A powder X-ray diffraction technique has been developed for the quantitative analysis of the active ingredient in intact tablets. Carbamazepine (CBZ) was the model drug and the other tablet ingredients were microcrystalline cellulose, starch, stearic acid and silicon dioxide. The integrated intensities of 21 X-ray lines of CBZ were used for the quantitative analysis. The ratio of the intensities of the X-ray lines in these tablets to the intensity of the same lines in tablets containing only CBZ was calculated as a function of the CBZ weight fraction. Such a calculation was based on the mass absorption coefficients of the tablet ingredients. These ratios were also experimentally determined in prepared tablets wherein the weight fraction of CBZ ranged from 0.51 to 0.69. There was a good agreement between the calculated and experimental intensity ratios. The relative error in the determination of CBZ was less than 10%. Small changes either in the compression pressure or in the tablet composition did not affect the validity of the assay method.
- Multi-component tablet
- Quantitative powder X-ray diffractometry