INTERACTIONS BETWEEN PHARMACEUTICAL COMPOUNDS BY THERMAL METHODS

A critical evaluation of the utility of thermal methods for the detection of possible interactions occurring between solid components of pharmaceuticals is given. Differential thermal analysis (DTA), the cooling curve method, and the thaw‐melt method are used to obtain data from which phase diagrams are constructed for a number of binary systems. DTA is shown to be a versatile technique, demonstrating several advantages over the more classical methods of thermal analysis. Systems in which interactions were detected and stoichiometries determined include deoxycholic acid‐menadione (2:1), quinine‐phenobarbital (1:1), theophylline‐phenobarbital (2:1), caffeine‐phenobarbital (1:1), and atropine‐phenobarbital (1:1). Systems in which no interactions were detected include aspirin‐phenobarbital, phenacetin‐phenobarbital, diphenylhydantoin‐phenobarbital, and acetaminophen‐phenobarbital. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company