PVP solid dispersions for the controlled release of furosemide from a floating multiple-unit system

The poor bioavailability of orally dosed furosemide (FUR) is due to the pre sence of a biological window, In the upper gastrointestinal tract. The purp ose of the present study was to develop and optimize in vitro a multiple-un it floating system with increased gastric residence time for FUR. The incom plete release of FUR from the units, related to its low water solubility, l ed to the preparation and evaluation of different FUR samples to be incorpo rated into the units. The complete dose release over the actual intragastri c residence time of the system (about 8 hr) was achieved by loading both th e core and the membrane forming the units with a 1:5 FUR/ polyvinylpyrrolid one (FUR/PVP) solid dispersion. Physicochemical analyses suggested the pred ominant role of the amorphous state of FUR in producing enhanced drug solub ility, and dissolution rate, which led to the desired release profile from the floating units.