FORMULATION AND COMPARATIVE BIOAVAILABILITY OF CONVENTIONAL AND SUSTAINED-RELEASE FUROSEMIDE TABLETS

The release of furosemide incorporated into hydroxypropylmethyl cellul ose (HPMC) matrix tablets and conventional tablets was studied in vitr o using different dissolution media. The data obtained from in vitro t ests showed that the formulation containing 20% HPMC yields good susta ined release matrix tablets. The pH 6.6 dissolution medium (compared t o pH 4.6, 5.8 and 7.2) appears to be an appropriate test medium for as suring the difference among dosage forms for predicting in vivo bioava ilability. The formulated sustained release tablet of 40 mg furosemide was investigated for its bioavailability properties in comparison wit h conventional tablets containing 40 mg furosemide (Lasikal) in six he althy subjects. Compared to the conventional tablets, the sustained re lease tablets exhibited lower peak furosemide concentrations, longer t (max) values, and reduced bioavailability (77%). No significant advers e effect was experienced with any of the preparations.