Abstract

Olibanum resin was evaluated as microencapsulating agent and to prepare resin-coated microcapsules. Resin-coated microcapsules of nifedipine were prepared by an industrially feasible emulsification-solvent evaporation method and the microcapsules were investigated. The resin-coated microcapsules are spherical, discrete, free-flowing and multinucleate monolithic type. Microencapsulation efficiency was in the range 98-105%. Nifedipine release from the resin-coated microcapsules was slow over 24 h and depended on core: coat ratio, wall thickness and size of the microcapsules. Drug release was by non-fickian diffusion mechanism. Good linear relationships were observed between wall thickness of the microcapsules and release rate and T50 values. Resin-coated microcapsules of nifedipine exhibited good controlled release characteristics and were found suitable for once a day oral controlled release products.