Design and Development of Metformin HCl Mucoadhesive Microcapsules and Design and Evaluation of Alginate Based Mucoadhesive Microcapsules of Metformin HClAuthor(s): D. V. Ramanjaneyulu, C. Surendra Babu, M. Mona Nirupa, M. Mounika, M. Divyasree and S. Bhuvaneswari
In this study, an attempt was made to prepare mucoadhesive microcapsules of metformin HCl using various mucoadhesive polymers designed for oral controlled release. Metformin HCl microcapsules were prepared using sodium alginate and mucoadhesive polymer such as sodium carboxymethyl cellulose (sodium CMC), carbopol 934P or hydroxy propylmethyl cellulose (HPMC) by orifice-ionic gelation method. The microcapsules were evaluated for surface morphology and particle shape by scanning electron microscope. Microcapsules were also evaluated for their microencapsulation efficiency, in vitro wash-off mucoadhesion test, in vitro drug release and in vivo study. The micro capsules were discrete, spherical and free flowing. The microencapsulation efficiency was in the range of 65-80% and microcapsules exhibit good mucoadhesive property in the in vitro wash-off test. The percentage of microcapsules adhering to tissues at pH 7.4 after 6 h varied from 12-32%, whereas the percentage of microcapsules adhering to tissues at pH 1.2 after 6 h varied from 35-65%. The drug release was also found to be slow and extended for more than 16 h. In vivo testing of the mucoadhesive microcapsules in diabetic albino rats demonstrated significant antidiabetic effect of metformin HCl. The hypoglycemic effect obtained by mucoadhesive microcapsules was for more than 16 h whereas metformin HCl produced an antidiabetic effect for only 10 h suggesting that mucoadhesive microcapsules are valuable system for the long term delivery of metformin HCl.