Hanna G M, Lau-Cam C A
Food and Drug Administration, New York Regional Laboratory, Brooklyn 11232.
J Assoc Off Anal Chem. 1988 Nov-Dec;71(6):1118-21.
Based on the structural differences between quinidine and dihydroquinidine, a 1H-nuclear magnetic resonance spectroscopic method previously reported for quinidine drug substance was modified and shown to be applicable to the quantitative determination of both compounds in quinidine sulfate tablets. Deuterated chloroform was used as the solvent and hexamethylcyclotrisiloxane served as an internal standard. The average recovery and standard deviation of quinidine sulfate (calculated as the sum of quinidine sulfate plus dihydroquinidine sulfate) from synthetic formulations was 98.94 +/- 0.43% (n = 10). Five lots of 200 mg tablets of quinidine sulfate from one commercial source were found to contain from 92.9 to 95.8% quinidine sulfate, and from 1.1 to 7.0% dihydroquinidine sulfate.
基于奎尼丁和二氢奎尼丁之间的结构差异，对先前报道的用于奎尼丁原料药的1H核磁共振光谱法进行了改进，结果表明该方法适用于硫酸奎尼丁片中两种化合物的定量测定。以氘代氯仿为溶剂，六甲基环三硅氧烷为内标。合成制剂中硫酸奎尼丁（以硫酸奎尼丁与硫酸二氢奎尼丁之和计算）的平均回收率和标准差为98.94±0.43%（n = 10）。从一个商业来源获得的五批200 mg硫酸奎尼丁片剂中，硫酸奎尼丁含量为92.9%至95.8%，硫酸二氢奎尼丁含量为1.1%至7.0%。
