Preparation and Evaluation of Mucoadhesive Microcapsules of Flurbiprofen for Oral Controlled Release

The objective of this study was to develop, characterize and evaluate mucoadhesive microcapsules of flurbiprofen with a coat consisting of sodium alginate in combination with other mucoadhesive polymers such as sodium carboxy methylcellulose (sodium CMC), methyl cellulose (MC), carbopol and hydroxy propyl methyl cellulose (HPMC) by an emulsification-ionic gelation process for prolonged gastrointestinal absorption. The microcapsules were prepared by an emulsification-ionic gelation process. The microcapsules were evaluated for physical characteristics such as particle size, particle shape and surface morphology by scanning electron microscopy, and other parameters like drug entrapment efficiency, in vitro mucoadhesion by everted intestinal sac technique and in vitro drug release characteristics. The USP Rotating Basket method was selected to perform the dissolution profiles carried out in 900 ml of phosphate buffer of pH 7.2. The resulting microcapsules were discrete, small, and fairly spherical and free flowing. Microencapsulation efficiency was 60.92% to 87.74% and relatively high with alginate-carbopol and low with alginate-MC combinations. On the contrary, alginate-carbopol shown lower strength of mucoadhesion and high percentage of mucoadhesion was observed with alginate-MC combination. Flurbiprofen release from these mucoadhesive microcapsules was slow, extended over longer periods of time and depended on the combination of mucoadhesive polymer. The highest percentage of drug release was observed with alginate-hydroxy propyl methyl cellulose. Drug release kinetics from these formulations corresponded best to Higuchi model. The release of the model drug from these mucoadhesive microcapsules was prolonged over an extended period of time and the drug release mechanism followed anomalous (non- Fickian) diffusion controlled as well as Case II transport. By providing intimate contact of dosage form with the absorbing surface, bioavailability of drug could enhanced which in turn improves pharmacological effect. As a result, oral controlled release dosage form to avoid serious gastrointestinal adverse effects commonly associated with the model drug was achieved by the principle of mucoadhesion.