SOLUTION THERMODYNAMICS OF SOME POTENTIALLY LONG-ACTING NORETHINDRONE DERIVATIVES .1. VARIATION OF ENTHALPIES AND ENTROPIES OF FUSION WITH TEMPERATURE

Differential scanning calorimetry was used to determine the thermodynamic parametsrs of fusion of a number of potentially long-acting derivatives of the progestational steroid norethindrone from 260°K to their melting points. The differences in molar heat capacities of the crystals and supercooled liquid states were measured, and the enthalpies and entropies of fusion were shown to increase significantly with temperature. Entropies of fusion were correlated with the molecular structures of the derivatives. The value of such data in preliminary investigations of the physicochemical properties of new compounds is discussed. © 1979.