Polyamide layer chromatography of some antipyretics

Direct assay and shelf-life monitoring of aspirin tablets using Raman spectroscopy

A comparison was made between Raman and high-performance liquid chromatography (HPLC) analysis of aspirin tablets. The basis was an assay of aspirin content and the determination of salicylic acid produced by decomposition. Raman observations were performed directly on both intact and powdered tablet material. The limit of detection of HPLC with an ultraviolet detector is lower than that of the Raman measurement, but both are adequate for this application. The reproducibility of the Raman measurement is somewhat better than that of the HPLC measurement. Both methods were used in a degradation study in which samples were stored in a humid atmosphere for a maximum period of 8 weeks. Aside from somewhat higher salicylic acid responses from the HPLC method, which were attributed to hydrolysis during chromatography, results from the two methods were comparable. Direct Raman measurements are faster and do not require the use of solvents.

Comparison of assay methods by second-derivative spectroscopy, colorimetry and fluorescence spectroscopy of salicylic acid in aspirin preparations with a high-performance liquid chromatographic method

Second-derivative spectroscopy, colorimetry and fluorescence spectroscopy have been compared with a high-performance liquid chromatographic (HPLC) method for the assay of salicylic acid in preparations of aspirin. Results are presented for the linearity, sensitivity and reproducibility of these methods. The second-derivative spectroscopic and the HPLC methods were acceptable in terms of linearity, sensitivity and inter-day reproducibility and were convenient for the routine analysis of salicylic acid in aspirin preparations.