KINETIC-STUDY OF THE SOLID-STATE THERMAL INTERCONVERSION OF THE POLYMORPHIC FORMS OF CHLORAMPHENICOL PALMITATE

Kinetic studies revealed that the solid-state thermal interconversion of polymorphic forms of chloramphenicol palmitate at different tempera tures followed apparent zero-order kinetics. The transformation betwee n the metastable forms C and B was faster than the subsequent transfor mation of form B to form A. However, starting with form B the transfor mation to form A was slower than the transformation of form B, formed by the transformation of form C, to form A. The rate constant (k0) plo tted versus temperature (K) according to the Arrhenius equation was li near. There were significant differences in the activation energy and other thermodynamic parameters.