Formulation and evaluation of bi-layered floating tablets of Theophylline
N. Damodharan*, M. Mothilal, m.madhavi, P. Thejomayananthan
Bi-layered floating tablets of theophylline were developed using wet granulation technique. The current study aims at formulation and evaluation of bi-layered floating tablets of theophylline. The floating tablets of theophylline were formulated using polymers namely hydroxyl propyl methyl cellulose, sodium carboxy methyl cellulose, methyl cellulose and the tablets were evaluated. Two layered tablet formulations were designed with an immediately releasing layer consisting of theophylline with lactose as diluents and sustained release layer with slow releasing swellable matrix consisting of theophylline in hydroxyl propyl methyl cellulose, sodium carboxy methyl cellulose and methyl cellulose alone or in combination. The formulations were tested for drug release, floating time, floating lag time, drug content. Tablets formulated employing a combination of hydroxyl propyl methyl cellulose and methyl cellulose provide slow release of theophylline over a period of 9 hours and were found suitable for maintenance portion of bi-layered floating tablets. Theophylline release from these tablets was diffusion controlled and followed first order kinetics. The tablets exhibited good floating behavior in the stomach for 9 hours.
Key Words : Floating drug delivery system, theophylline, bi-layered, Hydroxy propyl methyl cellulose, Methyl cellulose
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