Simultaneous Determination of Co-formulated Matrine and Secnidazole in Suppositories by Reverse Phase High Performance Liquid Chromatography

Purpose: To develop and validate a new, simple, sensitive and accurate high performance liquid chromatographic (HPLC) method for the simulataneous determination of matrine and secnidazole in suppositories. Methods: The method involved using a SinoChoom ODS-BP C18 column (5 μm, 4.6 mm × 200 mm) and mobile phase consisting of acetonitrile–triethylamine (0.05 %) in 0.025 mol/L KH2PO4 (20:80, v/v). The flow rate was 1 mL/min and detection was monitored at 210 and 311 nm for matrine and secnidazole, respectively. Total run time was 10 min and the column was maintained at 35 °C. Results: The excipients in the suppository did not interfere with the drug peaks. Matrine was eluted at a retention time (RT) of 4.30 min while linearity for the quantification of drug was obtained in the concentration range of 10.0 - 100.0 μg/mL (r^2 = 0.9991). Secnidazole was eluted at a retention time (tr) of 6.69 min and linearity for the quantification of the drug was obtained in the concentration range of 10.0 - 150.0 μg/mL (r^2 = 0.9993). Intra- and inter-day variations were 1.0 % for both matrine and secnidazole. Conclusion: The developed HPLC method was validated according to International Conference on Harmonisation (ICH) guidelines and proved to be suitable for the simultaneous determination of matrine and secnidazole in suppositories.