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MICROPARTICLES: AN APPROACH FOR BETTERMENT OF DRUG DELIVERY SYSTEM  [cached]
Abhay N. Padalkar
International Journal of Pharmaceutical Research and Development , 2011,
Abstract: Recent drug discovery using advanced techniques such as genomics, combinatorial chemistry, high throughput screening and in silico three dimensional drug design has yielded drug candidates with low water solubility and thus an inherently low mucosal permeability which makes the development of pharmaceutical formulations difficult. To overcome these, particulate systems like microparticles have been used as a physical approach to alter and improve the pharmacokinetic and pharmacodynamics properties of various types of drug molecules. They have been used in vivo to protect the drug entity in the systemic circulation, restrict access of the drug to the chosen sites and to deliver the drug at a controlled and sustained rate to the site of action. Various polymers have been used in the formulation of microparticles for drug delivery research to increase therapeutic benefit, while minimizing side effects. The review embraces various aspects of microparticle formulations, characterization, effect of their characteristics and their applications in delivery of drug molecules and therapeutic genes.
Chitosan Microparticles Prepared by the Water-in-Oil Emulsion Solvent Diffusion Method for Drug Delivery  [PDF]
T. Phromsopha,Y. Baimark
Biotechnology , 2010,
Abstract: In the present study biodegradable microparticles of chitosan were prepared by the simple water-in-oil emulsion solvent diffusion method for use as drug delivery systems. Aqueous chitosan solution and ethyl acetate were used as water and oil phases, respectively. Gentamicin sulphate was used as a hydrophilic model drug. Effects of drug content and sodium tripolyphosphate cross-linker on chitosan microparticles and drug release behaviors were investigated. The both drug-free and drug-loaded chitosan microparticles were deflated microparticles and porous structures with 200-400 μm in size. The cross-linking did not affect on microparticle shape and size. The drug release rates decreased as the drug content decreased and the amount of cross-linker increased.
Laser Plasma Jet Driven Microparticles for DNA/Drug Delivery  [PDF]
Viren Menezes, Yohan Mathew, Kazuyoshi Takayama, Akira Kanno, Hamid Hosseini
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050823
Abstract: This paper describes a microparticle delivery device that generates a plasma jet through laser ablation of a thin metal foil and uses the jet to accomplish particle delivery into soft living targets for transferring biological agents. Pure gold microparticles of 1 μm size were coated with a plasmid DNA, pIG121Hm, and were deposited as a thin layer on one surface of an aluminum foil. The laser (Nd:YAG, 1064 nm wavelength) ablation of the foil generated a plasma jet that carried the DNA coated particles into the living onion cells. The particles could effectively penetrate the target cells and disseminate the DNA, effecting the transfection of the cells. Generation of the plasma jet on laser ablation of the foil and its role as a carrier of microparticles was visualized using a high-speed video camera, Shimadzu HPV-1, at a frame rate of 500 kfps (2 μs interframe interval) in a shadowgraph optical set-up. The particle speed could be measured from the visualized images, which was about 770 m/s initially, increased to a magnitude of 1320 m/s, and after a quasi-steady state over a distance of 10 mm with an average magnitude of 1100 m/s, started declining, which typically is the trend of a high-speed, pulsed, compressible jet. Aluminum launch pad (for the particles) was used in the present study to make the procedure cost-effective, whereas the guided, biocompatible launch pads made of gold, silver or titanium can be used in the device during the actual clinical operations. The particle delivery device has a potential to have a miniature form and can be an effective, hand-held drug/DNA delivery device for biological applications.
Magnetically retainable microparticles for drug delivery to the joint: efficacy studies in an antigen-induced arthritis model in mice
Nicoleta Butoescu, Christian A Seemayer, Gaby Palmer, Pierre-André Guerne, Cem Gabay, Eric Doelker, Olivier Jordan
Arthritis Research & Therapy , 2009, DOI: 10.1186/ar2701
Abstract: Microparticles (1 or 10 μm) containing both superparamagnetic iron oxide nanoparticles (SPIONs) and dexamethasone 21-acetate (DXM) were prepared. In a preliminary study, we compared the persistence of microparticles of both sizes in the joint. A second study evaluated the influence of a subcutaneously implanted magnet near the knee on the retention of magnetic microparticles in the joint by in vivo imaging. Finally, the efficacy of 10-μm microparticles was investigated using a model of antigen-induced arthritis (AIA) in mice. Phosphate-buffered saline, DXM suspension, SPION suspension, blank microparticles and microparticles containing only SPIONs were used as controls. Arthritis severity was assessed using 99mTc accumulation and histological scoring.Due to their capacity of encapsulating more corticosteroid and their increased joint retention, the 10-μm microparticles were more suitable vectors than the 1-μm microparticles for corticosteroid delivery to the joint. The presence of a magnet resulted in higher magnetic retention in the joint, as demonstrated by a higher fluorescence signal. The therapeutic efficacy in AIA of 10-μm microparticles containing DXM and SPIONs was similar to that of the DXM suspension, proving that the bioactive agent is released. Moreover, the anti-inflammatory effect of DXM-containing microparticles was more important than that of blank microparticles or microparticles containing only SPIONs. The presence of a magnet did not induce a greater inflammatory reaction.This study confirms the effectiveness of an innovative approach of using magnetically retainable microparticles as intra-articular drug delivery systems. A major advantage comes from a versatile polymer matrix, which allows the encapsulation of many classes of therapeutic agents (for example, p38 mitogen-activated protein kinase inhibitors), which may reduce systemic side effects.The undeniable clinical efficacy of intra-articular (i-a.) corticosteroid injections is somehow restr
An integrated experimental and modeling approach to propose biotinylated PLGA microparticles as versatile targeting vehicles for drug delivery
Olivia Donaldson, Zuyi Jacky Huang and Noelle Comolli
Progress in Biomaterials , 2013, DOI: 10.1186/2194-0517-2-3
Abstract: Polymeric microparticles with covalently attached biotin are proposed as versatile targeting vehicles for drug delivery. The proposed microparticles made of 85/15 poly (lactic-co-glycolic acid) (PLGA) will have biotin available on the outside of the particle for the further attachment with an avidin group. Taking advantage of biotin's high affinity for avidin, and avidin's well-known chemistry, the particle has the potential to be easily coated with a variety of targeting moieties. This paper focuses on the design and resulting effect of adding biotin to PLGA microparticles using an integrated experimental and modeling approach. A fluorescent-tagged avidin (488-streptavidin) was used to confirm the presence and bioavailability of biotin on the outside of the particles. For the purpose of this study, bovine serum albumin (BSA) was used as a model therapeutic drug. Microparticles were created using two different types of polyvinyl alcohol 88 and 98 mol% hydrolyzed, which were then analyzed for their size, morphology, and encapsulation capacity of BSA. Release studies performed in vitro confirmed the slow release of the BSA over a 28-day period. Based on these release profiles, a release kinetics model was used to further quantify the effect of biotinylation of PLGA microparticles on their release characteristics by quantitatively extracting the effective drug diffusivity and drug desorption rate from the release profiles. It was found that the biotinylation of the PLGA microparticles slowed down both the drug desorption and drug diffusion process, which confirmed that biotinylated PLGA microparticles can be used for controlled drug release. The presented technology, as well as the proposed integrated experimental and modeling approach, forms a solid foundation for future studies using a cell-specific ligand that can be attached to avidin and incorporated onto the microparticles for targeted delivery.
Injectable In Situ Forming Microparticles: A Novel Drug Delivery System
EA Yapar, nal, Y zkan, T Baykara
Tropical Journal of Pharmaceutical Research , 2012,
Abstract: Pharmaceutical formulation research has recently been focusing on delivery systems which provide long therapeutic effects and reduced side effects, and involving simplified production stages and facilitated application process. In situ forming microparticle (ISM) systems, one of the latest approach in this field, offer a new encapsulation technique and meet the objectives stated above. Factors such as the carrier used to form the multiparticles, amount and type of drug and the vehicle type can be taken as the main performance criteria for these systems. Ongoing studies have shown that this new multiparticulate drug delivery system is suitable for achieving new implant delivery system with low risk of dose-dumping, capable of being modulated to exhibit varying release patterns, reproducible, easily applicable and welltolerated compared with classically surgical implants.
Evaluation of potential of Zn-pectinate gel (ZPG) microparticles containing mesalazine for colonic drug delivery
J Kawadkar,K Chauhan Meenakshi,A Ram
DARU : Journal of Pharmaceutical Sciences , 2010,
Abstract: "n "n Background and the purpose of the study:Pectin derivatives have been utilized for colonic drug delivery (CDD). In this study the effects of different formulation variables upon the characteristics of pectinate microparticles (MPs) prepared by ionotropic gelation technique for colonic delivery of mesalazine was investigated. "n "nMethods: In-vitro drug release of MPs was studied using USP XXIV dissolution apparatus type I, in different fluids e.g. simulated gastric fluid (SGF: pH 1.2), simulated intestinal fluid (SIF: pH 7.4), and simulated colonic fluid (SCF: pH 6.8) of volume 900 ml, at 100 rpm maintained at 37 ± 0.2 °C. This study was also performed in the presence of 4% w/v rat caecal content (RCC) using phosphate buffer saline (pH 6.8) as SCF. Gamma scintigraphy study was performed on New Zealand rabbit animal model using 99m Tc. "nResults: The results showed that maximum entrapment of mesalazine (86.1 ± 1.7 %) and strength of gel network zinc pectinate gel microparticles (ZPGD2) was achieved in cross-linking solution of pH 1.6. Batch of ZPGD2 showed least swelling ratio and drug release. In RCC medium the t50% value of CPG-MPs was 3-4 folds greater than ZPG-MPs. Scintigram showed the residence of ZPG-MPs (filled in enteric coated capsule) in colon more than 9 hrs and delivery of almost all the drug loading dose in colon. "nMajor conclusion:The results of this study suggest the designed formulation of ZPG-MPs has the potential to serve as a colonic drug delivery system.
Surface morphology of spray-dried nanoparticle-coated microparticles designed as an oral drug delivery system
Beck, R. C. R.;Lionzo, M. I. Z.;Costa, T. M. H.;Benvenutti, E. V.;Ré, M. I.;Gallas, M. R.;Pohlmann, A. R.;Guterres, S. S.;
Brazilian Journal of Chemical Engineering , 2008, DOI: 10.1590/S0104-66322008000200016
Abstract: this paper was devoted to studying the influence of coating material (nanocapsules or nanospheres), drug model (diclofenac, acid or salt) and method of preparation on the morphological characteristics of nanoparticle-coated microparticles. the cores of microparticles were obtained by spray drying or evaporation and the coating was applied by spray drying. sem analyses showed nanostructures coating the surface of nanocapsule-coated microparticles and a rugged surface for nanosphere-coated microparticles. the decrease in their surface areas was controlled by the nanoparticulated system, which was not dependent on microparticle size. optical microscopy and x-ray analyses indicated that acid diclofenac crystals were present in formulations prepared with the acid as well as in the nanocapsule-coated microparticles prepared with the salt. the control of coating is dependent on the use of nanocapsules or nanospheres and independent of either the characteristics of the drug or the method of preparing the core.
Formulation and Evaluation of Glutaraldehyde-Crosslinked Chitosan Microparticles for the Delivery of Ibuprofen
KC Ofokansi, FC Kenechukwu, AB Isah, EL Okigbo
Tropical Journal of Pharmaceutical Research , 2013,
Abstract: Tropical Journal of Pharmaceutical Research is indexed by Science Citation Index (Purpose: Toformulate glutaraldehyde-cross-linked chitosan-based microparticles and evaluate its suitability for the delivery of ibuprofen, a BCS class II drug. Methods: Ibuprofen-loaded chitosan microparticles were prepared by emulsification-cross-linking technique using glutaraldehyde saturated toluene (GST) as the cross-linking agent. The microparticles were characterized with respect to morphology, particle size, microparticle yield and entrapment efficiency. The swelling behaviour of the particles and ibuprofen release were assessed in both simulated gastric fluid (SGF) without pepsin (pH 1.2) and simulated intestinal fluid (SIF) without pancreatin (pH 7.4). Results: Discrete and free-flowing microparticles of size range 100.05 ± 8.82 to 326.70 ± 10.43 ìm were obtained. The microparticles had a high yield (69.2 to 99.2 %) and exhibited greater water sorption capacity in SIF (122.2 %) than in SGF (60 %). Furthermore, the microparticles cross-linked with 10 ml of GST entrapped the highest amount of drug (23.32 ± 0.97 %) while those cross-linked with 25 ml GST had the highest yield of the microparticles (99.19 % ), and highest water sorption in SIF (122.2 %). Up to 93.6 % of the entrapped drug was released in SIF from microparticles cross-linked with 25 ml of GST. Drug release from microparticles cross-linked with 20 and 30 ml each of GST showed a biphasic pattern. Conclusions: Entrapment of ibuprofen in glutaraldehyde-cross-linked chitosan microparticles can be exploited to target and control the release of the drug and possibly reduce its gastro-erosive side effects.
Microencapsulation of nanoemulsions: novel Trojan particles for bioactive lipid molecule delivery
Li X, Anton N, Ta TMC, Zhao M, Messaddeq N, Vandamme TF
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S20353
Abstract: roencapsulation of nanoemulsions: novel Trojan particles for bioactive lipid molecule delivery Original Research (5059) Total Article Views Authors: Li X, Anton N, Ta TMC, Zhao M, Messaddeq N, Vandamme TF Published Date June 2011 Volume 2011:6 Pages 1313 - 1325 DOI: http://dx.doi.org/10.2147/IJN.S20353 Xiang Li1, Nicolas Anton1, Thi Minh Chau Ta1, Minjie Zhao2, Nadia Messaddeq3, Thierry F Vandamme1 1University of Strasbourg, Faculty of Pharmacy, UMR CNRS 7199 Laboratory of Conception and Application of Bioactive Molecules (Biogalenic Pharmacy team); 2University of Strasbourg, Faculty of Pharmacy, CNRS UMR 7178, IPHC, Laboratory of Analytic Chemistry and Food Science; 3Institute of Genetics and Molecular and Cellular Biology (IGBMC), UMR University of Strasbourg/CNRS/INSERM/Collège de France, Illkirch, France Background: Nanoemulsions consist of very stable nanodroplets of oil dispersed in an aqueous phase, typically below 300 nm in size. They can be used to obtain a very fine, homogeneous dispersion of lipophilic compounds in water, thus facilitating their handling and use in nanomedicine. However, the drawback is that they are suspended in an aqueous media. This study proposes a novel technique for drying lipid nanoemulsion suspensions to create so-called Trojan particles, ie, polymer microparticles (around 2 μm) which very homogeneously “entrap” the nano-oil droplets (around 150 nm) in their core. Methods: Microencapsulation of the nanoemulsions was performed using a spray-drying process and resulted in a dried powder of microparticles. By using a low-energy nanoemulsification method and relatively gentle spray-drying, the process was well suited to sensitive molecules. The model lipophilic molecule tested was vitamin E acetate, encapsulated at around 20% in dried powder. Results: We showed that the presence of nanoemulsions in solution before spray-drying had a significant impact on microparticle size, distribution, and morphology. However, the process itself did not destroy the oil nanodroplets, which could easily be redispersed when the powder was put back in contact with water. High-performance liquid chromatography follow-up of the integrity of the vitamin E acetate showed that the molecules were intact throughout the process, as well as when conserved in their dried form. Conclusion: This study proposes a novel technique using a spray-drying process to microencapsulate nanoemulsions. The multiscale object formed, so-called Trojan microparticles, were shown to successfully encapsulate, protect, and release the lipid nanodroplets.
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