<scp>Effective solvent system selection</scp> in the <scp>recrystallization purification</scp> of <scp>pharmaceutical products</scp>
Richard J. Fickelscherer, Christian M. Ferger, Stephanie A. Morrissey
Abstract
Abstract This treatment describes the details of a methodical three step algorithm for determining the best operating conditions for the recrystallization separations of solid mixtures for the chosen targeted solvent systems. Our algorithm was applied to effectively separate a representative pharmaceutical product (caffeine) from a related pharmaceutical product (theophylline). The limitations of such calculations with currently available, widely used predictive methods for computing solution thermodynamics without experimental data are directly examined. Also presented here is a novel two stage recrystallization procedure which can potentially dramatically improve the overall recovery yields of the desired products. These systematic selection calculations described herein should enable researchers to quickly screen many potential solvent systems and operating conditions and concentrate experimental efforts only on the most promising candidates for such purifications.