DIRECT ASSAY AND SHELF-LIFE MONITORING OF ASPIRIN TABLETS USING RAMAN-SPECTROSCOPY

A comparison was made between Raman and high-performance liquid chroma tography (HPLC) analysis of aspirin tablets. The basis was an assay of aspirin content and the determination of salicylic acid produced by d ecomposition. Raman observations were performed directly on both intac t 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 Ra man measurement is somewhat better than that of the HPLC measurement. Both methods were used in a degradation study in which samples were st ored 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. (C) 1997 Elsevier Science B.V.