Preparation and characterization of furosemide nanosuspensions

Furosemide, a widely used loop diuretic, has a low aqueous solubility, and low permeability. Nanosuspensions have been widely used to increase the solubility of poorly soluble drugs. The aim of this study was to develop and characterize furosemide containing nanosuspensions. Furosemide nanosuspensions with Tween 80, were prepared using high pressure homogenization method using ultrasonic probe or ultra turrax, ball milling method, and combination of these methods. The physicochemical properties of furosemide, physical mixture and nanosuspensions were evaluated by FT-IR, DSC and X-ray analyses. Particle size, polydispersity index, zeta potential, solubility and permeability of nanosuspensions were also determined. FT-IR analysis revealed that characteristic peaks of furosemide were seen in all formulations. X-ray analysis indicated that crystalline structure of furosemide was preserved in nanosuspensions. The particle size of furosemide decreased significantly (p < 0.05) by using nanosuspension technology. Furosemide solubility was pH-dependent, and impact of nanosuspension on the solubility was more pronounced at lower pH values (e.g. pH 1.2). Furosemide permeability seemed to be influenced by nanosuspension preparation method. In conclusion, nanosuspension technology seems to be a promising approach for enhancement of solubility and permeability properties of poorly water soluble compounds, and it has an excellent potential to improve the bioavailability of such compounds.