Losartan potassium and hydrochlorothiazide are often combined in pharmaceutical formulations for the treatment of hypertension. Therefore, the determination of these compounds in a single run is highly desirable for rapid quality control applications. The present study describes an ultra-fast (ca. 85 injections h-1) and environmentally friendly method based on capillary electrophoresis (CE) with capacitively coupled contactless conductivity detection for simultaneous quantification of potassium, losartan and hydrochlorothiazide. Cation (potassium) and anions (losartan and hydrochlorothiazide) were analyzed in a single run using a background electrolyte composed by 10.0 mmol L-1 boric acid (pH = 9.0, adjusted with sodium hydroxide). The limits of detection were 4.0, 3.0 and 10.0 μmol L-1 for potassium, losartan and hydrochlorothiazide, respectively. The proposed method is simple, fast, with minimal waste generation, and accurate (recovery values between 98 and 102%). The results obtained with the CE method were statistically similar (95% confidence level) to those obtained by high-performance liquid chromatography (losartan and hydrochlorothiazide) and flame photometry (potassium).

This paper presents a simple and low-cost capillary electrophoresis method for ultra-fast simultaneous determination of naphazoline (NPZ) and one of the following active ingredients: diphenhydramine (DIP), pheniramine (PHEN) or chlorpheniramine (CPHEN). The proposed method is based on capillary electrophoresis with capacitively coupled contactless conductivity detection (CE-C4D) equipped with a short length capillary column (10 cm). One sample can be analyzed every 35 s (ca. 100 injections per hour) with resolutions between peaks greater than 1.4. The optimized background electrolyte (BGE) was composed by 20 mmol L-1 histidine and 10 mmol L-1 3,4-dimethoxycinnamic acid (pH = 9.5, adjusted with NaOH). Limits of detection were 25 µmol L-1 for NPZ, DIP, and PHEN and 13 µmol L-1 for CPHEN. The results obtained with the developed procedure were compared to those obtained by high-performance liquid chromatography (HPLC) and no statistically significant differences were observed (95% confidence level).