FORMULATION DESIGN AND IN VITRO EVALUATION OF EPLERENONE GASTRORETENTIVE FLOATING MATRIX TABLETS FOR THE MANAGEMENT OF HYPERTENSION

This study aimed to design and assess a hydrodynamically balanced floating matrix-controlled drug delivery system for Eplerenone. The elimination half-life of Eplerenone ranges from 3 to 6 hours. The gastric buoyancy of Eplerenone tablets is due to the effervescence generated by the reaction between sodium bicarbonate and hydrochloric acid in the stomach. Twelve distinct formulations of floating tablets were developed utilizing the direct compression method with hydrophilic polymers, including HPMC K4M, K15M, and K100M, alongside hydrophobic polymers such as Eudragit RSPO, in diverse ratios. The characterisation of the formulated preparation was conducted utilizing FTIR and DSC analyses. The evaluation results indicated that all formulations adhere to the specifications of official pharmacopoeias and/or standard references regarding general appearance, content consistency, hardness, friability, and buoyancy. Among all the formulations created, formulation EFT10, which comprises 25% HPMC K100M and 12.5% eudragit RSPO, demonstrated optimal in vitro drug release, achieving 99% at the conclusion of 12 hours. Formulations containing above 12.5% NaHCO3 exhibited a floating duration exceeding 12 hours. The kinetics of in vitro drug release for the improved formulation EFT10 exhibited zero-order kinetics, with a drug release mechanism characterized by anomalous diffusion combined with erosion. Accelerated stability experiments were conducted, revealing little alteration in physicochemical attributes and drug release profiles after 90 days, showing that all formulations remained stable. Key words: Gastroretensive drug delivery, floating drug delivery, Eplerenone, Eudragit RSPO, HPMC K4M, K15M, K100M