分光光度法测定琥乙红霉素的含量

Determination of Erythromycin Ethylsuccinate Content by Spectrophotometry

甲基绿与琥乙红霉素于50℃在pH值7.8的NaH_2PO_4-Na_2HPO_4缓冲溶液中反应30min,可形成稳定的络合物;琥乙红霉素在550~670nm几乎无吸收,而甲基绿有明显吸收,甲基绿与琥乙红霉素形成的络合物在633nm附近吸光度明显降低。基于此建立了测定琥乙红霉素含量的分光光度法。琥乙红霉素浓度在0.9~150μg·mL^(-1)范围内服从比尔定律,相关系数为0.9998,方法的检出限为0.19μg·mL^(-1),络合物的表观摩尔吸光系数ε为4.77×10^(4 )L·mol^(-1)·cm^(-1)。利用本法测定琥乙红霉素片中琥乙红霉素的含量时,加标回收率在98.6%~105.3%之间,相对标准偏差(n=5)为2.2%。

Methyl green can react with erythromycin ethylsuccinate to form complex under 50℃in the sodium dihydrogen phosphate-disodium hydrogen phosphate buffer solution with pH value of 7.8for 30min.Erythromycin ethylsuccinate shows weak absorbance at 550~670nm,while methyl green shows obvious absorption peak.The absorbance of the complex formed with methyl green and erythromycin ethylsuccinate decreases obviously at 633nm.We thereafter established a spectrophotometry for the determination of erythromycin ethylsuccinate content.When the concentration of erythromycin ethylsuccinate is in the range of 0.9-150μg·mL^（-1）,the Beer′s Law is obeyed,the correlation coefficient is 0.9998,the detection limit is 0.19μg·mL^（-1）,and the apparent molar absorptivity of the complex is 4.77×10^（4 ）L·mol^（-1）·cm^（-1）.The recovery is 98.6%-105.3%,and the relative standard deviation is 2.2%in the determination of erythromycin ethylsuccinate content in erythromycin ethylsuccinate tablets by this method.