Microencapsulation of indomethacin by complex coacervation of chitosan-carboxymethylcellulose and chitosan-pectin

Abstract

Microcapsule peroral dosage form prepared by complex coacervation technique using aqueous vehicle was developed in order to control drug release. Microcapsules were formed by interaction between positive charge of chitosan and negative charge of carboxymethylcellulose or pectin. Indomethacin, as a model drug, was entrapped in microcapsules. The physicochemical properties of microcapsules such as morphology, shape, size and size distribution, drug entrapment, drug release profiles, infrared spectra and differential scanning calorimetric thermograms were studied, and reproducibility of satisfactory preparations was also investigated. The results showed that polymer concentration affected the formation of microcapsules. In chitosan-pectin microencapsulation, calcium chloride was added to chitosan solution in order to prevent agglomeration of microcapsule droplets. Surface topography of micorcapsules was affected by type of polymer. Microcapsule wall prepared from chitosan-carboxymethylcellulose was smooth and a little wavy while that prepared from chitosan-pectin was rough and heavily wrinkled. Morever, drying process could affect the mean size and size distribution of microcapsules. Size distribution of chitosan-carboxymethylcellulose and chitosan-pectin microcapsules ranged between 40-291 and 40-459 microns, respectively. The drug release profiles showed that the release from both chitosan-carboxymethyl-cellulose and chitosan-pectin microcapsules followed Higuchi's model and could be sustained up to 24 hours depending on concentration of polymer, glutaraldehyde content, and hardening time. Both chitosan-carboxymethylcellulose and chitosan-pectin indomethacin microcapsules could be reproduced