Simultaneous Determination of Two Stabilizers Content in Lutetium[177Lu] Oxodotreotide Injection by High-Performance Liquid Chromatography

A high-performance liquid chromatography(HPLC) was established for the determination of stabilizer(gentisic acid, vitamin C) content in lutetium[177Lu] oxodotreotide injection. The liquid chromatographic parameters were finally confirmed by the optimization experiments of the chromatographic column, mobile phase, elution gradient and UV wavelength. The chromatographic column(4.6 mm×250 mm×5 μm) filled with octadecylsilane bonded organic hybrid silica gel was used, and the mobile phase was 0.82 g/L sodium acetate solution(pH was adjusted to 3.50 with glacial acetic acid) and methanol(gradient elution). The detector system was ultra-violet visible spectroscopic detector(detection wavelength was 295 nm) and radioactive flow detector connnected in series. The column temperature was 25 ℃, the injection volume was 5 μL, the running time was 20.0 min, and the flow rate was 1.00 mL/min with gradient elution. The method can effectively separate gentisic acid and vitamin C, and the resolution meets the requirement of greater than 1.5. The linear ranges of gentisic acid and vitamin C are 0-1.50 g/L and 0-30.0 g/L, respectively. The correlation coefficient r are 1.000 and 0.998, respectively. When the chromatographic conditions of column temperature, flow rate and mobile phase pH are changed, the relative standard deviation(sr) of vitamin C and gentisic acid in the sample solution are 1.62% and 1.16%(n=9) respectively, meet the requirement of less than 2.0%. The sr of the retention and content of gentisic acid in six samples are 0.10% and 0.13%, respectively. The sr of the retention and content of vitamin C in six samples are 0.06% and 0.19%, respectively. The sr of the retention and content of gentisic acid in twelve samples are 0.18% and 0.30%, respectively. The sr of the retention and content of vitamin C in twelve samples are 0.10% and 1.49%, respectively. The above sr results all meet the requirement of less than 2.0%. The rate of recovery of gentisic acid meets the requirement of 90%-108%, and the rate of recovery of vitamin C meets the requirement of 92%-105%. This method can accurately determine the contents of gentianic acid and vitamin C without diluting the sample, improving measurement accuracy and reducing radiation dose. The method has good durability, accuracy, and precision. The HPLC method is simple, rapid, sensitive, and accurate, which can be used for the accurate determination of gentisic acid and vitamin C in lutetium[177Lu] oxodotreotide injection, and provide guidance for the optimization of the process of these drugs.