Determination of polymorphic forms of ranitidine-HCl by DRIFTS and XRPD

The identification. characterization and quantification of crystal forms ar e becoming increasingly important within the pharmaceutical industry. A com bination of different physical analytical techniques is usually necessary f or this task. In this work solid-state techniques, diffuse reflectance infr ared Fourier transform spectroscopy (DRIFTS) and X-ray powder diffractometr y (XRPD) were combined to analyze polymorphic purity of crystalline ranitid ine-HCl. an antiulcer drug, H2 receptor antagonists. A series of 12 differe nt mixtures of Form 1 and 2 was prepared by geometric mixing and their DRIF T spectra and XRD powder patterns were obtained and analyzed, either alone or combined together, using Artificial Neural Networks (ANNs). A standard f eed-forward network. with back-propagation rule and with multi layer precep tron architecture (MPL) was chosen. A working range of 1.0-100%: (w/w) of c rystal Form 2 in Form 1 was established with a minimum quantifiable level ( MQL) of 5.2% and limit of detection of 1.5% (w/w). The results demonstrate that DRIFTS combined with XRPD may be successfully used to distinguish betw een the ranitidine HCl polymorphs and to quantify the composition of binary mixtures of the two. (C) 2001 Elsevier Science B.V. All rights reserved.