目的：研究和寻找精密而简便地测定增效联磺片中磺胺甲　唑、磺胺嘧啶及甲氧苄氨嘧啶3种成分含量的方法。方法：采用毛细管区带电泳法，以0.05mol·L^-1磷酸盐缓冲液(pH=6.0)作运行液,恒定电压20kV(运行电流95μA-105μA)，并与药品标准规定的方法相比较。结果：3种成分在3min-8min之内完全达到基线分离，各组分溶液浓度在70μg·ml^-1-750μg·ml^-1范围内，浓度与峰面积之间呈良好的线性关系。选用乙酰苯胺作内标物，可测定3种成分的含量，批内RSD均小于1%(n=9)，3种成分的加样回收率不低于96.45%,RSD均小于3%(n=12)。结论：结果表明毛细管区带电泳(CZE)法准确可靠，方便易行，可进行增效联磺片中3种成分的含量测定，而药品标准中规定的方法只能测定两种磺胺药的总量和甲氧苄氨嘧啶的含量。

OBJECTIVE: To study a method for determination of sulfamethoxazole, sulfadiazine and trimethoprim tablets, a compound tablet of sulfamethoxazole, sulfadiazine and trimethoprim. METHOD: A capillary zone electrophoresis (CZE) method was used to assay three components of this compound preparation. RESULTS: The complete separation of components was achieved with 0.05 mol·L^-1 pH 6.0 running phosphate buffer and a constant voltage of 20 kV (current of 95 μA～105 μA). The retention times of individual components were between three and eight minutes and a good linearity was shown between concentration and peak area in the concentration range over 70 μg·ml^-1～750 μg·ml^-1. When acetanilide was used as internal standard, the relative standard deviation (RSD) of each component determined in a batch was less than 1% (n=9). The recovery of each component was not less than 96.45% with RSD less than 3%. The analytical results obtained from 6 samples of clinical use were inconsistent with those by standard method, however the quantity of each sulfa drug was obtained by CZE method. CONCLUSION: The results showed this method is accurate, simple, and rapid. When this method is used, the quantity of each three components is determined, but by the standard method, only the total quantity of the two sulfa drugs is obtained.