Experimental solubility data for prednisolone and hydrocortisone in various solvents between (293.2 and 328.2) K by employing combined DTA/TGA

Solubility measurements were performed for the systems (11β)-11,17,21-trihydroxypregna-1,4-diene-3,20-dione (prednisolone) and (11β)-11,17,21-trihydroxypregn-4-ene-3,20-dione (hydrocortisone) in 10 solvents at atmospheric pressure within the temperature range, T = (293.2 to 328.2) K by employing combined digital thermal analysis and thermal gravimetric analysis (DTA/TGA) to determine liquid phase compositions at saturation. The maximum solubility for prednisolone and hydrocortisone was in N,N dimethylformamide at 328.2 K with x1 = 0.0141 and x1 = 0.0142 respectively. The lowest solubility was found to be prednisolone and hydrocortisone in water at 293.2 K with x1 = 0.0000105 and x1 = 0.0000115 respectively. The composition data was modelled using the Tsuboka-Katayma modified Wilson and NRTL activity coefficient models. There is satisfactory agreement between the experimental results and the models chosen. Furthermore, melting points and enthalpies of fusion of prednisolone and hydrocortisone were determined by combined DTA/TGA. The enthalpy of fusion and melting point of prednisolone and hydrocortisone was found to be 36,145 J·mol− 1 and 514.5 K and 33,900 J·mol− 1 and 486.1 K respectively.