Publications by authors named "Mohamed A Shaker"

15 Publications

  • Page 1 of 1

Enhancement of atorvastatin oral bioavailability via encapsulation in polymeric nanoparticles.

Int J Pharm 2021 Jan 24;592:120077. Epub 2020 Nov 24.

Department of Pharmaceutics, Faculty of Pharmacy, King Khalid University, Abha, Saudi Arabia.

Despite the fact that atrovastatin (At) is being one of the bestselling statins used to prevent complicated cardiovascular diseases, its low oral bioavailability decreases its clinical relevance. Herein, incorporation of At into ethylcellulose nanoparticles (At-NPs) was executed to test if it would enhance its oral bioavailability. The emulsification-evaporation method was used to prepare the At-NPs. The prepared nanoparticles were characterized by measuring the particle size, zeta potential as well as using FTIR, DSC, and XRD examination. The entrapment efficiency, drug content, and the in vitro release behavior of At-NPs were also examined. The in vivo oral bioavailability of the selected At-NPs formula was tested after being given orally to New Zealand rabbits. The nanoparticles obtained had a high drug content and a distinct spherical shape but with varying sizes. No physical or chemical interactions were detected between At and the nanoparticles as confirmed by FTIR, DSC, and XRD. The in vitro release study of At from the prepared At-NPs has shown nanoparticles size-dependent release behavior. The in vivo oral absorption testing confirmed the bioavailability of the prepared At-NPs to be as follows: (C = 940 ng/ml and AUC = 8759 ng.h/ml) > Lipitor® (C = 635 ng/ml and AUC = 4367 ng.h/ml) > At (C = 515 ng/ml and AUC = 2517 ng.h/ml). These results revealed that the oral formula of At-NPs increases the bioavailability of At 3.87 times. This makes ethylcellulose nanoparticles an esteemed candidate nano-vehicle for At, increasing its bioavailability and thus improving its clinical relevance.
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http://dx.doi.org/10.1016/j.ijpharm.2020.120077DOI Listing
January 2021

Generation of Combinatorial Lentiviral Vectors Expressing Multiple Anti-Hepatitis C Virus shRNAs and Their Validation on a Novel HCV Replicon Double Reporter Cell Line.

Viruses 2020 09 18;12(9). Epub 2020 Sep 18.

Department of Molecular Medicine, University of Padua, 35121 Padua, Italy.

Despite the introduction of directly acting antivirals (DAAs), for the treatment of hepatitis C virus (HCV) infection, their cost, patient compliance, and viral resistance are still important issues to be considered. Here, we describe the generation of a novel JFH1-based HCV subgenomic replicon double reporter cell line suitable for testing different antiviral drugs and therapeutic interventions. This cells line allowed a rapid and accurate quantification of cell growth/viability and HCV RNA replication, thus discriminating specific from unspecific antiviral effects caused by DAAs or cytotoxic compounds, respectively. By correlating cell number and virus replication, we could confirm the inhibitory effect on the latter of cell over confluency and characterize an array of lentiviral vectors expressing single, double, or triple cassettes containing different combinations of short hairpin (sh)RNAs, targeting both highly conserved viral genome sequences and cellular factors crucial for HCV replication. While all vectors were effective in reducing HCV replication, the ones targeting viral sequences displayed a stronger antiviral effect, without significant cytopathic effects. Such combinatorial platforms as well as the developed double reporter cell line might find application both in setting-up anti-HCV gene therapy approaches and in studies aimed at further dissecting the viral biology/pathogenesis of infection.
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http://dx.doi.org/10.3390/v12091044DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551853PMC
September 2020

Improved solubility, dissolution, and oral bioavailability for atorvastatin-Pluronic® solid dispersions.

Int J Pharm 2020 Jan 28;574:118891. Epub 2019 Nov 28.

Department of Pharmaceutics, Faculty of Pharmacy, King Khalid University, Abha, Saudi Arabia.

Despite the status of atorvastatin (AT) as one of the top selling statins for prophylaxis against primary and secondary cardiovascular diseases, its limited oral absorption limits its full therapeutic benefits. Herein, formulations of AT with amphiphilic carriers (Pluronic F127® and Pluronic F68®) were developed in the form of hard capsules to improve in vitro solubility and dissolution, as well as in vivo oral bioavailability. Prepared formulas were characterized by assessing solubility improvements in the carrier solution and examining the FTIR, DSC, and X-RPD profiles for each formula. The dissolution rate and absorption were also examined after oral administration to New Zealand rabbits. The solubility of AT was improved by the incorporation of either Pluronic F127® or Pluronic F68®. No chemical changes or interactions were detected using X-RPD, DSC, and FTIR characterization. Dissolution profiles revealed an increase in the rate and maximum amount of dissolved AT and showed that up to 93% of the AT content was dissolved within 30 min. In vivo absorption of the tested formula (C = 1146 ng/ml and AUC0-12 to 9,993.4 ng.h/ml) was greater than Lipitor® (C = 642.3 ng/ml and AUC0-12 = 4427.4 ng.h/ml) and AT (C = 517.6 ng/ml and AUC0- 12 = 2,473.7 ng.h/ml). In conclusion, the formulation of AT with Pluronics® profoundly augments the dissolution behavior and absorption of AT and may serve as a useful approach for improving AT therapeutic and clinical efficacy.
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http://dx.doi.org/10.1016/j.ijpharm.2019.118891DOI Listing
January 2020

Recent expansions of novel strategies towards the drug targeting into the brain.

Int J Nanomedicine 2019 30;14:5895-5909. Epub 2019 Jul 30.

Pharmaceutics Department, Faculty of Pharmacy, Helwan University, Cairo, Egypt.

The treatment of central nervous system (CNS) disorders always remains a challenge for the researchers. The presence of various physiological barriers, primarily the blood-brain barrier (BBB) limits the accessibility of the brain and hinders the efficacy of various drug therapies. Hence, drug targeting to the brain, particularly to the diseased cells by circumventing the physiological barriers is essential to develop a promising therapy for the treatment of brain disorders. Presently, the investigations emphasize the role of different nanocarrier systems or surface modified target specific novel carrier system to improve the efficiency and reduce the side effects of the brain therapeutics. Such approaches supposed to circumvent the BBB or have the ability to cross the barrier function and thus increases the drug concentration in the brain. Although the efficacy of novel carrier system depends upon various physiological factors like active efflux transport, protein corona of the brain, stability, and toxicity of the nanocarrier, physicochemical properties, patient-related factors and many more. Hence, to develop a promising carrier system, it is essential to understand the physiology of the brain and BBB and also the other associated factors. Along with this, some alternative route like direct nose-to-brain drug delivery can also offer a better means to access the brain without exposure of the BBB. In this review, we have discussed the role of various physiological barriers including the BBB and blood-cerebrospinal fluid barrier (BCSFB) on the drug therapy and the mechanism of drug transport across the BBB. Further, we discussed different novel strategies for brain targeting of drug including, polymeric nanoparticles, lipidic nanoparticles, inorganic nanoparticles, liposomes, nanogels, nanoemulsions, dendrimers, quantum dots, etc. along with the intranasal drug delivery to the brain. We have also illustrated various factors affecting the drug targeting efficiency of the developed novel carrier system.
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http://dx.doi.org/10.2147/IJN.S210876DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679699PMC
November 2019

Enhanced Biocatalytic Activity of Recombinant Lipase Immobilized on Gold Nanoparticles.

Curr Pharm Biotechnol 2019 ;20(6):497-505

Microbiology and Immunology Department, Faculty of Pharmacy, Mansoura University, Mansoura, Egypt.

Background: Bacterial lipases especially Pseudomonas lipases are extensively used for different biotechnological applications.

Objectives: With the better understanding and progressive needs for improving its activity in accordance with the growing market demand, we aimed in this study to improve the recombinant production and biocatalytic activity of lipases via surface conjugation on gold nanoparticles.

Methods: The full length coding sequences of lipase gene (lipA), lipase specific foldase gene (lipf) and dual cassette (lipAf) gene were amplified from the genomic DNA of Pseudomonas aeruginosa PA14 and cloned into the bacterial expression vector pRSET-B. Recombinant lipases were expressed in E. coli BL-21 (DE3) pLysS then purified using nickel affinity chromatography and the protein identity was confirmed using SDS-PAGE and Western blot analysis. The purified recombinant lipases were immobilized through surface conjugation with gold nanoparticles and enzymatic activity was colorimetrically quantified.

Results: Here, two single expression plasmid systems pRSET-B-lipA and pRSET-B-lipf and one dual cassette expression plasmid system pRSET-B-lipAf were successfully constructed. The lipolytic activities of recombinant lipases LipA, Lipf and LipAf were 4870, 426 and 6740 IUmg-1, respectively. However, upon immobilization of these recombinant lipases on prepared gold nanoparticles (GNPs), the activities were 7417, 822 and 13035 IUmg-1, for LipA-GNPs, Lipf-GNPs and LipAf-GNPs, respectively. The activities after immobilization have been increased 1.52 and 1.93 -fold for LipA and LipAf, respectively.

Conclusion: The lipolytic activity of recombinant lipases in the bioconjugate was significantly increased relative to the free recombinant enzyme where immobilization had made the enzyme attain its optimum performance.
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http://dx.doi.org/10.2174/1389201020666190416144650DOI Listing
October 2019

Enhanced anticancer activity and oral bioavailability of ellagic acid through encapsulation in biodegradable polymeric nanoparticles.

Int J Nanomedicine 2017 10;12:7405-7417. Epub 2017 Oct 10.

Pharmaceutics and Pharmaceutical Technology Department, College of Pharmacy, Taibah University, Al Madina Al Munawara, Saudi Arabia.

Despite the fact that various studies have investigated the clinical relevance of ellagic acid (EA) as a naturally existing bioactive substance in cancer therapy, little has been reported regarding the efficient strategy for improving its oral bioavailability. In this study, we report the formulation of EA-loaded nanoparticles (EA-NPs) to find a way to enhance its bioactivity as well as bioavailability after oral administration. Poly(ε-caprolactone) (PCL) was selected as the biodegradable polymer for the formulation of EA-NPs through the emulsion-diffusion-evaporation technique. The obtained NPs have been characterized by measuring particle size, zeta potential, Fourier transform infrared, differential scanning calorimetry, and X-ray diffraction. The entrapment efficiency and the release profile of EA was also determined. In vitro cellular uptake and cytotoxicity of the obtained NPs were evaluated using Caco-2 and HCT-116 cell lines, respectively. Moreover, in vivo study has been performed to measure the oral bioavailability of EA-NPs compared to free EA, using New Zealand white rabbits. NPs with distinct shape were obtained with high entrapment and loading efficiencies. Diffusion-driven release profile of EA from the prepared NPs was determined. EA-NP-treated HCT-116 cells showed relatively lower cell viability compared to free EA-treated cells. Fluorometric imaging revealed the cellular uptake and efficient localization of EA-NPs in the nuclear region of Caco-2 cells. In vivo testing revealed that the oral administration of EA-NPs produced a 3.6 times increase in the area under the curve compared to that of EA. From these results, it can be concluded that incorporation of EA into PCL as NPs enhances its oral bioavailability and activity.
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http://dx.doi.org/10.2147/IJN.S147740DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5644528PMC
February 2018

Synthesis of silver nanoparticles with antimicrobial and anti-adherence activities against multidrug-resistant isolates from .

J Taibah Univ Med Sci 2017 Aug 24;12(4):291-297. Epub 2017 Apr 24.

Pharmaceutics and Pharmaceutical Technology Department, College of Pharmacy, Taibah University, Almadinah Almunawwarah, KSA.

Objectives: The spread of multidrug-resistant pathogens poses a major health threat. Silver nanoparticles represent a new-class of antimicrobial agents. The aim of this study is the microbial synthesis of silver nanoparticles and the evaluation of their antimicrobial and antibiofilm activities.

Methods: Silver nanoparticles were synthesized using cell free supernatants of . Silver nanoparticles were characterized by particle size analysis and transmission electron microscopy (TEM), and the antimicrobial and antibiofilm activities of the synthesized silver nanoparticles were assessed.

Results: The silver nanoparticle synthesis was monitored primarily by the conversion of the pale yellow colour of the bacteria free supernatants into a dark brown colour. Silver nanoparticles had uniform spherical shape, with particle sizes ranging from 37 to 168 nm and a zeta potential of -11.7 mV. Acinetobacter silver nanoparticles were effective against multidrug-resistant and with minimal inhibitory concentrations of 3.1, 1.56 and 3.1 μg/ml, respectively. Moreover, acinetobacter silver nanoparticles significantly reduced the attachment activities of and by 66.6%, 86.5% and 75%, respectively.

Conclusion: Silver nanoparticles, synthesized from inhibited microbial growth and eradicated biofilm assembly by multidrug-resistant isolates that were derived from uropathogenic infection. These results suggested the possibility of using silver nanoparticles as effective antimicrobial and antibiofilm agents against infections caused by resistant isolates.
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http://dx.doi.org/10.1016/j.jtumed.2017.02.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6694881PMC
August 2017

Formulation of carbapenems loaded gold nanoparticles to combat multi-antibiotic bacterial resistance: In vitro antibacterial study.

Int J Pharm 2017 Jun 11;525(1):71-84. Epub 2017 Apr 11.

Pharmaceutics and Pharmaceutical Technology Department, College of Pharmacy, PO Box 30040, Taibah University, Al-Madinah Al-Munawarah, Saudi Arabia; Microbiology and Immunology Department, Faculty of Pharmacy, Mansoura University, PO Box 35516, Mansoura, Egypt. Electronic address:

Despite the fact that carbapenems (powerful β-lactams antibiotics) were able to fight serious infectious diseases, nowadays the spread of carbapenems-resistant bacteria is considered the main challenge in antibacterial therapy. In this study, we focused on evaluating the surface conjugation of carbapenems (imipenem and meropenem) with gold nanoparticles as a delivering strategy to specifically and safely maximize their therapeutic efficacy while destroying the developing resistance of the pathogens. Different particle size formulae (35, 70 and 200nm) were prepared by citrate reduction method. The prepared nanoparticles were functionalized with imipenem (Ipm) or meropenem (Mem) and physico-chemically characterized for loading efficiency, particle size, morphology, and in-vitro release. The antibacterial efficacy was also evaluated against carbapenems resistant Gram-negative bacteria isolated from infected human, through measuring the minimum inhibitory concentration and antibiotic kill test. All the obtained gold nanoparticles showed a distinct nano-size with loading efficiency up to 72% and 74% for Ipm and Mem, respectively. The conjugation and physico-chemical stability of the formulated carbapenems were confirmed by FTIR and X-RPD. Diffusion driven release behavior was observed for both Ipm and Mem from all of the loaded gold nanoparticles. For both Ipm and Mem, formula with 35nm diameter showed the most significant enhancement in antibacterial activity against all the selected isolates including Klebsiella pneumoniae, Proteus mirabilis and Acinteobacter baumanii. Ipm loaded Gold nanoparticles demonstrated decrease in the MIC of Ipm down to four folds, whereas, Mem loaded gold nanoparticles showed decrease in the MIC of Mem down to three folds on the tested bacterial isolates. Based on these results, the formulation of carbapenems-loaded gold nanoparticles demonstrated to be a promising nano-size delivery vehicle for improving the therapeutic activity and destroying the bacterial resistance for carbapenems.
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http://dx.doi.org/10.1016/j.ijpharm.2017.04.019DOI Listing
June 2017

Imipenem/cilastatin encapsulated polymeric nanoparticles for destroying carbapenem-resistant bacterial isolates.

J Nanobiotechnology 2017 Apr 11;15(1):29. Epub 2017 Apr 11.

Pharmaceutics and Pharmaceutical Technology Department, College of Pharmacy, Taibah University, PO Box 30040, Al Madina, Al Munawara, Saudi Arabia.

Background: Carbapenem-resistance is an extremely growing medical threat in antibacterial therapy as the incurable resistant strains easily develop a multi-resistance action to other potent antimicrobial agents. Nonetheless, the protective delivery of current antibiotics using nano-carriers opens a tremendous approach in the antimicrobial therapy, allowing the nano-formulated antibiotics to beat these health threat pathogens. Herein, we encapsulated imipenem into biodegradable polymeric nanoparticles to destroy the imipenem-resistant bacteria and overcome the microbial adhesion and dissemination. Imipenem loaded poly Ɛ-caprolactone (PCL) and polylactide-co-glycolide (PLGA) nanocapsules were formulated using double emulsion evaporation method. The obtained nanocapsules were characterized for mean particle diameter, morphology, loading efficiency, and in vitro release. The in vitro antimicrobial and anti adhesion activities were evaluated against selected imipenem-resistant Klebsiella pneumoniae and Pseudomonas aeruginosa clinical isolates.

Results: The obtained results reveal that imipenem loaded PCL nano-formulation enhances the microbial susceptibility and antimicrobial activity of imipenem. The imipenem loaded PCL nanoparticles caused faster microbial killing within 2-3 h compared to the imipenem loaded PLGA and free drug. Successfully, PCL nanocapsules were able to protect imipenem from enzymatic degradation by resistant isolates and prevent the emergence of the resistant colonies, as it lowered the mutation prevention concentration of free imipenem by twofolds. Moreover, the imipenem loaded PCL eliminated bacterial attachment and the biofilm assembly of P. aeruginosa and K. pneumoniae planktonic bacteria by 74 and 78.4%, respectively.

Conclusions: These promising results indicate that polymeric nanoparticles recover the efficacy of imipenem and can be considered as a new paradigm shift against multidrug-resistant isolates in treating severe bacterial infections.
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http://dx.doi.org/10.1186/s12951-017-0262-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5387208PMC
April 2017

Synthesis, characterization, molecular modeling, and potential antimicrobial and anticancer activities of novel 2-aminoisoindoline-1,3-dione derivatives.

Bioorg Chem 2016 06 10;66:1-11. Epub 2016 Mar 10.

Pharmaceutics and Pharmaceutical Technology Department, College of Pharmacy, Taibah University, P.O. Box 30039, Al-Madinha Al-Munawaraha 41477, Saudi Arabia; Department of Pharmaceutics, Faculty of Pharmacy, Helwan University, P.O. Box 11795, Cairo, Egypt.

In an effort to establish new drug candidates with improved antimicrobial and anticancer activities, we report here synthesis, molecular modeling, and in vitro biological evaluation of novel substituted N-amino phthalamide derivatives (3a-b, 4a-b, 5a-j, and 6). Structures of the newly synthesized compounds were described by IR, (1)H &(13)CNMR and LC-MS spectral data. The novel compounds were evaluated for their antibacterial activity against four types of Gm+ve and two for Gm-ve types, and antifungal activity against three fungi microorganisms by well diffusion method. Of these novel compounds, Schiff bases showed mostly promising antibacterial activity compared to reference drugs. A successful step was done for explanation of their mode of action through molecular docking of most active molecules at DNA gyrase B enzyme and further were biologically tested. Moreover, the antiproliferative activity was tested against two human carcinoma cell lines (Human colon carcinoma (HCT-116) and human breast adenocarcinoma (MCF-7)) showing promising anticancer activity compared to doxorubicin drug. The data from structure-activity relationship (SAR) analysis revealed that the lypophilic properties of these compounds might be essential parameter for their activity and suggest that 2-amino phthalamide scaffold derivatives 5g and 5h exhibited good antimicrobial and anticancer activities and might used as leads for further optimization.
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http://dx.doi.org/10.1016/j.bioorg.2016.03.003DOI Listing
June 2016

Cellular uptake, cytotoxicity and in-vivo evaluation of Tamoxifen citrate loaded niosomes.

Int J Pharm 2015 Sep 19;493(1-2):285-94. Epub 2015 Jul 19.

Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Helwan University, Cairo, Egypt. Electronic address:

One of the main challenges in Tamoxifen cancer therapy is achieving localized, efficient and sustained delivery without harming normal healthy organs. This study focused on evaluating Tamoxifen Citrate (TMC) niosomes for localized cancer therapy through in-vitro breast cancer cytotoxicity as well as in-vivo solid anti-tumor efficacy. Different niosomal formulae were prepared by film hydration technique and characterized for entrapment efficiency% (E. E), vesicle size, morphology, and in-vitro release. The cellular uptake and anti-cancer activity were also tested in-vitro using MCF-7 breast cancer cell line. Moreover, in-vivo anti-tumor efficacy was examined in Ehrlich carcinoma mice model through reporting solid tumor volume regression and tissue TMC distribution. The obtained niosomes prepared with Span 60: cholesterol (1: 1 molar ratio) showed a distinct nano-spherical shape with EE up to 92.3%± 2.3. Remarkably prolonged release of TMC following diffusion release behavior was detected. The optimized formula showed significantly enhanced cellular uptake (2.8 fold) and exhibited significantly greater cytotoxic activity with MCF-7 breast cancer cell line. In-vivo experiment showed enhanced tumor volume reduction of niosomal TMC when compared to free TMC. Based on these results, the prepared niosomes demonstrated to be promising as a nano-size delivery vehicle for localized and sustained TMC cancer therapy.
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http://dx.doi.org/10.1016/j.ijpharm.2015.07.041DOI Listing
September 2015

Photo-irradiation paradigm: Mapping a remarkable facile technique used for advanced drug, gene and cell delivery.

J Control Release 2015 Nov 13;217:10-26. Epub 2015 Jul 13.

Pharmaceutics & Polymeric Drug Delivery Research Lab (PPDDRL), College of Pharmacy, PO Box 2713, Qatar University, Doha, Qatar.

Undoubtedly, the progression of photo-irradiation technique has provided a smart engineering tool for the state-of-the-art biomaterials that guide the biomedical and therapeutic domains for promoting the modern pharmaceutical industry. Many investigators had exploited such a potential technique to create/ameliorate numerous pharmaceutical carriers. These carriers show promising applications that vary from small drug to therapeutic protein delivery and from gene to living cell encapsulation design. Harmony between the properties of precisely engineered precursors and the formed network structure broadens the investigator's intellect for both brilliant creations and effective applications. As well, controlling photo-curing at the formulation level, through manipulating the absorption of light stimuli, photoinitiator system and photo-responsive precursor, facilitates the exploration of novel distinctive biomaterials. Discussion of utilizing different photo-curing procedures in designing/formulation of different pharmaceutical carriers is the main emphasis of this review. In addition, recent applications of these intelligent techniques in targeted, controlled, and sustained drug delivery with understanding of photo-irradiation concept and mechanism are illustrated.
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http://dx.doi.org/10.1016/j.jconrel.2015.07.005DOI Listing
November 2015

Osmotic-driven release of papaverine hydrochloride from novel poly(decane-co-tricarballylate) elastomeric matrices.

Ther Deliv 2010 Jul;1(1):37-50

School of Pharmacy, Memorial University of Newfoundland, St. John's, NL AIB 3V6, Canada.

Background: We have recently reported on the synthesis, characterization and biocompatibility of a novel family of visible-light photocrosslinked poly(diol-co-tricarballylate) elastomers intended for use in drug delivery and tissue engineering applications. In this work, the osmotic-driven controlled release of the water-soluble drug, papaverine hydrochloride, from poly(decane-co-tricarballylate) elastomeric cylindrical monoliths is reported. We also examined the influence of various parameters such as the degree of prepolymer acrylation, crosslinking density and the incorporation of osmotic excipients such as trehalose on the release kinetics of the drug.

Results: The release rate of papaverine hydrochloride was found to decrease in dissolution media of higher osmotic activity as an indication of the predominant involvement of the osmotic-driven release mechanism from the elastomeric devices. The drug release rate was also found to be dependent on the degree of macromer acrylation. Furthermore, it was found that coformulating papaverine hydrochloride with trehalose increases the release rate without altering the linear nature of the drug release kinetics.

Conclusions: A new delivery vehicle composed of biodegradable poly(decane-co-tricarballylate) elastomers was demonstrated to be a promising and effective matrix for linear, constant and controllable osmotic-driven release of drugs.
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http://dx.doi.org/10.4155/tde.10.2DOI Listing
July 2010

Synthesis, characterization and cytocompatibility of a poly(diol-tricarballylate) visible light photo-cross-linked biodegradable elastomer.

J Biomater Sci Polym Ed 2010 ;21(4):507-28

School of Pharmacy, Memorial University of Newfoundland, St. John's, NF, Canada.

The synthesis, characterization and in vitro cytocompatibility of a new family of photo-cross-linked amorphous poly(diol-tricarballylate) (PDT) biodegradable elastomeric polyesters are reported. The synthesis was based on the polycondensation reaction between tricarballylic acid and alkylene diols, followed by acrylation. The prepared and acrylated poly(diol-tricarballylate) (APDT) was characterized by means of FT-IR, (1)H-NMR, GPC and DSC. Liquid-to-solid photo-curing was carried out by exposing the APDT to visible light in the presence of camphorquinone as a photoinitiator. The thermal properties, mechanical characteristics, sol content, long-term in vitro degradation and cytocompatibility of the prepared PDT elastomers were also reported. The mechanical and degradation properties of this new photocurable elastomer can be precisely controlled by varying the density of acrylate moieties in the matrix of the polymer, and through changes in the pre-polymer chain length. The use of visible light cross-linking, possibility of solventless drug loading, controllable mechanical properties and cytocompatibility of these new elastomers make them excellent candidates for use in controlled implantable drug-delivery systems of protein drugs and other biomedical applications.
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http://dx.doi.org/10.1163/156856209X429157DOI Listing
June 2010

Interleukin-2: evaluation of routes of administration and current delivery systems in cancer therapy.

J Pharm Sci 2009 Jul;98(7):2268-98

School of Pharmacy, Memorial University of Newfoundland, St. John's, Newfoundland, Canada.

Despite the fact that different administration routes and delivery systems have been used for interleukin-2 (IL-2) delivery, little has been reported regarding the most efficient strategies used to deliver IL-2 in a nontoxic, efficient, stable and safe manner. Systemic IL-2 administration has always been associated with rapid clearance and severe toxicity as a result of its narrow therapeutic index. Loco-regional IL-2 delivery, however, is used to localize IL-2 actions and activities into the vicinity of tumors and can result in an improved therapeutic outcome with much less side effects or toxicity. The purpose of this review is to report on the different properties and aspects of IL-2, including its mechanism of action, physicochemical properties, and structure which have an impact on the activity, stability and formulation of IL-2 dosage forms and delivery systems. In addition, advantages and limitations of the currently available techniques and strategies to deliver IL-2 will also be covered.
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http://dx.doi.org/10.1002/jps.21596DOI Listing
July 2009
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