FORMULATION AND EVALUATION OF GASTRO-RETENTIVE DRUG DELIVERY SYSTEM OF ATORVASTATIN CALCIUM

Atorvastain is a HMG-CoA reductase inhibitor used in the treatment of hyperlipidaemia. The absolute bioavailability of atorvastatin is approximately 14%. It also undergoes high first pass metabolism. Here, an attempt is made to formulate gastro-retentive non-effervescent floating tablets of atorvastatin to prolong the residence time of the dosage forms within the GIT. Atorvastatin showed wavelength maxima at 243 nm in 0.1 N HCL + 0.5% SLS. Various formulations were developed by using release rate controlling HPMC K4M, HPMC E5LV and POLYOX 303 in combinations by direct compression method. The prepared tablets were characteristics by good hardness, weight variation, friability, lag time, total floating time, in vitro drug release using USP dissolution test apparatus Type ? II (paddle method) in dissolution medium of 0.1 N HCl + 0.5% SLS. Drug-polymer compatibility studies by FTIR gave conformation about drug purity and showed no interaction between drug and selected polymers. From among all the developed formulations, as F2 prolonged the drug release (98.73±0.62 %) for longer period of time (24 hrs.); The lag time of optimized formulation (F2) was upto 116 sec. they were selected as optimized formulations. The optimized formulations were found to be stable during stability studies for one month.