Preparation and evaluation of ethyl cellulose coated microcapsules of carbamazepine for controlled release

The objective of the study is to prepare and evaluate ethyl cellulose coated microcapsules of carbamazepine for controlled release. Ethyl cellulose microcapsules of carbamazepine were prepared by an industrially feasible emulsification-solvent evaporation method and evaluated for controlled release. These microcapsules were spherical, discrete, free flowing and multi nucleate monolithic type. Microencapsulation efficiency was in the range 80-95 %. Carbamazepine release from the microcapsules was slow over 24 h and depended oil core:coat ratio, wall thickness and size of the microcapsules and was by Fickian diffusion mechanism. Good linear relationship was observed between wall thickness of the microcapsules and release rate. Ethyl cellulose was found suitable as a microencapsulating agent for carbamazepine and Such microcapsules MC2 (size 20/30) exhibited good controlled release characteristics, fulfilling the official (USP 30) release requirement prescribed for carbamazepine extended release tablets and these microcapsules were found suitable for once daily administration of carbamazepine.