采用分光光度法研究了法莫替丁和茜素红的荷移反应,建立了荷移分光光度法测定法莫替丁的方法.在水溶液中,法莫替丁和茜素红形成的络合物的最大吸收波长为525 nm,两者的组成比为1比1.法莫替丁质量浓度在8.0~142.0 mg·L-1范围内符合比耳定律.采用此方法分别测定了法莫替丁片剂和胶囊中法莫替丁含量,所得测定值与标示值相符.用标准加入法作方法的回收和精密度试验,测得回收率为100.8%(片剂)和99.6%(胶囊),测定值的相对标准偏差(n=7)依次为1.01%及0.56%.

As studied by photometry,a complex with composition ratio of 1 to 1 was formed by the charge-transfer reaction between famotidine and alizarin red,having its absorption maximum at the wavelength of 525 nm.Linear relationship between values of absorbance and mass concentration of farmotidine was obtained in the range from 8.0 to 142.0 mg·L-1.Based on these facts,a method of photometric determination of famotidine was proposed and used in the analysis of drug samples of famotidine tablets and capsules for their famotidine contents,giving results in consistency with the labelled values.Tests for recovery were performed by standard addition method using these drug samples as matrixes.Values of average recovery found were 100.8% for the tablets and 99.6% for the capsules.The RSD′s (n=7) calculated from the measured values were 1.01% and 0.56% respectively.