FORMULATION AND IN-VITRO CHARACTERIZATION OF FLOATING TABLET OF ENALAPRIL MALEATE

The present study was aimed at developing an oral floating system for Enalapril maleate with the objective to enhance the oral bioavailability of the drug. As it is a prodrug, oxidizing agent KMnO₄ was used with distilled water and observed at 340 nm against a reagent blank, using PC Shimazdu UV Spectrophotometer. The obtained   standard graph of drug was a straight line with coefficient correlation (R ²) = 9.9984. 12 formulations were prepared in 2 batches using varying concentration of hydrophilic swelling polymer HPMC K15 M and effervescent agent i.e. NaHCO₃. Having a light sensitive drug all the experimental work had been done in the dark light room. Among the different formulation B₁F₆was considered as optimized formulation with a floating lag time of only 20 sec and floating time of more than 10 hour showed better floating behavior. It showed the release up to 60% of drug in 8 hr .The release of Enalapril maleate from all the formulations fitted to different release kinetic models, indicated that formulation B₁F₁ followed higuchi model and remaining all the formulation followed first order release kinetics. Among all, B₁F₆ showed maximum R²    value i.e. 0.9789 which insured uniform release profile as compared to other formulations. This result was encouraging, because a longer gastric residence time of tablet could certainly enhance the low oral bioavailability of the drugs by avoiding the incomplete absorption due to narrow absorption window.