Spatial distribution and content detection of gefitinib in tablets using confocal micro-raman spectroscopy mapping

Abstract

In this study, we aim at establishing a method to evaluate the spatial distribution and content of gefitinib in tablets without destroying the tablets. The content of gefitinib tablets was determined by HPLC. Using confocal micro-Raman spectroscopy, with a wavelength of 785 nm and power of 10%, gefitinib, starch, and hydrated magnesium silicate were scanned. Tablets with five concentrations of gefitinib (15.63–31.25%) were scanned with a 1000 × 1000 μm spectral resolution and live video imaging was performed. The surfaces of gefitinib tablets were scanned and images were obtained by a continuous scanning method. Characteristic Raman spectra of tablets were obtained after surface scanning and map reviews of tablets with five concentrations of gefitinib for rapid and accurate identification. The characteristic spectral bands of gefitinib, starch, and hydrated magnesium silicate were 1620 cm–1, 480 cm–1, 1350 cm–1 respectively. Comparing the surfaces of the tablets, it was found that the tablets with a flat and round surface are more suitable for Raman spectroscopy. Live video imaging and scanning maps of five concentrations of gefitinib were performed. The results showed that the product with the content of 16.12% had a good mixing homogeneity. In conclusion, confocal micro-Raman spectroscopy can detect the spatial distribution and content of gefitinib tablets without destroying tablets.