Fast determination of the release degree of compound sulfamethoxazole tablets by using circulation release system combined with ultraviolet spectral net analyte signal method.

Based on ultraviolet spectral net analyte signals, this research has studied the determination of the two effective components, sulfamethoxazole (SMZ) and trimethoprim (TMP), contained in compound sulfamethoxazole tablets in acid environment. The linear ranges of SMZ and TMP were 0.48-7.84 microg/ml (the regression correlation coefficient r = 0.9981) and 0.12-1.5 microg/ml (r = 0.9986), the corresponding average recoveries were 99.5 and 101.0%, respectively, and the relative standard deviations were 1.87 and 3.60%, respectively. The method was simple, fast and accurate. A circulation release system for the determination of the tablet release degree has been built, and the on-line filtering and small-volume sampling could thus be carried out. Thanks to the combination of the circulation release system and the determination method of SMZ and TMP in acid environment, the determination of release degree for compound sulfamethoxazole tablets was fast and accurate, especially for the early time of rapid release.