Determination of Content and Related Substances of Methylthioninium Chloride Injection by HPLC / 中国药师

ABSTRACT

Objective:To establish an HPLC method for the determination of methylthioninium chloride injection and its related substances. Methods:Octadecylsilane bonded silica was used as the filler. A Waters Symmetry C18 column (150 mm × 4. 6 mm, 5μm) was used with the mobile phase of 0. 3% phosphoric acid solution-acetonitrile (70∶ 30). The detection wavelength was 246 nm and the column temperature was 30℃. The flow rate was 1. 0 ml·min-1 and the injection volume was 10μl. Results:The separation degree of methylthioninium chloride peak and impurity peaks was good. Methylthioninium chloride within the range of 2. 0-60. 0 μg· ml-1showed a good linear relationship (r=0. 9998). Impurity A within the range of 0. 2-3. 2 μg·ml-1 showed a good linear relation-ship (r=0. 999 6). The average recovery of methylthioninium chloride was 99. 75% and RSD was 0. 86% (n=9). Conclusion:The method is simple, accurate and specific with high precision. It can be used to determine the content of methylthioninium chloride injec-tion and its related substances.