Enhanced dissolution of furosemide by coprecipitating or cogrinding with crospovidone

To increase the dissolution rate of furosemide, cogrinding or coprecipitating of furosemide with crospovidone was carried out. The 1:2 (w/w) ground mixture of furosemide with crospovidone was prepared by cogrinding in a ceramic ball mill and the coprecipitate was prepared by the solvent method using methanol. The dissolution test was carried at 37 +/- 0.5 degrees C and 150 rpm in simulated gastric fluids (pH 1.2). The dissolution rate of furosemide was rapid and markedly enhanced by cogrinding or coprecipitating with crospovidone. The X-ray diffraction, IR, DTA and TGA studies showed the physicochemical modifications of the furosemide from the ground mixture or the coprecipitate. Furosemide alone or furosemide contained within a physical mixture was crystalline in nature, whereas furosemide in the ground mixture or the coprecipitate was not crystalline even when preserved at room temperature for 1 year. An interaction, in the ground mixture or in the coprecipitate, such as an association between the functional groups of furosemide and crospovidone may have occurred at the molecular level, changed the thermal property and increased the dissolution of furosemide. The cogrinding or coprecipitating techniques with crospovidone provide a promising way to increase the dissolution rate of poorly soluble drugs. (C) 1998 Elsevier Science B.V. All rights reserved.