Two cyclodextrin micellar liquid chromatographic methods were developed and applied to the simultaneous determination of bisoprolol/hydrochlorothiazide and atenolol/chlorthalidone combinations in urine matrices without sample pretreatment. These combined β-blockers and diuretics chemotherapies are commonly used in the treatment of hypertension and cardiovascular diseases. Hybrid isocratic mobile phases containing hydroxypropyl-β-cyclodextrin, sodium dodecyl sulfate, phosphate buffer and methanol on a Luna C18 column with 0.5 mL min(-1) flow rate and 25.0°C column temperature were used. The methods were sensitive enough for the determination of analytes at the therapeutic urine levels with limits of detections down to 1.0 µg mL(-1); relative standard deviations and recoveries were ranged between 1.5-4.4% and 98.00-109.52%, respectively. Urinary excretion studies showed that the detection of drugs is possible up to 24 h after their ingestion. The selective proposed separations with less consumption of organic solvents over the hitherto ones could be attributed to the four point competitive interactions among analysts, pseudostationary phases and a real stationary phase.

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Summary. Pharmaceutical industry concerned recently with eco-friendly analytical methods to reduce the environmental pollution. The using of toxic organic solvents for the analysis of drugs is critical. In the current work, several simple and less costly approaches such as micellar and/or cyclodextrin liquid chromatography were discussed. A new eco-friendly and simple chromatographic analysis of the ternary mixture of amiloride hydrochloride (AM), atenolol (AT), and hydrochlorothiazide (HZ) in urine by hydroxypropyl-beta-cyclodextrin (HP-β-CD) bonded stationary phase was investigated. The experimental conditions were optimized and validated based on International Conference on Harmonization (ICH) Q2R1 guidelines to detect analytes by isocratic mobile phase of phosphate buffer (5.0 mmol L −1 , pH 7.0) in the presence of 0.5 mL min −1 flow rate, 25.0 °C, and 280 nm. Linearity, accuracy, and precision were found to be acceptable over the concentration range of 0.05-20.0 μg mL −1 for AM, 0.05-50.0 μg mL −1 for AT and 0.05-50.0 μg mL −1 for HZ. The proposed method was precise, selective, and sensitive enough for the routine analysis of ternary mixture at therapeutic urine levels. The inclusion complexation and the appendant hydroxyl groups of HP-β-CD were considered the main reasons for assisting in adequate separation of the drugs. On the other hand, the presence of kosmotropic phosphate ions could solubilize the protein and could strengthen the selective inclusion of drugs inside HP-β-CD cavity. Urinary excretion studies showed that the detection of drugs is possible up to 24 h after their ingestion.