Control of Drug Release Rate by Use of Mixtures of Polycaprolactone and Cellulose Acetate Butyrate Polymers

Chang, Rong‐Kun; Price, James C.; Whitworth, Clyde W.

doi:10.3109/03639048709068375

Cited by 30 publications

(10 citation statements)

References 2 publications

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“…9 Polymer blending has been used as an alternative for tailoring the degradability [10][11][12] and the drug release character of polymers. [13][14][15][16] However, there has been little study on the relationships between the compatibility of polymer blends and their degradability, as well as their controlled drug release behavior. The compatibility of a blend affects the crystallinity and physical properties; therefore, it may influence the degradation and the controlled release properties of the blend.…”

Section: Introductionmentioning

confidence: 99%

Regulation of biodegradability and drug release behavior of aliphatic polyesters by blending

Shen

Sun

Zhu

et al. 2000

J. Biomed. Mater. Res.

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Polyester blending of poly(epsilon-caprolactone) (PCL) with poly(D, L-lactide) (PLA) and their random copolymers (R(CL/LA)) was found to be a convenient approach to regulate the degradation and drug release behaviors of the polyesters. The blend composition and compatibility both affected its degradation and drug release behavior. A DSC study showed that PCL was compatible with 50:50 poly(CL-CO-D,L-LA) (R(50/50)) but incompatible with 25:75 poly(CL-CO-LA) (R(25/75)) and PLA homopolymer. The hydrolysis experiments indicated that with the same CL/LA segment proportion, compatible blends (PCL/R(50/50)) had higher water content and faster weight loss than incompatible blends (PCL/PLA, PCL/R(25/75)). In the compatible blends the PCL degradation rate was increased while that of R(50/50) was decreased. The controlled release kinetics, diffusion constants, and permeation coefficients of the polymer blends were measured by using northindrone (NTD) as a model. The NTD release rates from the polyester blends increased as the CL unit fraction increased but decreased with increasing the LA unit fraction in the blends. With the same CL/LA unit ratios, the NTD release rate from the compatible blend was slower than that from the incompatible blend. The NTD release from the polyester blend was controlled by the diffusion process in the early stage, but the degradation-caused NTD release was later involved. By tailoring the blend composition to such an extent that the degradation-caused release compensated the decline of the diffusion-caused release, a zero-order NTD release was achieved.

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Section: Introductionmentioning

confidence: 99%

Regulation of biodegradability and drug release behavior of aliphatic polyesters by blending

Shen

Sun

Zhu

et al. 2000

J. Biomed. Mater. Res.

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“…Microcapsules containing glipizide were also generated employing alginate and CP to form a homogeneous polymer mixture, which was significantly better than an individual polymer for achieving extended release[2526]. Pellets containing CP usually form a thin gel-barrier in dissolution medium that led to less penetration of medium liquid into the pellets[27–30].…”

Section: Resultsmentioning

confidence: 99%

Microencapsulation approach for orally extended delivery of glipizide: In vitro and in vivo evaluation

Abdelbary¹,

Na²,

Hosny³

2012

Indian J Pharm Sci

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Glipizide is an effective antidiabetic agent, however, it suffers from relatively short biological half-life. To solve this encumbrance, it is a prospective candidate for fabricating glipizide extended release microcapsules. Microencapsulation of glipizde with a coat of alginate alone or in combination with chitosan or carbomer 934P was prepared employing ionotropic gelation process. The prepared microcapsules were evaluated in vitro by microscopical examination, determination of the particle size, yield and microencapsulation efficiency. The filled capsules were assessed for content uniformity and drug release characteristics. Stability study of the optimised formulas was carried out at three different temperatures over 12 weeks. In vivo bioavailability study and hypoglycemic activity of C9 microcapsules were done on albino rabbits. All formulas achieved high yield, microencapsulation efficiency and extended t1/2. C9 and C19 microcapsules attained the most optimised results in all tests and complied with the dissolution requirements for extended release dosage forms. These two formulas were selected for stability studies. C9 exhibited longer shelf-life and hence was chosen for in vivo studies. C9 microcapsules showed an improvement in the drug bioavailability and significant hypoglycemic activity compared to immediate release tablets (Minidiab® 5 mg). The optimised microcapsule formulation developed was found to produce extended antidiabetic activity.

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“…These results may be explained by the reduced emulsification efficiency (rate of agitation) consecutive to higher medium viscosity thereby leading to larger droplets (protomicroparticles). In fact, even if controlled largely by the rate of agitation, particle size is also dependent on the viscosity, interfacial tension, and density of microparticle materials 47. However all other parameters remaining empirically the same, it was postulated that increasing the M W of the PCL led to an increase in the viscosity of the organic phase, which reduced protein diffusion into the external aqueous phase before microparticles hardening 6, 48.…”

Section: Resultsmentioning

confidence: 99%

Influence of protein content on the physicochemistry of poly(ϵ‐caprolactone) microparticles

Youan

2006

J of Applied Polymer Sci

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ABSTRACT:The aim of this work was to determine the influence of protein content on the physicochemical properties of protein-loaded poly(-caprolactone) (PCL). To achieve this goal, bovine serum albumin (BSA), an example of protein was encapsulated within PCL matrix by emulsion solvent evaporation method. The polymer matrix's rheological properties, hydrophobicity, molecular weight (M W ), and thermal behavior were determined. Particle characteristics such as BSA loading, surface area, mean size, morphology, and in vitro release profile were also assessed. After encapsulation process, the polymer crystallinity and crystallization point were markedly increased suggesting that a nucleation phenomenon occurred. The increase in PCL M W (from 46. 7 to 179.4 kDa) led to an increase of both particle size and encapsulation efficiency that was consistent with rheological data. The increase of protein content from 1.6 to 11.5% (w/w) influenced considerably particle's specific surface area and decreased the rate of protein release. Together, these results suggest that beside the nature of the carrier polymer, protein content may have implication on their controlled release, the coating of particle by protein, and on the carrier polymer chemistry and degradation.

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Control of Drug Release Rate by Use of Mixtures of Polycaprolactone and Cellulose Acetate Butyrate Polymers

Cited by 30 publications

References 2 publications

Regulation of biodegradability and drug release behavior of aliphatic polyesters by blending

Regulation of biodegradability and drug release behavior of aliphatic polyesters by blending

Microencapsulation approach for orally extended delivery of glipizide: In vitro and in vivo evaluation

Influence of protein content on the physicochemistry of poly(ϵ‐caprolactone) microparticles

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