest, Hungary .

Background: Respiratory diseases are mainly derived from acute and chronic inflammation of the alveoli and bronchi. The pathophysiological mechanisms of pulmonary inflammation mainly arise from oxidative damage that could ultimately lead to acute lung injury. Apigenin (Api) is a natural polyphenol with prominent antioxidant and anti-inflammatory properties in the lung. Inhalable formulations that consist of nanoparticles (NPs) have several advantages over other administration routes, and therefore, this study investigated the application of apigenin-loaded bovine serum albumin nanoparticles (BSA-Api-NPs) for pulmonary delivery.

Methods: Dry powder formulations of BSA-Api-NPs were prepared by spray drying and characterized by laser diffraction particle sizing, scanning electron microscopy, differential scanning calorimetry, and powder X-ray diffraction. The influence of dispersibility enhancers (lactose monohydrate and l-leucine) on the in vitro aerosol deposition using a next-generation impactor was investigated in comparison to excipient-free formulation. The dissolution of Api was determined in simulated lung fluid by using the Franz cell apparatus. The antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay.

Results: The encapsulation efficiency and the drug loading were measured to be 82.61% ± 4.56% and 7.51% ± 0.415%. The optimized spray drying conditions were suitable to produce particles with low residual moisture content. The spray-dried BSA-Api-NPs possessed good aerodynamic properties due to small and wrinkled particles with low mass median aerodynamic diameter, high emitted dose, and fine particle fraction. The aerodynamic properties were enhanced by leucine and decreased by lactose, however, the dissolution was reversely affected. The DPPH assay confirmed that the antioxidant activity of encapsulated Api was preserved.

Conclusion: This study provides evidence to support that albumin nanoparticles are suitable carriers of Api and the use of traditional or novel excipients should be taken into consideration. The developed BSA-Api-NPs are a novel delivery system against lung injury with potential antioxidant activity.
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http://dx.doi.org/10.1089/jamp.2016.1316DOI Listing
August 2017

Evaluation of hydrophobic chitosan-based particulate formulations of porcine reproductive and respiratory syndrome virus vaccine candidate T cell antigens.

Vet Microbiol 2017 Sep 3;209:66-74. Epub 2017 Feb 3.

Virology Department, Animal and Plant Health Agency, Addlestone, KT15 3NB, United Kingdom; Faculty of Health and Medical Sciences, University of Surrey, Guildford, GU2 7XH, United Kingdom. Electronic address:

PRRS control is hampered by the inadequacies of existing vaccines to combat the extreme diversity of circulating viruses. Since immune clearance of PRRSV infection may not be dependent on the development of neutralising antibodies and the identification of broadly-neutralising antibody epitopes have proven elusive, we hypothesised that conserved T cell antigens represent potential candidates for development of a novel PRRS vaccine. Previously we had identified the M and NSP5 proteins as well-conserved targets of polyfunctional CD8 and CD4 T cells. To assess their vaccine potential, peptides representing M and NSP5 were encapsulated in hydrophobically-modified chitosan particles adjuvanted by incorporation of a synthetic multi-TLR2/TLR7 agonist and coated with a model B cell PRRSV antigen. For comparison, empty particles and adjuvanted particles encapsulating inactivated PRRSV-1 were prepared. Vaccination with the particulate formulations induced antigen-specific antibody responses, which were most pronounced following booster immunisation. M and NSP5-specific CD4, but not CD8, T cell IFN-γ reactivity was measurable following the booster immunisation in a proportion of animals vaccinated with peptide-loaded particles. Upon challenge, CD4 and CD8 T cell reactivity was detected in all groups, with the greatest responses being detected in the peptide vaccinated group but with limited evidence of an enhanced control of viraemia. Analysis of the lungs during the resolution of infection showed significant M/NSP5 specific IFN-γ responses from CD8 rather than CD4 T cells. Vaccine primed CD8 T cell responses may therefore be required for protection and future work should focus on enhancing the cross-presentation of M/NSP5 to CD8 T cells.
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http://dx.doi.org/10.1016/j.vetmic.2017.01.037DOI Listing
September 2017

Novel biodegradable poly(gamma-glutamic acid)-amphotericin B complexes show promise as improved amphotericin B formulations.

Nanomedicine 2017 07 16;13(5):1773-1783. Epub 2017 Feb 16.

UCL School of Pharmacy, University College London, London, UK. Electronic address:

Commercially available amphotericin B (AmB) formulations are limited by cytotoxicities, lower efficacies, shelf-life related issues and high production costs. In this study, AmB complexes based on poly(gamma-glutamic acid) (PGGA) were prepared and evaluated for their efficacies against AmB-deoxycholate (Fungizone) and liposomal AmB (AmBisome). Physical characterizations showed that AmB/PGGA complexes are nanoscopic (20-40 nm) with a negative zeta potential (-45.5 to -51.0 mV), water-soluble, stable in solution (up to 4 weeks, at 4 °C and 25 °C), and have a high drug loading (up to 35% w/w). In vitro, AmB/PGGA complexes exhibited a more favorable cytotoxicity profile than Fungizone but comparable to AmBisome, with respect to the hemolytic activity and the modulation of pro-inflammatory cytokines (TNF-α and IL-1ß). In-vivo, AmB/PGGA complexes were significantly more efficacious than both Fungizone and AmBisome against experimental murine candidiasis. These results provide strong evidence that AmB/PGGA complexes display better efficacy and safety features than the currently approved AmB products.
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http://dx.doi.org/10.1016/j.nano.2017.02.003DOI Listing
July 2017

Mixed micelles of lipoic acid-chitosan-poly(ethylene glycol) and distearoylphosphatidylethanolamine-poly(ethylene glycol) for tumor delivery.

Eur J Pharm Sci 2017 Apr 3;101:228-242. Epub 2017 Feb 3.

UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address:

Many chemotherapeutics suffer from poor aqueous solubility and tissue selectivity. Distearoylphosphatidylethanolamine-poly(ethylene glycol) (DSPE-PEG) micelles are a promising formulation strategy for the delivery of hydrophobic anticancer drugs. However, storage and in vivo instability restrict their use. The aim of this study was to prepare mixed micelles, containing a novel polymer, lipoic acid-chitosan-poly(ethylene glycol) (LACPEG), and DSPE-PEG, to overcome these limitations and potentially increase cancer cell internalisation. Drug-loaded micelles were prepared with a model tyrosine kinase inhibitor and characterized for size, surface charge, stability, morphology, drug entrapment efficiency, cell viability (A549 and PC-9 cell lines), in vivo biodistribution, ex vivo tumor accumulation and cellular internalisation. Micelles of size 30-130nm with entrapment efficiencies of 46-81% were prepared. LACPEG/DSPE-PEG mixed micelles showed greater interaction with the drug (condensing to half their size following entrapment), greater stability, and a safer profile in vitro compared to DSPE-PEG micelles. LACPEG/DSPE-PEG and DSPE-PEG micelles had similar entrapment efficiencies and in vivo tumor accumulation levels, but LACPEG/DSPE-PEG micelles showed higher tumor cell internalisation. Collectively, these findings suggest that LACPEG/DSPE-PEG mixed micelles provide a promising platform for tumor delivery of hydrophobic drugs.
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http://dx.doi.org/10.1016/j.ejps.2017.02.001DOI Listing
April 2017

Design and development of dry powder sulfobutylether-β-cyclodextrin complex for pulmonary delivery of fisetin.

Eur J Pharm Biopharm 2017 Apr 1;113:1-10. Epub 2016 Dec 1.

Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom. Electronic address:

This study has investigated complexation of fisetin, a natural flavonoid, with three types of cyclodextrins to improve its solubility. Sulfobutylether-β-cyclodextrin (SBE-β-CD) showed the highest complexation efficiency while maintaining the in vitro antioxidant activity of fisetin. Addition of 20%v/v ethanol in water improved the amount of solubilized fisetin in the complex 5.9-fold compared to the system containing water alone. Spray drying of fisetin-SBE-β-CD complex solution in the presence of ethanol produced a dry powder with improved aerosolization properties when delivered from a dry powder inhaler, indicated by a 2-fold increase in the fine particle fraction (FPF) compared to the powder produced from the complex solution containing water alone. The pitted morphological surface of these particles suggested a more hollow internal structure, indicating a lighter and less dense powder. Incorporation of 20%w/w leucine improved the particle size distribution of the powder and further increased the FPF by 2.3-fold. This formulation also showed an EC value equivalent to fisetin alone in the A549 cell line. In conclusion, an inhalable dry powder containing fisetin-SBE-β-CD complex was successfully engineered with an improved aqueous solubility of fisetin. The dry powder may be useful to deliver high amounts of fisetin to the deep lung region for therapeutic purposes.
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http://dx.doi.org/10.1016/j.ejpb.2016.11.036DOI Listing
April 2017

Preparation of theophylline inhalable microcomposite particles by wet milling and spray drying: The influence of mannitol as a co-milling agent.

Int J Pharm 2016 Nov;514(1):200-211

UCL School of Pharmacy, 29-39 Brunswick Square, London, WC1N 1AX, UK. Electronic address:

Inhalable theophylline particles with various amounts of mannitol were prepared by combining wet milling in isopropanol followed by spray drying. The effect of mannitol as a co-milling agent on the micromeritic properties, solid state and aerosol performance of the engineered particles was investigated. Crystal morphology modelling and geometric lattice matching calculations were employed to gain insight into the intermolecular interactions that may influence the mechanical properties of theophylline and mannitol. The addition of mannitol facilitated the size reduction of the needle-like crystals of theophylline and also their assembly in microcomposites by forming a porous structure of mannitol nanocrystals wherein theophylline particles are embedded. The microcomposites were found to be in the same crystalline state as the starting material(s) ensuring their long-term physical stability upon storage. Incorporation of mannitol resulted in microcomposite particles with smaller size, more spherical shape and increased porosity. The aerosol performance of the microcomposites was markedly enhanced compared to the spray-dried suspension of theophylline wet milled without mannitol. Overall, wet co-milling with mannitol in an organic solvent followed by spray drying may be used as a formulation approach for producing respirable particles of water-soluble drugs or drugs that are prone to crystal transformation in an aqueous environment (i.e. formation of hydrates).
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http://dx.doi.org/10.1016/j.ijpharm.2016.06.032DOI Listing
November 2016

The retina as an early biomarker of neurodegeneration in a rotenone-induced model of Parkinson's disease: evidence for a neuroprotective effect of rosiglitazone in the eye and brain.

Acta Neuropathol Commun 2016 08 18;4(1):86. Epub 2016 Aug 18.

Imperial College Ophthalmology Research Group (ICORG), Department of Surgery and Cancer, Faculty of Medicine, Imperial College London, London, UK.

Parkinson's Disease (PD) is the second most common neurodegenerative disease worldwide, affecting 1 % of the population over 65 years of age. Dopaminergic cell death in the substantia nigra and accumulation of Lewy bodies are the defining neuropathological hallmarks of the disease. Neuronal death and dysfunction have been reported in other central nervous system regions, including the retina. Symptoms of PD typically manifest only when more than 70 % of dopaminergic cells are lost, and the definitive diagnosis of PD can only be made histologically at post-mortem, with few biomarkers available.In this study, a rotenone-induced rodent model of PD was employed to investigate retinal manifestations in PD and their usefulness in assessing the efficacy of a novel therapeutic intervention with a liposomal formulation of the PPAR-γ (Peroxisome proliferator-activated receptor gamma) agonist rosiglitazone.Retinal assessment was performed using longitudinal in vivo imaging with DARC (detection of apoptosing retinal cells) and OCT (optical coherence tomography) technologies and revealed increased RGCs (Retinal Ganglion Cells) apoptosis and a transient swelling of the retinal layers at day 20 of the rotenone insult. Follow-up of this model demonstrated characteristic histological neurodegenerative changes in the substantia nigra and striatum by day 60, suggesting that retinal changes precede the "traditional" pathological manifestations of PD. The therapeutic effect of systemic administration of different formulations of rosiglitazone was then evaluated, both in the retina and the brain. Of all treatment regimen tested, sustained release administration of liposome-encapsulated rosiglitazone proved to be the most potent therapeutic strategy, as evidenced by its significant neuroprotective effect on retinal neurons at day 20, and on nigrostriatal neurons at day 60, provided convincing evidence for its potential as a treatment for PD.Our results demonstrate significant retinal changes occurring in this model of PD. We show that rosiglitazone can efficiently protect retinal neurons from the rotenone insult, and that systemic administration of liposome-encapsulated rosiglitazone has an enhanced neuroprotective effect on the retina and CNS (Central Nervous System). To our knowledge, this is the first in vivo evidence of RGCs loss and early retinal thickness alterations in a PD model. Together, these findings suggest that retinal changes may be a good surrogate biomarker for PD, which may be used to assess new treatments both experimentally and clinically.
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http://dx.doi.org/10.1186/s40478-016-0346-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4989531PMC
August 2016

Advanced nanostructured medical device combining mesenchymal cells and VEGF nanoparticles for enhanced engineered tissue vascularization.

Nanomedicine (Lond) 2016 Sep 16;11(18):2419-30. Epub 2016 Aug 16.

INSERM (French National Institute of Health & Medical Research), "Osteoarticular & Dental Regenerative Nanomedicine" Laboratory, UMR 1109, Faculté de Médecine, F-67085 Strasbourg Cedex. FMTS, France.

Aim: Success of functional vascularized tissue repair depends on vascular support system supply and still remains challenging. Our objective was to develop a nanoactive implant enhancing endothelial cell activity, particularly for bone tissue engineering in the regenerative medicine field.

Materials & Methods: We developed a new strategy of tridimensional implant based on cell-dependent sustained release of VEGF nanoparticles. These nanoparticles were homogeneously distributed within nanoreservoirs onto the porous scaffold, with quicker reorganization of endothelial cells. Moreover, the activity of this active smart implant on cells was also modulated by addition of osteoblastic cells.

Results & Conclusion: This sophisticated active strategy should potentiate efficiency of current therapeutic implants for bone repair, avoiding the need for bone substitutes.
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http://dx.doi.org/10.2217/nnm-2016-0189DOI Listing
September 2016

PLGA Microparticles Entrapping Chitosan-Based Nanoparticles for the Ocular Delivery of Ranibizumab.

Mol Pharm 2016 09 22;13(9):2923-40. Epub 2016 Jun 22.

University College London School of Pharmacy , London, United Kingdom.

Age-related macular degeneration (AMD) is the leading cause of certified vision loss worldwide. The standard treatment for neovascular AMD involves repeated intravitreal injections of therapeutic proteins directed against vascular endothelial growth factor, such as ranibizumab. Biodegradable polymers, such as poly(lactic-co-glycolic acid) (PLGA), form delivery vehicles which can be used to treat posterior segment eye diseases, but suffer from poor protein loading and release. This work describes a "system-within-system", PLGA microparticles incorporating chitosan-based nanoparticles, for improved loading and sustained intravitreal delivery of ranibizumab. Chitosan-N-acetyl-l-cysteine (CNAC) was synthesized and its synthesis confirmed using FT-IR and (1)H NMR. Chitosan-based nanoparticles composed of CNAC, CNAC/tripolyphosphate (CNAC/TPP), chitosan, chitosan/TPP (chit/TPP), or chit/TPP-hyaluronic acid (chit/TPP-HA) were incorporated in PLGA microparticles using a modified w/o/w double emulsion method. Nanoparticles and final nanoparticles-within-microparticles were characterized for their protein-nanoparticle interaction, size, zeta potential, morphology, protein loading, stability, in vitro release, in vivo antiangiogenic activity, and effects on cell viability. The prepared nanoparticles were 17-350 nm in size and had zeta potentials of -1.4 to +12 mV. Microscopic imaging revealed spherical nanoparticles on the surface of PLGA microparticles for preparations containing chit/TPP, CNAC, and CNAC/TPP. Ranibizumab entrapment efficiency in the preparations varied between 13 and 69% and was highest for the PLGA microparticles containing CNAC nanoparticles. This preparation also showed the slowest release with no initial burst release compared to all other preparations. Incorporation of TPP to this formulation increased the rate of protein release and reduced entrapment efficiency. PLGA microparticles containing chit/TPP-HA showed the fastest and near-complete release of ranibizumab. All of the prepared empty particles showed no effect on cell viability up to a concentration of 12.5 mg/mL. Ranibizumab released from all preparations maintained its structural integrity and in vitro activity. The chit/TPP-HA preparation enhanced antiangiogenic activity and may provide a potential biocompatible platform for enhanced antiangiogenic activity in combination with ranibizumab. In conclusion, the PLGA microparticles containing CNAC nanoparticles showed significantly improved ranibizumab loading and release profile. This novel drug delivery system may have potential for improved intravitreal delivery of therapeutic proteins, thereby reducing the frequency, risk, and cost of burdensome intravitreal injections.
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http://dx.doi.org/10.1021/acs.molpharmaceut.6b00335DOI Listing
September 2016

A New Era of Pulmonary Delivery of Nano-antimicrobial Therapeutics to Treat Chronic Pulmonary Infections.

Curr Pharm Des 2016 ;22(17):2577-98

Department of Pharmaceutics, School of Pharmacy, University College London, 29-39 Brunswick Square, London WC1N 1AX; United Kingdom.

Pulmonary infections may be fatal especially in immunocompromised patients and patients with underlying pulmonary dysfunction, such as those with cystic fibrosis, chronic obstructive pulmonary disorder, etc. According to the WHO, lower respiratory tract infections ranked first amongst the leading causes of death in 2012, and tuberculosis was included in the top 10 causes of death in low income countries, placing a considerable strain on their economies and healthcare systems. Eradication of lower respiratory infections is arduous, leading to high healthcare costs and requiring higher doses of antibiotics to reach optimal concentrations at the site of pulmonary infection for protracted periods. Hence direct inhalation to the respiratory epithelium has been investigated extensively in the past decade, and seems to be an attractive approach to eradicate and hence overcome this widespread problem. Moreover, engineering inhalation formulations wherein the antibiotics are encapsulated within nanoscale carriers could serve to overcome many of the limitations faced by conventional antibiotics, like difficulty in treating intracellular pathogens such as mycobacteria spp. and salmonella spp., biofilmassociated pathogens like Pseudomonas aeruginosa and Staphylococcus aureus, passage through the sputum associated with disorders like cystic fibrosis and chronic obstructive pulmonary disorder, systemic side effects following oral/parenteral delivery and inadequate concentrations of antibiotic at the site of infection leading to resistance. Encapsulation of antibiotics in nanocarriers may help in providing a protective environment to combat antibiotic degradation, confer controlled-release properties, hence reducing dosing frequency, and may increase uptake via specific and non-specific targeting modalities. Hence nanotechnology combined with direct administration to the airways using commercially available delivery devices, is a highly attractive formulation strategy to eradicate microorganisms from the lower respiratory tract, which might otherwise present opportunities for multi-drug resistance.
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http://dx.doi.org/10.2174/1381612822666160317142139DOI Listing
November 2017

The Non-structural Protein 5 and Matrix Protein Are Antigenic Targets of T Cell Immunity to Genotype 1 Porcine Reproductive and Respiratory Syndrome Viruses.

Front Immunol 2016 16;7:40. Epub 2016 Feb 16.

Virology Department, Animal and Plant Health Agency , Addlestone , UK.

The porcine reproductive and respiratory syndrome virus (PRRSV) is the cause of one of the most economically important diseases affecting swine worldwide. Efforts to develop a next-generation vaccine have largely focused on envelope glycoproteins to target virus-neutralizing antibody responses. However, these approaches have failed to demonstrate the necessary efficacy to progress toward market. T cells are crucial to the control of many viruses through cytolysis and cytokine secretion. Since control of PRRSV infection is not dependent on the development of neutralizing antibodies, it has been proposed that T cell-mediated immunity plays a key role. Therefore, we hypothesized that conserved T cell antigens represent prime candidates for the development a novel PRRS vaccine. Antigens were identified by screening a proteome-wide synthetic peptide library with T cells from cohorts of pigs rendered immune by experimental infections with a closely related (subtype 1) or divergent (subtype 3) PRRSV-1 strain. Dominant T cell IFN-γ responses were directed against the non-structural protein 5 (NSP5), and to a lesser extent, the matrix (M) protein. The majority of NSP5-specific CD8 T cells and M-specific CD4 T cells expressed a putative effector memory phenotype and were polyfunctional as assessed by coexpression of TNF-α and mobilization of the cytotoxic degranulation marker CD107a. Both antigens were generally well conserved among strains of both PRRSV genotypes. Thus, M and NSP5 represent attractive vaccine candidate T cell antigens, which should be evaluated further in the context of PRRSV vaccine development.
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http://dx.doi.org/10.3389/fimmu.2016.00040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4755262PMC
February 2016

Solidification of nanosuspensions for the production of solid oral dosage forms and inhalable dry powders.

Expert Opin Drug Deliv 2016 3;13(3):435-50. Epub 2016 Feb 3.

a Department of Pharmaceutics , UCL School of Pharmacy , London , UK.

Introduction: Nanosuspensions combine the advantages of nanotherapeutics (e.g. increased dissolution rate and saturation solubility) with ease of commercialisation. Transformation of nanosuspensions to solid oral and inhalable dosage forms minimises the physical instability associated with their liquid state, enhances patient compliance and enables targeted oral and pulmonary drug delivery.

Areas Covered: This review outlines solidification methods for nanosuspensions. It includes spray and freeze drying as the most widely used techniques. Fluidised-bed coating, granulation and pelletisation are also discussed as they yield nanocrystalline formulations with more straightforward downstream processing to tablets or capsules. Spray-freeze drying, aerosol flow reactor and printing of nanosuspensions are also presented as promising alternative solidification techniques. Results regarding the solid state, in vitro dissolution and/or aerosolisation efficiency of the nanocrystalline formulations are given and combined with available in vivo data. Focus is placed on the redispersibility of the solid nanocrystalline formulations, which is a prerequisite for their clinical application.

Expert Opinion: A few solidified nanocrystalline products are already on the market and many more are in development. Oral and inhalable nanoparticle formulations are expected to have great potential especially in the areas of personalised medicine and delivery of high drug doses (e.g. antibiotics) to the lungs, respectively.
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http://dx.doi.org/10.1517/17425247.2016.1142524DOI Listing
July 2016

Assessment of the enhancement of PLGA nanoparticle uptake by dendritic cells through the addition of natural receptor ligands and monoclonal antibody.

Vaccine 2015 Nov 1;33(48):6588-95. Epub 2015 Nov 1.

Virology Department, Animal and Plant Health Agency, Woodham Lane, Addlestone KT15 3NB, United Kingdom. Electronic address:

Targeting of specific receptors on antigen-presenting cells is an appealing prospect in the production of novel nanoparticulate vaccines. In particular, the targeting of vaccines to dendritic cell (DC) subsets has been shown in models to significantly improve the induction of immune responses. This paper describes the evaluation of natural ligands, mannan and chitosan, and monoclonal antibodies as targeting motifs to enhance uptake of PLGA nanoparticle carriers by bovine DCs. To assess enhancement of uptake after the addition of natural ligands a bovine monocyte derived DC (MoDC) model was used. For the assessment of monoclonal antibody targeting, the model was expanded to include afferent lymph DCs (ALDCs) in a competitive uptake assay. Mannan, proved unsuccessful at enhancing uptake or targeting by MoDCs. Chitosan coated particle uptake could be impeded by the addition of mannan suggesting uptake may be mediated through sugar receptors. Inclusion of monoclonal antibodies specific for the DEC-205 (CD205) receptor increased the number of receptor expressing DCs associated with particles as well as the number of particles taken up by individual cells. These results support the further evaluation of active targeting of nanovaccines to DCs to enhance their immunogenicity in cattle and other large mammalian species including humans.
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http://dx.doi.org/10.1016/j.vaccine.2015.10.093DOI Listing
November 2015

Pulmonary Delivery of Proteins Using Nanocomposite Microcarriers.

J Pharm Sci 2015 Dec 27;104(12):4386-4398. Epub 2015 Oct 27.

School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK. Electronic address:

In this study, Taguchi design was used to determine optimal parameters for the preparation of bovine serum albumin (BSA)-loaded nanoparticles (NPs) using a biodegradable polymer poly(glycerol adipate-co-ω-pentadecalactone) (PGA-co-PDL). NPs were prepared, using BSA as a model protein, by the double emulsion evaporation process followed by spray-drying from leucine to form nanocomposite microparticles (NCMPs). The effect of various parameters on NP size and BSA loading were investigated and dendritic cell (DC) uptake and toxicity. NCMPs were examined for their morphology, yield, aerosolisation, in vitro release behaviour and BSA structure. NP size was mainly affected by the polymer mass used and a small particle size ≤500 nm was achieved. High BSA (43.67 ± 2.3 μg/mg) loading was influenced by BSA concentration. The spray-drying process produced NCMPs (50% yield) with a porous corrugated surface, aerodynamic diameter 1.46 ± 141 μm, fine particle dose 45.0 ± 4.7 μg and fine particle fraction 78.57 ± 0.1%, and a cumulative BSA release of 38.77 ± 3.0% after 48 h. The primary and secondary structures were maintained as shown by sodium dodecyl sulphate poly (acrylamide) gel electrophoresis and circular dichroism. Effective uptake of NPs was seen in DCs with >85% cell viability at 5 mg/mL concentration after 4 h. These results indicate the optimal process parameters for the preparation of protein-loaded PGA-co-PDL NCMPs suitable for inhalation.
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http://dx.doi.org/10.1002/jps.24681DOI Listing
December 2015

Development of chitosan-pullulan composite nanoparticles for nasal delivery of vaccines: in vivo studies.

J Microencapsul 2015 31;32(8):769-83. Epub 2015 Aug 31.

b Department of Pharmaceutics , The UCL School of Pharmacy, University of London , London , United Kingdom .

Here, we aimed at developing chitosan/pullulan composite nanoparticles and testing their potential as novel systems for the nasal delivery of diphtheria toxoid (DT). All the chitosan derivatives [N-trimethyl (TMC), chloride and glutamate] and carboxymethyl pullulan (CMP) were synthesised and antigen-loaded composites were prepared by polyion complexation of chitosan and pullulan derivatives (particle size: 239-405 nm; surface charge: +18 and +27 mV). Their immunological effects after intranasal administration to mice were compared to intramuscular route. Composite nanoparticles induced higher levels of IgG responses than particles formed with chitosan derivative and antigen. Nasally administered TMC-pullulan composites showed higher DT serum IgG titre when compared with the other composites. Co-encapsulation of CpG ODN within TMC-CMP-DT nanoparticles resulted in a balanced Th1/Th2 response. TMC/pullulan composite nanoparticles also induced highest cytokine levels compared to those of chitosan salts. These findings demonstrated that TMC-CMP-DT composite nanoparticles are promising delivery system for nasal vaccination.
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http://dx.doi.org/10.3109/02652048.2015.1073393DOI Listing
August 2016

Pulmonary dry powder vaccine of pneumococcal antigen loaded nanoparticles.

Int J Pharm 2015 Nov 18;495(2):903-12. Epub 2015 Sep 18.

Formulation and Drug Delivery Research, School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, UK. Electronic address:

Pneumonia, caused by Streptococcus pneumoniae, mainly affects the immunocompromised, the very young and the old, and remains one of the leading causes of death. A steady rise in disease numbers from non-vaccine serotypes necessitates a new vaccine formulation that ideally has better antigen stability and integrity, does not require cold-chain and can be delivered non-invasively. In this study, a dry powder vaccine containing an important antigen of S. pneumoniae, pneumococcal surface protein A (PspA) that has shown cross-reactivity amongst serotypes to be delivered via the pulmonary route has been formulated. The formulation contains the antigen PspA adsorbed onto the surface of polymeric nanoparticles encapsulated in L-leucine microparticles that can be loaded into capsules and delivered via an inhaler. We have successfully synthesized particles of ∼150 nm and achieved ∼20 μg of PspA adsorption per mg of NPs. In addition, the spray-dried powders displayed a FPF of 74.31±1.32% and MMAD of 1.70±0.03 μm suggesting a broncho-alveolar lung deposition facilitating the uptake of the nanoparticles by dendritic cells. Also, the PspA released from the dry powders maintained antigen stability (SDS-PAGE), integrity (Circular dichroism) and activity (lactoferrin binding assay). Moreover, the released antigen also maintained its antigenicity as determined by ELISA.
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http://dx.doi.org/10.1016/j.ijpharm.2015.09.034DOI Listing
November 2015

Nanoparticle agglomerates of indomethacin: The role of poloxamers and matrix former on their dissolution and aerosolisation efficiency.

Int J Pharm 2015 Nov 10;495(1):516-526. Epub 2015 Sep 10.

UCL School of Pharmacy, 29-39 Brunswick Square, London, WC1N 1AX, UK. Electronic address:

Nanoparticles (NPs) were prepared and assembled to microsized agglomerates with and without matrix formers (mannitol and L-leucine) by coupling wet milling and spray drying to harmonise the advantages of NPs with handling and aerodynamics of microparticles without induction of amorphisation. Indomethacin was selected as poorly water-soluble drug and poloxamers with different ratios of hydrophilic to hydrophobic domains were evaluated as stabilisers comparatively to D-α-Tocopherol polyethylene-glycol succinate (TPGS). Particle size of nanosuspensions and morphology, size, crystal form, drug loading, redispersibility, in vitro dissolution, and in vitro aerosolisation of NP-agglomerates were determined. Molecular weight of stabilisers affected the rate but not the limit of NP size reduction and the length of hydrophilic segment in poloxamers was found important for the nanosuspension stabilisation. SEM revealed the structure of agglomerates consisting of nanocrystal assemblies. XRPD with DSC proved that NP agglomerates retained their crystallinity. NP-agglomerates exhibited enhanced dissolution compared to physical mixtures of drug and stabilisers while incorporation of matrix formers enabled redispersibility upon hydration and further increased the drug dissolution. Also, matrix formers resulted in significantly improved aerosolisation with higher fine particle fractions (49-62%) and smaller mass median aerodynamic diameters (<3.5 μm), compared to cases without matrix formers (34-43% and <4.5 μm).
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http://dx.doi.org/10.1016/j.ijpharm.2015.09.013DOI Listing
November 2015

Comparative evaluation of the effect of cyclodextrins and pH on aqueous solubility of apigenin.

J Pharm Biomed Anal 2016 Jan 20;117:210-6. Epub 2015 Aug 20.

Department of Pharmaceutics, Semmelweis University, Hőgyes E. Street 7-9, H-1092 Budapest, Hungary. Electronic address:

The aqueous solubility of a flavonoid, apigenin, was studied in the presence of first generation cyclodextrins (α-CyD, β-CyD, γ-CyD), ionic and nonionic synthetic derivatives of β-CyD, namely SBE-β-CyD, HP-β-CyD and RM-β-CyD at various physiological pH. The order of solubility enhancement was as follows: RM-β-CyD>SBE-β-CyD>γ-CyD>HP-β-CyD>β-CyD>α-CyD. The phase solubility diagrams of HP-β-CyD and SBE-β-CyD indicated Higuchi AL subtype behavior, suggesting 1:1 stoichiometry of the complex. In contrast, AP subtype, so higher order complex formation can be assumed in the case of RM-β-CyD and γ-CyD. The formation of inclusion complexes has been confirmed by absorption and fluorescence spectroscopic measurements. Increased antioxidant activity was observed due to the inclusion complexes. These results prove that synthetic derivatives of β-CyD will be potentially useful excipients in the development of drug delivery systems for healthcare products containing flavonoids.
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http://dx.doi.org/10.1016/j.jpba.2015.08.019DOI Listing
January 2016

Dry powder pulmonary delivery of cationic PGA-co-PDL nanoparticles with surface adsorbed model protein.

Int J Pharm 2015 Aug 10;492(1-2):213-22. Epub 2015 Jul 10.

Formulation and Drug Delivery Research, School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Liverpool, United Kingdom. Electronic address:

Pulmonary delivery of macromolecules has been the focus of attention as an alternate route of delivery with benefits such as; large surface area, thin alveolar epithelium, rapid absorption and extensive vasculature. In this study, a model protein, bovine serum albumin (BSA) was adsorbed onto cationic PGA-co-PDL polymeric nanoparticles (NPs) prepared by a single emulsion solvent evaporation method using a cationic surfactant didodecyldimethylammonium bromide (DMAB) at 2% w/w (particle size: 128.64±06.01 nm and zeta-potential: +42.32±02.70 mV). The optimum cationic NPs were then surface adsorbed with BSA, NP:BSA (100:4) ratio yielded 10.01±1.19 μg of BSA per mg of NPs. The BSA adsorbed NPs (5 mg/ml) were then spray-dried in an aqueous suspension of L-leucine (7.5 mg/ml, corresponding to a ratio of 1:1.5/NP:L-leu) using a Büchi-290 mini-spray dryer to produce nanocomposite microparticles (NCMPs) containing cationic NPs. The aerosol properties showed a fine particle fraction (FPF, dae<4.46 μm) of 70.67±4.07% and mass median aerodynamic diameter (MMAD) of 2.80±0.21 μm suggesting a deposition in the respiratory bronchiolar region of the lungs.The cell viability was 75.76±03.55% (A549 cell line) at 156.25 μg/ml concentration after 24 h exposure. SDS-PAGE and circular dichroism (CD) confirmed that the primary and secondary structure of the released BSA was maintained. Moreover, the released BSA showed 78.76±1.54% relative esterolytic activity compared to standard BSA.
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http://dx.doi.org/10.1016/j.ijpharm.2015.07.015DOI Listing
August 2015

Engineering hydrophobically modified chitosan for enhancing the dispersion of respirable microparticles of levofloxacin.

Eur J Pharm Biopharm 2014 Nov 8;88(3):816-29. Epub 2014 Oct 8.

University College London School of Pharmacy, London, United Kingdom. Electronic address:

The potential of amphiphilic chitosan formed by grafting octanoyl chains on the chitosan backbone for pulmonary delivery of levofloxacin has been studied. The success of polymer synthesis was confirmed using FT-IR and NMR, whilst antimicrobial activity was assessed against Pseudomonas aeruginosa. Highly dispersible dry powders for delivery as aerosols were prepared with different amounts of chitosan and octanoyl chitosan to study the effect of hydrophobic modification and varying concentration of polymer on aerosolization of drug. Powders were prepared by spray-drying from an aqueous solution containing levofloxacin and chitosan/amphiphilic octanoyl chitosan. l-leucine was also used to assess its effect on aerosolization. Following spray-drying, the resultant powders were characterized using scanning electron microscopy, laser diffraction, dynamic light scattering, HPLC, differential scanning calorimetry, thermogravimetric analysis and X-ray powder diffraction. The in vitro aerosolization profile was determined using a Next Generation Impactor, whilst in vitro antimicrobial assessment was performed using MIC assay. Microparticles of chitosan have the property of mucoadhesion leading to potential increased residence time in the pulmonary mucus, making it important to test the toxicity of these formulations. In-vitro cytotoxicity evaluation using MTT assay was performed on A549 cell line to determine the toxicity of formulations and hence feasibility of use. The MTT assay confirmed that the polymers and the formulations were non-cytotoxic. Hydrophobically modifying chitosan showed significantly lower MIC (4-fold) than the commercial chitosan against P. aeruginosa. The powders generated were of suitable aerodynamic size for inhalation having a mass median aerodynamic diameter less than 4.5μm for formulations containing octanoyl chitosan. These highly dispersible powders have minimal moisture adsorption and hence an emitted dose of more than 90% and a fine particle fraction (FPF) of 52%. Powders with non-modified chitosan showed lower dispersibility, with an emitted dose of 72% and FPF of 20%, as a result of high moisture adsorption onto the chitosan matrix leading to cohesiveness and subsequently decreased dispersibility.
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http://dx.doi.org/10.1016/j.ejpb.2014.09.005DOI Listing
November 2014
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