Jitendra Kumar*, Pravin Gupta, Rahul Dev, Saurabh Kumar
Sir Madanlal Institute of Pharmacy Aalampur Hauz, Etawah-206001, U.P., India
Gastroretentive floating drug delivery systems (GFDDS) of atenolol, an antihypertensive drug, with an oral bioavailability of only 50% (because of its poor absorption from lower gastrointestinal tract) have been designed and optimized using 3² full factorial design. Hydroxypropyl methyl cellulose of different viscosity grades (K4M and 50 cps) were used as the polymers and sodium bicarbonate as gas generating agent to reduce floating lag time. The tablets were prepared by direct compression method. Estimation of atenolol in the prepared tablet formulations was carried out by extracting the drug with methanol and measuring the absorbance at 225.3 nm. The prepared formulations were further evaluated for hardness, friability, weight variation, drug content uniformity, swelling index, in vitro drug release pattern, short-term stability and drug excipient interactions. Majority of the designed formulations displayed nearly first order release kientics, releasing more than 80% drug in 10 hours and remained buoyan than 24 hours. The optimized formulation containing atenolol 50 mg, HPMC (50 cps) 100 mg and sodium bicarbonate 30 mg has displayed almost zero order release kinetics with a floating lag time of only 2.9 minutes. This formulation released more than 90% drug in 9 hours. This study proves that GFDDS of atenolol can be designed using HPMC 50 cps as matrix polymer, which provides nearly zero order release kinetics and thus possible enhancement of oral bioavailability of the drug.