Lehr G J
U.S. Food and Drug Administration, Northeast Regional Laboratory, Brooklyn, NY 11232, USA.
J AOAC Int. 1996 Nov-Dec;79(6):1288-93.
An isocratic, reversed-phase liquid chromatographic (LC) method was developed for simultaneous determination of diphenoxylate hydrochloride (I) and atropine sulfate (II) in pharmaceutical products. Analysis is conducted on a Spherisorb CN column (5 microns), with a mobile phase consisting of 47% 0.001M pentanesulfonic acid sodium salt monohydrate, 53% acetonitrile, and 0.1% phosphoric acid. The detection wavelength is 220 nm. Tablets are extracted with acetonitrile-water (50 + 50). Oral solutions are determined directly after dilution. The method is validated for linearity, precision, system reproducibility, and accuracy. Recoveries at 80-120% of label claim ranged from 98.7 to 101.0% and from 99.6 to 102.5% for I and II, respectively. Results were linear (r > 0.9999) in the ranges 125-375 micrograms/mL and 1.25-3.75 micrograms/mL for I and II, respectively. Assay and content uniformity results for each ingredient, in both innovator products and generic formulations, are reported. Diphenoxylic acid, the principle degradation product and major metabolite of I, is separated and can be determined in tablets and oral solutions.
建立了一种等度反相液相色谱（LC）法，用于同时测定药品中盐酸地芬诺酯（I）和硫酸阿托品（II）的含量。分析在Spherisorb CN柱（5微米）上进行，流动相由47%的0.001M一水合戊烷磺酸钠、53%的乙腈和0.1%的磷酸组成。检测波长为220nm。片剂用乙腈-水（50 + 50）提取。口服溶液稀释后直接测定。该方法在线性、精密度、系统重现性和准确性方面得到了验证。对于I和II，标签标示量80 - 120%时的回收率分别为98.7%至101.0%和99.6%至102.5%。I和II的结果在125 - 375微克/毫升和1.25 - 3.75微克/毫升范围内呈线性（r > 0.9999）。报告了创新产品和仿制药制剂中各成分的含量测定和含量均匀度结果。I的主要降解产物和主要代谢物二苯氧基酸可在片剂和口服溶液中分离并测定。
