差示分光光度法测定伤风止咳糖浆中盐酸异丙嗪的含量

Determination of Promethazine Hydrochloride in its Compound Syrup by Differential Spectrophotometry

盐酸异丙嗪以过氧乙酸氧化后生成其亚砜衍生物(Sulphoxide derivative),与未经氧化处理的溶液在同一波长处存在差示吸收(ΔA),其λ_(max)为336nm,而干扰组分在>300um波长段的差示吸收近于0。用峰基线法计算含量以排除氧化剂本身产生的微小干扰。盐酸异丙嗪在2～5mg/100ml浓度范围内与ΔA_(336)呈良好的线性关系(r=0.9999)。方法准确、专属性强,平均回收率为99.4%(CV=0.3%,n=9)。

Promethazine HC1 may be olidized into its sulphoxide derivative by peroxy-ace-tic acid, which showed a maximum differential absorption at 336 nm coinpared tothe solution without oxidization, there was no interference from other Constitue-nts.It Was the Peak-to-baseline method calculating the contents that may elim-inate the little effect by oxidents. There was an ideal linear relationship betw-een. the concentration in the range of 2 mg to 5 mg per 100ml and differentialabsorbances. Correlation coefficient was 0.9999. It was specific and accurate. TheAverage recovery and coefficient of variation were 99.41%. and 0.27% (n=9)respectively.