In the present study, gastroretentive floating tablets of levofl oxacin hemihydrate were designed with objective of retention of tablet in acidic pH to improve bioavailability with reduction in dosing frequency. Hydroxypropyl methyl cellulose of different viscosity grades (K4M and K100LV) was used as polymer and sodium bicarbonate as gas generating agent to reduce floating lag time. Tablets were prepared by direct compression method. The prepared formulations were evaluated for hardness, friability, weight variation, drug content, swelling index, in-vitro drug release, short-term stability, floating lag time and in-vitro buoyancy. A 32 factorial design was applied to systematically optimize the drug release profi le. The proportions of release retardant material HPMC K100LV(X1), sodium bicarbonate (X2) were selected as independent variables and t50% (Y1), and t70% (Y2) were selected as dependent variables. The promising formulation containing levofl oxacin hemihydrate (100 mg), HPMC K100LV (100 mg) and sodium bicarbonate (80 mg) has t50% (5.95 h), t70% (8.52 h), floating lag time was only 10.33 sec and released more than 90% drug in 12 h. This study proved that gastroretentive drug delivery system of levofl oxacin hemihydrate was designed using HPMC K100LV, which provided excellent gastroretentive property, thus improved the bioavailability of drug.
Key words: Levofloxacin hemihydrate, Gastroretentive fl oating drug delivery systems, Hydroxypropyl methyl cellulose, 3² factorial design