Statistical optimization and in-vitro evaluation of hollow microcapsules of an anti-hypertensive agent.

The present work attempts to formulate and evaluate hollow microcapsules of an antihypertensive drug--ramipril, which will remain in vicinity of absorption site. The emulsion diffusion solvent evaporation method was employed for preparation of microspheres using Eudragit E100. Glycerol monostearate and sodium lauryl sulfate were used as surfactants, which showed good effect of film integrity. The different proportion of Eudragit E100 and ramipril at varying speed were employed for formulating hollow microspheres using 3(2) full factorial design. The formulated microspheres were subjected to evaluation of various parameters such as particle size analysis using motic microscope, drug loading efficiency and in vitro drug release. The main effect plot showed negative impact of polymer concentration and drug complex concentration, whereas positive impact of rotation speed on the % release of drug and drug encapsulation efficiency. The optimized batch of microcapsules was formulated as a hard gelatine capsule dosage form containing loading (plain drug) as well as sustained fraction of drug in form of microcapsules. It was found that dosage form also showed good in vitro release profile.