In vivo evaluation of nitrofurantoin floating solid drug delivery system

The aim of the present study was to describe the in vivo performance and pharmacokinetic parameters of formulated floating tablets and capsules containing nitrofurantoin, different grades of hydroxypropyl methylcellulose (HPMC) and a gas generating agent. The bioavailability study was performed on six human volunteers using HPLC analysis of urine samples and was compared with non-floating commercial capsules of the drug. The results showed that the floating formulations were capable of maintaining therapeutic urinary levels up to 12 h with a higher extent of recovered unchanged drug (45.46-56.45 mg). The relative bioavailability of floating formulations calculated from the total area under the urinary excretion rate-time curve (AUC0 -24) was found to be increased about 1.66-2.06 times in comparison to the marketed capsules. In vitro-in vivo correlation was done by relating the cumulative percent dissolved to the cumulative percent excreted in urine and a good linear correlation was found. None of the human volunteers who administered the floating formulations exhibited any adverse effects characterized by the pure nitrofurantoin.