Quantitative Evaluation of Drug Distribution in Tablets of Various Structures via Raman Mapping
Hyperspectral imaging was applied to provide quantitative spatial information about pharmaceutical samples. The aim was to characterize the distribution of active pharmaceutical ingredient (API) in manufactured samples quantitatively. Two kind of API, imipramine and spironolactone were applied in three conventional and two continuous processing technologies. The homogeneity of distributions of 10% API was determined through Raman maps applying macropixel analysis method. Non-overlapping macropixel analysis (Poole-index) and calculation of distributional homogeneity indices (DHIs) were compared as a measure of homogeneity. Non-overlapping macropixel approach proved to be more sensible than DHI evaluation. For enhancing efficacy of DHI we suggest a correction by weighting scores and considering relative standard deviations. This way the capability of DHI can be improved significantly. The very slight differences between the continuous methods (the homogeneity of which are much higher than that of conventional technologies) could be quantified.