Preparation and Characterization of Valsartan Loaded Alginate Mucoadhesive Microcapsules

Sustained release alginate microcapsules of valsartan were prepared by orifice-ionic gelation method using Hydroxy Propyl Methyl Cellulose, (viz, 50 cps, K4M) as mucoadhesive polymer. Microcapsules were discrete spherical and free flowing. Encapsulation efficiency varied from 68.42% to 85.46%. Microcapsules were evaluated for % yield, drug content uniformity, particle size distribution, surface morphology(scanning electron microscopy), percentage moisture loss, in vitro drug release profile, and mucoadhesion study by in vitro wash off test, short term stability ,and drug excipients interactions (DSC and IR spectroscopy). The formulation prepared by using alginate - Hydroxy propyl methyl cellulose (K4M) in the ratio of 5:1 along with magnesium stearate, emerged as the overall best formulation based upon their drug release characteristics (in phosphate buffer 6.8). This formulation showed slow release up to 12 hrs. In vitro drug release followed first order kinetics, fickian diffusion mechanism (n<0.5) and the results had proven the release of the best formulation had extended up to 12 hrs according to t50%, t70% and t90% and the values. All the microcapsules exhibited good mucoadhesive property in the in -vitro wash off test. Accelerated stability studies were carried out for short term studies of formulations according to ICH and Q 1 A (R2) guidelines. These mucoadhesive microcapsules are thus suitable for oral controlled release of valsartan.