Abstract: 
Pregabalin has a short elimination half-life and is absorbed in the small intestine and the ascending colon in humans but is poorly absorbed beyond the hepatic flexure. The purpose of this study was to develop a gastro retentive effervescent controlled release drug delivery system with swelling and floating properties. Tablet formulations were designed using hydroxyl propylmethylcellulose (HPMC K15M) and sodium alginate (Na alginate) as release-retarding polymer(s) and sodium bicarbonate (NaHCO₃) as a gas former. Floating behavior, swelling study and drug release studies were performed in 0.1 N HCl (pH1.2) at 37 ± 0.5°C. The tablets showed acceptable physicochemical properties. Drug release profiles of all the 12 batches formulated followed zero order. Statistical analysis of data done by design expert software revealed that the desired physicochemical properties of effervescent matrix tablets could be achieved by optimization through 3² full factorial designs. The optimized batch was promising and exhibited excellent floating properties, swelling properties and sustained drug release characteristics. This optimized batch was stored at 40˚C /75% RH for 3 months according to ICH guidelines. It was concluded that combination of HPMC K15M, sodium alginate, and sodium bicarbonate showed good swelling, floating and drug release characteristics.

Keywords: Pregabalin, Gastric Emptying Time, Floating Matrix Tablets, Release-retarding Polymers, 3² Full Factorial Design.