until completely dissolved the solution was allowed to cool to 18 u00b0 c maintaining stirring for a further three hours after precipitation the suspension was left for a further 2 hours with stirring at a temperature of 8 u00b0 c then filtered the product on the filter was washed with 20 ml of cold absolute ethanol and the wet solid dried under vacuum at 60 u00b0 c for 18 hours until a kf value less than 4 was attained the pxrd and ir spectra of the obtained product are shown in fig1 b and 2 b respectively the dissolution profile of the substance in amorphous form was also determined and compared with that of the substance in crystalline form it was found that the amorphous form easily dissolves in ethanol even without stirring while the crystalline form is less wettable moreover with regard to water solubility after conditioning a dissolution tester pharma test type ptw s iii s n 5390 using distilled water at a temperature of 37 u00b0 c u00b1 0 5 u00b0 c at a speed of 100 rpm four dissolutions were carried out in each of which the first three vessels of the dissolution tester were used for the substance in crystalline form and the last three for the substance in amorphous form 10 ml of the solute were withdrawn from each vessel after 15 minutes of stirring the withdrawn samples were filtered with 0 45 u03bcm filters and subjected to spectophotometric analysis repeating the operation after 30 and 60 minutes after one hour of dissolution the substance in crystalline form has a concentration of dissolved substance equal to about 7 of that of the substance in amorphous form consequently the substance in.