Rapid Screening of Tenoxicam in Anti-Rheumatic Chinese Patent Drugs by IR in Combination with Discriminant Analysis

Thirty kinds of anti-rheumatic Chinese patent drugs sold on market were taken as testing samples, and 15 of which, proved to contain no tenoxicam, were selected as the negative samples. Portions of about 0.2 g were taken from each of the negative samples, and were extracted ultrasonically with 10 mL of methanol separately. After filtering, the solution of the 15 negative samples were thus obtained. Three portions (about 0.2 g each) of each of the 15 negative samples were taken and 10, 15, 20 mg of tenoxicam were added respectively. These samples were extracted each with 10 mL methanol as described for the negative samples. Thus the solution of 45 positive samples were obtained. About 0.2 g sample portion was then taken from each of the 30 testing samples and extracted with 10 mL of methanol as described for the negative samples. Thus the solution from the 30 testing samples were obtained. Aliquots of 5 μL were taken from each of the above described solution and their IR spectra were taken. By using the soft ware TQ Analyst 9.0 and based on the IR spectra, discriminant analysis was applied to obtain the model for rapid screening of tenoxicam admixed into the anti-rheumatic Chinese patent drugs. It was found that by using the established model, rate of correct recognition of 100% was attained, with misdeeming case of zero.