Surface modification by calcium ions—Effect on chromatographic properties of silica

Summary A liquid chromatographic method incorporating column-switching and fluorimetric detection for the determination of triamterene in untreated urine, is described. The urine samples (5 L) were directly introduced onto an Hypersil ODS-C18, 30 m (20 mm×2.1 mm I.D.) pre-column. Polar urinary compounds were removed by flushing the pre-column with water for 1 min, and the analyte was then switched onto an HP-LiChrospher RP C18,5 m (125 mm×4mm ID) analytical column using an acetonitrile/phosphate buffer gradient elution. Fluorescence detection was performed at 230 nm excitation and 430 nm emission wavelengths. The recovery of drug was 102±2% in the 0.10–20.0 g/mL concentration range, the limit of detection being 5 ng/mL. A validation of the usefulness of this procedure was accomplished by analysing urine extracts obtained from real samples.Hypersil ODS is not a product of Merck, Germany. Please give supplier (p. 5).     

Thermal study of complex formation of triamterene with β-cyclodextrin by spray-drying and co-grinding

The formation of crystalline inclusion complex of triamterene with β-cyclodextrin (β-CD) was studied, evaluating the thermal behaviour and dispersion state of this drug in different types of binary systems. Spray-drying and co-grinding (oscillating mill) mixtures of triameterene with β-CD were prepared in 1∶1 molar ratio. The changes of crystalline properties of original (untreated) triamterene, β-CD, and composites obtained by co-grinding and spray-drying were investigated in comparison with those produced in simple physical mixtures. The thermal behaviour of the different samples was investigated using DTA. X-ray diffraction was applied as a complementary technique. The results have been explained by formation of amorphous drug particles on spray-drying samples and co-grinding or alternatively by means of a solid dispersion formation or a combination of these two. A contamination effect by grinding media was also observed as increasing grinding time.     

Two‐phase and three‐phase liquid‐phase microextraction of hydrochlorothiazide and triamterene in urine samples

This paper reports the applicability of two‐phase and three‐phase hollow fiber based liquid‐phase microextraction (HF‐LPME) for the extraction of hydrochlorothiazide (HYD) and triamterene (TRM) from human urine. The HYD in two‐phase HF‐LPME is extracted from 24 mL of the aqueous sample into an organic phase with microliter volume located inside the pores and lumen of a polypropylene hollow fiber as acceptor phase, but the TRM in three‐phase HF‐LPME is extracted from aqueous donor phase to organic phase and then back‐extracted to the aqueous acceptor phase, which can be directly injected into HPLC for analysis. Under optimized conditions preconcentration factors of HYD and TRM were obtained as 128 and 239, respectively. The calibration curves were linear (R² ≥ 0.995) in the concentration range of 1.0–100 µg/L for HYD and 2.0–100 µg/L for TRM. The limits of detection for HYD and TRM were 0.5 µg/L. The intra‐day and inter‐day RSD based on four replicates were obtained as ≤5.8 and ≤9.3%, respectively. The methods were successfully applied for determining the concentration of the drugs in urine samples. Copyright © 2015 John Wiley & Sons, Ltd.     

毛细管电泳-柱端喷壁式电化学检测法用于利尿剂氢氯噻嗪和氨苯喋啶的研究

应用毛细管电泳-电化学检测法对利尿剂氢氯噻嗪和氨苯喋啶进行了研究。考察了电化学检测和电泳分离条件对氢氯噻嗪和氨苯喋啶分离、检测的影响,结果表明在最佳分离、检测条件下,两种待测物在8 min内达到基线分离。氨苯喋啶和氢氯噻嗪的检测限分别达到0.29和0.25 mg/L。对两物质于日内和日间重复测定7次,迁移时间的日内相对标准偏差(RSD)不大于1.6％,峰电流的日内RSD不大于 3.1％; 迁移时间的日间RSD不大于1.7％,峰电流的日间RSD不大于 4.9％。 将该方法用于复方氨苯喋啶成药中氨苯喋啶和氢氯噻嗪的分离和测定,成药的检测结果与标示量比较,相对误差小于4.6％。在模拟尿样中对氢氯噻嗪和氨苯喋啶进行标准溶液添加回收实验,其回收率分别为93.5%~96.7%和96.6%~97.2%,结果令人满意。     

高效液相色谱法同时测定尿液中4种肾脏病常用药物

建立了一种高效液相色谱同时测定尿液中4种肾脏病常用药物依那普利、氨苯蝶啶、呋塞米及缬沙坦含量的方法。色谱分离选用WondaSil C18-WR (150 mm×4.6 mm, 5 μ m);以10.0 mmol/L乙酸铵溶液(pH 3.90)和乙腈为流动相进行梯度洗脱,流速为1.0 mL/min,于254 nm波长下检测,18 min内实现了4种药物的分离分析。结果表明依那普利、氨苯蝶啶、呋塞米、缬沙坦分别在0.15~300 mg/L、0.05~100 mg/L、0.75~750 mg/L、0.05~100 mg/L范围内线性良好,检出限依次为1.38×10^-2、7.67×10^-3、3.69×10^-2、1.16×10^-2mg/L,平均加标回收率在89.49%~99.20%之间,相对标准偏差(RSD, n=3)在4.12%~9.44%之间。结果表明该方法样品处理简便、快速,结果准确可靠,为肾脏病患者尿液中的治疗药物浓度监测提供了一种新方法。