Design and Characterization of a Gastro-Retentive Floating Atorvastatin Calcium Tablet

This study focuses on the formulation and evaluation of gastro-retentive floating tablets (GRFT) of atorvastatin calcium, aimed at improving its bioavailability and therapeutic efficacy. Atorvastatin calcium is a lipid-lowering agent with poor bioavailability due to extensive first-pass metabolism and a short half-life. Floating tablets were prepared using hydrophilic polymers, including HPMC K15M and xanthan gum, along with gas-generating agents such as sodium bicarbonate and citric acid, employing a direct compression method. The formulations were evaluated for physical parameters, in vitro buoyancy, swelling behavior, and drug release kinetics. Among the formulations, F5 exhibited the best performance, with a floating lag time of 10.58 seconds and a total floating time of up to 24 hours. Drug release studies revealed a sustained release of 99.70% over 12 hours for F5, attributed to an optimized balance of HPMC K15M and xanthan gum. Swelling studies demonstrated the highest swelling index (89.75% at 360 minutes) for F5, highlighting its enhanced hydration and gel formation properties. The drug release kinetics showed an inverse relationship between polymer concentration and drug release rate, indicating that higher polymer concentrations result in slower release due to a denser gel matrix. All formulations met pharmacopoeial standards for hardness, friability, weight variation, and content uniformity. The optimized formulation F5 successfully enhanced gastric retention and controlled drug release, making it a promising system for improving atorvastatin bioavailability and patient compliance. This approach can also be applied to other drugs with absorption windows in the upper gastrointestinal tract.