Solubilities of testosterone propionate and related esters in organic solvents

The solubility parameters of a range of saturated hydrocarbons were calculated from vapor pressures and heats of vaporization. Solubilities of testosterone propionate were determined in these solvents at 25 degrees and yielded solute solubility parameters which varied from solvent to solvent. The solubility parameter of testosterone propionate was determined by several other methods, and support was found for the previously published figure of 9.5 cal(1/2) cm(-3/2). The geometric mean coefficient (l(12)) in saturated hydrocarbons was found to be a rectilinear function of the branching ratio (r). The mean l(12) of androstanolone and testosterone propionates was used to calculate the solubilities of other esters, giving good agreement with experimental results. IR data, presented as the sum of the shifts of the 3-keto and 17-ester carbonyl stretching frequencies in polar solvents, correlated rectilinearly with the geometric mean coefficients and the plot extrapolated to the l(12) value of n-hexane, calculated from the branching ratio plot. Attempts to predict solubilities of other esters in polar solvents using l(12) values achieved only limited success.