Abstract: Objective To establish a method for the determination of polymers in desmopressin acetate using size exclusion chromatography. Methods A size exclusion chromatography method was employed, using a TSKgel G2000SWXL column (TSKgel G2000SWXL, 7.8 mm×300 mm, 5μm) with a mobile phase consisting of phosphoric acid-acetonitrile-methanol-water (0.2∶15∶5∶80) (with pH adjusted to 2.5 by disodium hydrigenphosphate buffer) at the flow rate of 0.3 mL·min^-1. The column temperature was 25℃, the detection wavelength 210 nm, and the injection volume was 50 µL. Results The peaks of the parallel-dimer and desmopressin acetate were well separated with a good specificity, durability and precision. The parallel-dimer, cross-dimer and desmopressin acetate showed a good linear relationship within the concentration ranges of 0.01-21.6 μg·mL^-1, 0.01-22.9 μg·mL^-1 and 0.01-25.6 μg·mL^-1, respectively (r>0.99). The limits of detection and quantification for the parallel-dimer, cross-dimer and desmopressin acetate were 0.14, 0.31, 0.17ng and 0.43, 0.46, 0.51 ng, respectively. The average recovery (n=9) of the parallel-dimer and cross-dimer ranged from 95% to 105%, indicating good accuracy. Conclusion This method is operable, accurate and sensitive, making it desirable for the determination of polymers in desmopressin acetate.

Key words: Desmopressin Acetate, Size Exclusion Chromatography, Polymers, Parallel-Dimers, Cross-Dimers