Quantification of binary polymorphic mixtures of ranitidine hydrochloride using NIR spectroscopy

The propensity of molecules to form polymorphs increases with increasing functionality. Each polymorph is a separate patentable entity and may have different therapeutic properties. It is therefore important to develop methods for the identification and quantification of polymorphs alone and within active pharmaceutical ingredients. Various vibrational spectroscopic techniques have had promising results in the quantification of polymorphs in binary mixtures. Ranitidine hydrochloride exists as two polymorphs and has been used as a test compound in the assessment of various quantification techniques (e.g. X-ray powder diffraction, Raman spectroscopy, diffuse reflectance infra-red Fourier transform spectroscopy). This study investigates the accuracy of near-infrared spectroscopy when quantifying polymorphic binary mixtures of ranitidine hydrochloride. Ranitidine hydrochloride polymorphs may be identified and quantified from near-infrared spectra; however, not to the level of accuracy displayed by Raman spectroscopy.