Formulation development and evaluation of bilayer push-pull osmotic pump tablet of Ramipril

Abstract

The aim of the present work was to design and evaluate Push-Pull Osmotically Controlled Drug Delivery

system of Ramipril. Push pull osmotic tablets are bilayered tablets consisting of pull layer (drug layer)

and push layer (polymer layer) coated with semi permeable membrane containing water leaching pore

forming agents. Ramipril is an oral antihypertensive agent which belongs to BCS class II drug with half life

of 2-4 hours. Main objective to formulate this system was to achieve zero order release. The present study

was also aimed to develop a system that would reduce the frequency of dosing and thus increases

patient compliance. In this study an attempt was made to design formulations with varying

concentration of polymers. Opadry CA was used as film forming polymer. Mannitol was used as osmotic

agents. This system was developed in two stages: (a) Formulation of core tablet & (b) coating of tablet

core. Core tablets were evaluated for content uniformity, hardness, & weight variation while coated tablets

were evaluated for film thickness and In Vitro release study. All the post compression and precompression

parameters showed within limits. The drug- polymer interaction was also studied by conducting FTIR.

Selected formulation F1 having Polyox N-80 52% successfully 0.977. The KorsmeyerPeppas equation

showed the R 2 value to be 0.928 and‟ n‟ retarded drug release for 24hrs and drug release follows Zero

order kinetic with R

2

value of value was 0.596 following Zero Order & Anomalous (NonFickian

Diffusion). The stability studies were carried out at 40o C/75%RH for 90 days. There was no significant

change in the physical property during the stability period.