Formulation of Sustained Release Floating Microspheres of Furosemide from Ethylcellulose and Hydroxypropyl Methylcellulose Polymer Blends

Abstract

Furosemide is a potent and commonly used loop diuretic. It is absorbed largely in the stomach and upper small intestine. This narrow absorption window is responsible for its low bioavailability of about 50%, and variable and erratic absorption. The objective of the present investigation was to formulate and evaluate floating microspheres of furosemide for prolonged buoyancy with sustained delivery of the drug into the gastric content. Furosemide loaded microspheres were prepared by the solvent evaporation method. The drug entrapment efficiency was high for all of the formulations ranging from 86.2 to 98.4%. The yield of microspheres production was good partticularly at increased EC/HPMC ratio and lower temperatures. Drug amount and EC/HPMC ratio showed highly significant effects (p<0.0001) on cumulative drug release and buoyancy of microspheres. Floating microspheres that effectively sustain the drug release more than 12 h and exhibit buoyancy of greater than 77% in 12 h were developed. Finally the study confirmed that various furosemide loaded EC/HPMC microspheres formulations could be developed that effectively sustain the drug release for a desired period by varing the ratio of EC and HPMC, and drug amount.