PREPARATION AND EVALUATION OF HPMC-ALGINATE MUCOADHESIVE MICROCAPSULES OF DICLOFENAC FOR CONTROLLED RELEASE

A new, novel promising technology for obtaining controlled release and enhancing the bioavailability is a combination of mucoadhesion principle and microencapsulation to result in mucoadhesive microcapsules. Mucoadhesive microcapsules consist of either entirely of a mucoadhesive polymer or having an outer coating enclosing the drug particles. They facilitate an intimate and prolonged contact with the absorption surface to provide controlled release and enhanced bioavailability of the contained drug over longer period of time to prolong its therapeutic action. The objective of the present work is to prepare HPMC based mucoadhesive microcapsules of diclofenac and to evaluate the microcapsules for mucoadhesiveness and controlled drug release characteristics. Spherical HPMC-alginate mucoadhesive micro- capsules of diclofenac could be prepared by the orifice – ionic gelation method. Microencapsulation efficiency was in the range 98.7 % – 103.5 %. Drug release from the HPMC – alginate microcapsules was slow and spread over a period of 12 h and depended on core: coat ratio and wall thickness of the microcapsules. Drug release mechanism from these microcapsules was by non- Fickian diffusion.  Good linear relationships were observed between wall thickness of the microcapsules and release rate [K₀ and K₁] of the microcapsules. Mucoadhesion testing by in vitro wash-off test indicated good mucoadhesive property of HPMC-alginate microcapsules with a slower wash-off when compared to non-mucoadhesive EVA microcapsules. Thus controlled release mucoadhesive microcapsules of diclofenac could be designed employing HPMC-alginate. HPMC-alginate microcapsules of diclofenac exhibited good mucoadhesion and controlled release characteristics and were found suitable for oral controlled release of diclofenac.