Evaluation of solid-state forms present in tablets by Raman spectroscopy

In this study the potential of Fourier transform (FT)-Raman spectroscopy as a method to probe the solid-state form of active substances present in tab lets and capsules is explored. Raman spectra were obtained from intact tabl ets and capsules containing enalapril maleate, prednisolone, form I and for m II polymorphs of ranitidine, anhydrous and monohydrate theophylline, and warfarin sodium clathrate. Spectra were also collected from the correspondi ng drug substances. These studies show that it is possible to detect the ac tive ingredients in the intact dosage form, even where the substance compri ses <1% of the total mass of the tablet. Moreover, it is shown that, in som e cases, Raman spectroscopy can also be used to investigate the solid-state form of a drug present in the dosage form and even to determine if a mixtu re of forms are present. (C) 2000 Wiley-Liss, Inc. and the American Pharmac eutical Association.