Formulation and Evaluation of Bilayer Tablets of Ramipril as Immediate Layer and Propranolol Hydrochloride as Sustained Layer

Abstract

Aim: The purpose of this research work was to develop a bilayer tablet of antihypertensive drugs having sustained
release (SR) layer of propranolol hydrochloride and immediate release (IR) layer of ramipril. Objectives: In the
present investigation, an attempt was made to reduce the frequency, units of dose administration, and to improve the
patient compliance. Materials and Methods: The tablets were prepared using ethyl cellulose and hydroxypropyl
methylcellulose K-15M for sustained layer of propranolol hydrochloride and superdisintegrants crospovidone and
sodium starch glycolate for IR layer of ramipril. Preformulation studies of propranolol hydrochloride and ramipril
like compatibility studies with polymers using Fourier-transform IR were carried out. The drugs and excipients
were found to be compatible with each other. Compressed tablets were evaluated for hardness, thickness, weight
variation, friability, drug content, in vitro drug release studies, and stability studies Results and Discussion: Nine
batches of bilayer tablets of propranolol hydrochloride and ramipril were developed using wet granulation and
direct compression techniques, respectively. Among the nine formulations, F9 batch showed best drug release
over 12 h and subjected to stability studies for 2 months. Conclusion: The optimized F9 formulation for IR
showed a release of 99.27% and propranolol hydrochloride has an in vitro release of 99.39%. Therefore, bilayer
ramipril IR and SR tablets of propranolol hydrochloride can be used to improve the management of hypertension