酶催化分光光度法测定盐酸甲氧氯普胺

Enzymatic Spectrophotometric Determination of Metoclopramide Hydrochloride

试验发现血红蛋白（Hb）对酸性铬蓝K与过氧化氢的氧化褪色反应的催化作用因甲氧氯普胺的存在而受到抑制。此反应系在pH 9.5的氨性缓冲介质中进行,并根据在551 nm波长（为酸性铬蓝K在此条件下的吸收峰）处测得的吸光度A0（试剂空白溶液）、A1（加Hb溶液）及A2（加Hb和甲氧氯普胺溶液）,按所给公式计算反应的抑制率（I%）。甲氧氯普胺的浓度在3.0×10-6~1.2×10-4mol·L-1范围内与所算得的抑制率呈线性关系。上述反应的检出限（3s/k）为2.8×10-8mol·L-1。浓度水平在4.0×10-5mol·L-1时,测得其相对标准偏差（n=11）为4.6%。根据以上方法,测定了药物针剂中甲氧氯普胺含量,测得结果与其标示值相符。

It was found that the catalytic effect of hemoglobin（Hb） on the oxidation decoloration of acid chrome blue K by H2O2 in an ammoniacal buffer medium of pH 9.5 was inhibited by the drug ＂Metoclopramide＂.Rate of inhibition（I%） of Metoclopramide on the catalytic reaction was calculated from values of absorbance of reagent blank solution（A0）,absorbance of solution added with Hb（A1） and absorbance of solution added with Hb and Metoclopramide（A2）,measured at the wavelength of absorption maximum of acid chrome blue K（551 nm） by the given formula.Linear relationship between values of I% and concentration of Metoclopramide was obtained in the range of 3.0×10-6-1.2×10-4mol·L-1.Detection limit（3s/k） of the method was found to be 2.8×10-8mol·L-1.Precision was tested at the concentration level of 4.0×10-5mol·L-1,giving value of RSD（n=11） 4.6%.Based on these facts,the method was proposed to be used for analysis of injections of the drug for their contents of Metoclopramide giving results in consistency with the labelled values.