SUSTAINED RELEASE MUCOADHESIVE MICROCAPSULES OF RAMIPRIL BY IONIC GELATION TECHNIQUE: FORMULATION DESIGN, OPTIMIZATION AND CHARACTERIZATION

Abstract

Objective: The major objective of the research work was to design, optimise and characterise sodium alginate based sustained release mucoadhesive microcapsules of ramipril by ionic gelation method. Methods: An experimental set-up was designed to investigate the optimal combination of mucoadhesive polymers such as carbopol 974P, HPMC (K4M and K100M), Na CMC and chitosan and their drug compatibility with respect to reliabilities. Preliminary screening of the formulation variables was accomplished by Taguchi design followed by Box-Behnken design for systematic optimisation. The suitable mathematical model was selected, response surface analysis was performed and optimised formulation was chosen by numerical optimization and desirability function method. Characterization of the prepared microcapsules for several inherent properties like particle size, drug content, sphericity, entrapment efficiency, loose surface crystal study, swelling index, micromeritic properties, moisture content, in vitro drug release, mucoadhesive strength and in vivo antihypertensive activity was performed. Results: Differential Scanning Calorimetry (DSC) thermograms and Fourier Transform Infra-Red (FT-IR) spectral studies revealed no incompatibility between the pure drug and selected polymers. The spherical nature of the prepared microcapsules was established by surface morphology studies. Conclusion: The resultant sustained release mucoadhesive microcapsules of ramipril remained stable when subjected to stress conditions unveiling it as a better alternative delivery system with superior therapeutic efficacy.