Effect of drug loading extent on the in vitro release kinetic behaviour of nifedipine from polyacrylate microspheres

S. Benita*, A. Barkai, Y. V. Pathak

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

Nifedipine-loaded polyacrylate microspheres were prepared using a solvent evaporation process. The analysis of the nifedipine release profiles as a function of the process variables revealed that the organic phase viscosity increase did not affect significantly the nifedipine release profile. In contrast, increasing the drug concentration decreased the release rate from the microspheres as a result of formation of nifedipine crystalline domains in the microspheres with increasing drug contents. It was found that all the global release profiles yielded by the nifedipine microspheres at low loading conformed with desorption kinetics of a dissolved drug from a monolithic spherical device. At intermediate and higher nifedipine payloads, it was not possible to identify any kinetic model. This is probably due to drug-polymer interactions that would account for the deviation of nifedipine release profile from the expected Higuchi diffusional model of dispersed drug particles in spherical micromatrices. Furthermore, these drug release profiles were quite similar to the dissolution profile of pure nifedipine crystals, suggesting that the drug release from the highly loaded microspheres is governed by the dissolution rate of the nifedipine crystalline domains in the microspheres.

Original languageEnglish
Pages (from-to)213-222
Number of pages10
JournalJournal of Controlled Release
Volume12
Issue number3
DOIs
StatePublished - May 1990

Keywords

  • Eudragit polyacrylate
  • microspheres
  • nifedipine
  • release kinetics

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