Purpose: To develop a gastroretentive formulation of bupropion hydrochloride in the form of floating tablets.

Methods: Floating tablets were prepared by wet granulation method using various amounts of sodium carboxymethycellulose (NaCMC), different molecular weight grade of hydroxypropyl methylcellulose (HPMC) and varying amounts of fillers (microcrystalline cellulose, lactose and tricalcium phosphate). Sodium bicarbonate was also incorporated as the gas-generating agent. The formulations were tested for their physical properties, floating lag time, duration of floating and in-vitro drug release.

Results: All the tablet formulations containing either HPMC K4M or HPMC K15M as the sustained-release polymer together with either microcrystalline cellulose (MCC) or lactose, floated in the release medium for > 10 h. Tablets prepared with MCC released ≥ 79 % of the drug after 10 h, while those prepared with lactose released ≥ 85 % of the drug within the same period. Tablets containing NaCMC alone did not show good floating properties but when HPMC K4M was also incorporated at certain ratios, tablets with good floating behavior and suitable drug release patterns were produced. Drug release kinetic studies showed that formulations fitted best to the Higuchi model.

Conclusion: The developed floating tablets of bupropion HCl exhibited prolonged drug release for ≥ 10 h, and, thus may improve bioavailability and minimize fluctuations in plasma drug concentration.