Abstract:

Objective To develop the method of high performance liquid chromatography (HPLC) for detection of contents of (S)-OTS and its hydrolysis products (1R,3S,5R,6S)-6-hydroxy-3-paramethylphenylsulfonyloxy tropane (HTT) and paratoluenesulfonic acid (TsOH), and evaluate the stability of antiglaucoma new drug (S)-OTS·HCl in solution. Methods Chromatographic conditions for HPLC: chromatographic column, Diamonsil-C18; mobile phase, methanol-10 mmol/L sodium dihydrogen phosphate (containing 5 mmol/L tetrabutylammonium bromide) (53∶47); flow rate, 1.0 mL/min; detection wavelength of violet, 227 nm; column oven temperature, 31 ℃; sample volume, 10 μL. Verification of the established HPLC method was performed. With 0.03% (S)-OTS·HCl in solution as samples, the established HPLC method was employed to detect the content of solute for stability evaluation. Results Specific tests indicated that HTT and TsOH were well resolved from each other and from (S)-OTS. Linear correlation test demonstrated that (S)-OTS, HTT and TsOH had linear correlation with chromatographic peak areas in the scope of standard concentration of serial controls [(S)-OTS·HCl 6.066-606.600 μg/mL，HTT 5.304-530.400 μg/mL，TsOH 3.034-303.400 μg/mL] (r²>0.999). The method conditions were fully validated with acceptable sensitivity (limit of detection and limit of quantitation), precision, stability and recovery rate. The tested samples hydrolyzed rapidly under room temperature, and the decrease of content of its main component (S)-OTS was in line with the increase of content of its hydrolysis product TsOH. Conclusion The method of HPLC for quantitative analysis of main component (S)-OTS and its hydrolysis products HTT and TsOH is established. The stability of (S)-OTS·HCl in solution for medical purpose is influenced by temperature, and its hydrolysis usually takes place in sulfonate site.

Key words: (S)-OTS·HCl, hydrolysis products, stability, high performance liquid chromatography