Effect of formulation and processing factors on the characteristics of biodegradable microcapsules of zidovudine.

Biodegradable microcapsules of zidovudine (AZT) were prepared using poly-(lactide/glycolide) by the solvent evaporation technique. The objective of this project was to focus on the effect of several formulation and processing factors on the efficiency of encapsulation, surface morphology, and drug release profiles. When the drug was incorporated as powder or as aqueous suspension containing a high amount of insoluble particles, to the organic phase the surface of the microcapsules was appeared to be wrinkled. The efficiency of encapsulation decreased when AZT powder was dispersed directly into the organic solvent instead of adding as an aqueous solution. When the relative volume of the aqueous phase containing 1% PVA was changed from 25 up to 125% of the volume of the organic phase, the efficiency of encapsulation, surface morphology, and release profiles did not change significantly. The efficiency of encapsulation decreased from 9 to 3.8% when the drug loading was increased from 10 to 50% of the weight of the polymer.

[1]  T. Mandal,et al.  Preparation of biodegradable microcapsules containing zidovudine (AZT) using solvent evaporation technique. , 1996, Journal of microencapsulation.

[2]  R. Langer,et al.  Formulation and Delivery of Proteins and Peptides. Design and Development Strategies. , 1995 .

[3]  R. Jerome,et al.  Effect of the emulsion stability on the morphology and porosity of semicrystalline poly l-lactide microparticles prepared by w/o/w double emulsion-evaporation , 1994 .

[4]  J. Resau,et al.  Characterization and morphological analysis of protein-loaded poly(lactide-co-glycolide) microparticles prepared by water-in-oil-in-water emulsion technique , 1994 .

[5]  K. Avgoustakis,et al.  Biodegradable controlled release tablets: II. Preparation and properties of poly(lactide-co-glycolide) powders , 1993 .

[6]  K. Avgoustakis,et al.  Biodegrable controlled release tablets: III. Effect of polymer characteristics on drug release from heterogeneous poly(lactide-co-glycolide) matrices , 1993 .

[7]  R. Jerome,et al.  Microencapsulation by coacervation of poly(lactide‐co‐glycolide)—II: Encapsulation of a dispersed aqueous phase , 1993 .

[8]  P. Sansdrap,et al.  Influence of manufacturing parameters on the size characteristics and the release profiles of nifedipine from poly(DL-lactide-co-glycolide) microspheres , 1993 .

[9]  K. Zhu,et al.  Blends of PVA and PGLA: control of the permeability and degradability of hydrogels by blending , 1992 .

[10]  James M. Anderson,et al.  Biocompatibility studies of naltrexone sustained release formulations , 1992 .

[11]  J. Benoit,et al.  In vivo peptide release from poly(dl-lactic acid-co-glycolic acid) copolymer 5050 microspheres , 1991 .

[12]  R. Arshady,et al.  Microspheres and microcapsules, a survey of manufacturing techniques: Part III: Solvent evaporation , 1990 .

[13]  R. Bodmeier,et al.  Encapsulation of water-soluble drugs by a modified solvent evaporation method. I. Effect of process and formulation variables on drug entrapment. , 1990, Journal of microencapsulation.

[14]  R. Langer,et al.  Biodegradable polymers as drug delivery systems , 1990 .

[15]  R. Bodmeier,et al.  The effect of the addition of low molecular weight poly(dl-lactide) on drug release from biodegradable poly(dl-lactide) drug delivery systems , 1989 .

[16]  D. Negi,et al.  Preparation and characterization of poly(styrene) microcapsules containing corrosion inhibitors. , 1989, Journal of microencapsulation.

[17]  H. Okada,et al.  Controlled-release of leuprolide acetate from polylactic acid or copoly(lactic/glycolic) acid microcapsules: influence of molecular weight and copolymer ratio of polymer. , 1988, Chemical & pharmaceutical bulletin.

[18]  C. X. Song,et al.  Microspheres of Biodegradable Block Copolymer for Long-Acting Controlled Delivery of Contraceptives , 1987 .