Solubility of 7-chloro-2-methylamino-5-phenyl-3H-1,4-benzodiazepine-4- oxide,7-chloro-1,3-dihydro-1-methyl-5-phenyl-2H-1,4-benzodiazepin-2-one, and 7-chloro-5-(2-chlorophenyl)-3-hydroxy-1,3-dihydro-1,4-benzodiazepin-2-one in (propane-1,2-diol + water) at a temperature of 303.2 K

Experimental solubilities of 7-chloro-2-methylamino-5-phenyl-3H-1,4- benzodiazepine-4-oxide (chlordiazepoxide), 7-chloro-1,3-dihydro-1-methyl-5- phenyl-2H-1,4-benzodiazepin-2-one (diazepam), and 7-chloro- 5-(2-chlorophenyl)- 3-hydroxy-1,3-dihydro-1,4-benzodiazepin-2-one (lorazepam) in (propane-1,2-diol + water) at T = 303.2 K were reported. The solubility of drugs increased with the addition of propane-1,2-diol and reached the maximum values in pure propane-1,2-diol. The Jouyban-Acree model was used to fit the experimental data, and the solubilities were reproduced using a previously trained version of the Jouyban-Acree model and the solubility data in monosolvents in which the overall mean relative deviations (OMRDs) of the back-calculated and predicted values with the corresponding experimental data were 4.2% and 10.7%. The solubilities of the three drugs were also predicted using a trained version of the log-linear model of Yalkowsky, and the OMRD was 21.1%. © 2010 American Chemical Society.