Determination Of Diuretics Research Articles

Solvent Bar Microextraction Combined with HPLC-DAD for Simultaneous Determination of Diuretics in Human Urine and Plasma Samples.

A simple and powerful microextraction procedure, the solvent bar microextraction (SBME), was used for the simultaneous determination of two diuretics, furosemide and spironolactone in human urine and plasma samples, using high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). The appropriate amount (2 μL) of 1-octanol as an organic solvent confined within 2.5 cm of a porous hollow fiber micro-tube, sealed at both ends was used for this procedure. The conditions for the SBME were optimized in water and the analytical performance was examined in spiked human urine and plasma samples. The optimized method exhibited good linearity (R2> 0.997) over the studied range of higher than 33 to 104μg L-1 for furosemide and spironolactone in urine and plasma samples, illustrating a satisfactory precision level with RSD values between 2.1% and 9.1%. The values of the limits of detection were found to be in the range of 6.39 to 9.67μg L-1, and extraction recovery ˃ 58.8% for both diuretics in urine and plasma samples. The applicability and effectiveness of the proposed method for the determination of furosemide and spironolactone in patient urine samples were tested. In comparison with reference methods, the attained results demonstrated that SBME combined with HPLC-DAD was proved to be simple, inexpensive, and promising analytical technology for the simultaneous determination of furosemide and spironolactone in urine and plasma samples.

Determination of diuretics in human urine using HPLC coupled with magnetic solid-phase extraction based on a metal-organic framework.

Magnetic solid-phase extraction (MSPE) employing a metal-organic framework (Fe3 O4 @UiO-66-OH) combined with high-performance liquid chromatography was developed for the determination of trace diuretics in urine. The structure and properties of Fe3 O4 @UiO-66-OH were investigated using X-ray diffraction, infrared spectroscopy, scanning electron microscopy and vibrating sample magnetometry. Magnetic solid-phase extraction conditions, such as adsorbent amount and solution pH, were optimized using response surface methodology. Under the optimal conditions, the method resulted in excellent linearity with a high correlation coefficient (r > 0.99), satisfactory intraday repeatability (1.78-2.99%), low limits of detection (0.08-0.23 ng/ml), and good recoveries in urine samples (between 93.5 and 103%). Fe3 O4 @UiO-66-OH based on MSPE is a novel pretreatment technique for the detection of trace diuretics in urine.

Determination of diuretics and laxatives as adulterants in herbal formulations for weight loss

A new method is described for the determination of the most common diuretic and laxative adulterants found in formulations of anorexics and antidepressants. The method is based on the separation of furosemide, hydrochlorothiazide, chlorthalidone and amiloride (diuretics), phenolphthalein (laxative), amfepramone (anorexic) and fluoxetine and paroxetine (antidepressants) by capillary zone electrophoresis with capacitively coupled contactless conductivity detection. The method showed a precision ranging from 1.9% to 6.9% for a concentration of 25 mg/L, 0.6% to 5.3% for a concentration of 50 mg/L and 1.6% to 6.0% for a concentration of 100 mg/L for all analytes. The accuracy was 99% for amiloride, 102% for chlorthalidone, 101% for hydrochlorothiazide, 101% for furosemide, 94% for phenolphthalein, 105% for fluoxetine, 114% for paroxetine and 117% for amfepramone. The method allowed the drugs to be determined in the formulations at concentrations higher than 5.1 mg/kg for amiloride, 7.7 mg/kg for chlorthalidone, 6.8 mg/kg for hydrochlorothiazide, 10.7 mg/kg for furosemide, 8.4 mg/kg for phenolphthalein, 11.0 mg/kg for fluoxetine, 9.4 mg/kg for paroxetine and 11.0 mg/kg for amfepramone. Three of the 26 analysed herbal formulations were found to be adulterated (not declared on the label) with the diuretic hydrochlorothiazide. Five other samples contained diuretics declared on the label on the formulation. Thus, a total of eight samples, which were marketed as natural products, contained diuretics (declared or not) on the formulation.

Study of the matrix effect on the determination of nonconjugated xenobiotics in human urine by high-performance liquid chromatography/tandem mass spectrometry

Factors affecting the sensitivity and selectivity of the determination of diuretics, anabolic steroids, central nervous system stimulants, and narcotics in the analysis of human urine extracts by high-performance liquid chromatography-tandem mass spectrometry with atmospheric pressure electrospray ionization and recording of positive ions were investigated. Mass spectra were obtained for all of the test compounds; the characteristic ions, retention times, detection limits, degree of ionization suppression by the matrix, the extraction of the analytes from human biological fluids were determined for all analytes; the selectivity and specificity of determination were evaluated.

Determination of diuretics in human urine by hollow fiber-based liquid–liquid–liquid microextraction coupled to high performance liquid chromatography

In competition sports, a diuretic is a substance widely prohibited by the World Anti-Doping Agency (WADA). In this paper, a sensitive, rapid and convenient analytical method for the determination of acidic [furosemide (FUROS) and bumetanide (BUMET)] and basic [triamterene (TRIAM)] diuretics in human urine was developed by hollow fiber-based liquid-liquid-liquid microextraction (LLLME) coupled with HPLC-UV. The LLLME conditions, such as the organic extraction solvent, the acidity and basicity of the donor- and acceptor-phases, stirring speed, extraction time and ionic strength, were studied in detail. Under the optimum conditions, the linear ranges of furosemide, bumetanide and triamterene were 1.2-250, 5.0-250 and 5.0-500 ng mL(-1), respectively. The detection limits were 0.5 ng mL(-1) for furosemide, 1.2 ng mL(-1) for bumetanide and 2.0 ng mL(-1) for triamterene. The LLLME obtained a great improvement of the detection limits for all the analytes considered here, to the ng mL(-1) level, which almost reaches the level of the LC-MS method. This new LLLME method provided very high enrichments: 117-fold for furosemide, 175-fold for bumetanide and 68-fold for triamterene. Since the hollow fiber membrane was sealed, it could be used for extracting the diuretics directly from 'dirty' human urine samples without any clean-up procedures. With LLLME-HPLC, the corresponding recoveries ranged from 79.2 to 109% with the RSDs not exceeding 5.5% for the three diuretics in the spiked urine samples. The method was successfully applied to analyse the amounts of the three diuretics in real urine samples of volunteers after oral drug-taking. This new method proves to be sensitive and reliable and thus renders a very suitable means for the determination of trace diuretics in human urine based on the common HPLC instrument.

A new method for screening and determination of diuretics by on‐line CE‐ESI‐MS

A rapid, high-resolution and effective new method for analyzing 12 diuretics by CE-ESI-MS was established in this paper. Ten diuretics (except two neutral compounds) could be fast separated by CE with a DAD at 214 nm with a 20 kV voltage within 6 min, using a 50 microm id and 48.5 cm effective length uncoated fused-silica capillary in a 40 mM ammonium formate buffer (pH 9.40). CE was coupled to the mass spectrometer applying an orthogonal electrospray interface with a triple-tube sheath liquid arrangement. The sheath liquid was composed of isopropanol-water (1:1 v/v) containing 30 mM acetic acid with a flow rate of 4 microL/min. Mass spectrum was employed in the positive mode and both full scan mode and SIM scan mode were utilized. All 12 diuretics could be detected and confirmed by MS in a single analysis. Under optimized conditions, LODs for the 12 diuretics were in the range of 0.13-2.7 micromol/L at an S/N of 3, and the correlation coefficients R(2 )were between 0.9921 and 0.9978. The RDSs (n = 5) of the method was 0.24-0.94 % for migration times and 1.6-8.8 % for peak areas. The recoveries of spiked samples of 12 diuretics were between 72.4% and 118%. The real urine samples were injected directly for analysis, with only simple filtration through a 0.22 microm membrane filter in order to remove solid particles, which may cause capillary blockage. Based on the migration times and characteristic ions, the diuretics in urine samples were detected successfully. This CE-ESI-MS method for analyzing diuretics will hopefully be applied to doping control.

Determination and characterization of diuretics in human urine by liquid chromatography coupled to pneumatically assisted electrospray ionization mass spectrometry

The aim of this work was to develop a method for the characterization and determination of diuretics in human urine samples by liquid chromatography (LC) coupled to pneumatically assisted electrospray ionization (ES) mass spectrometry (MS). The diuretics studied were substances forbidden by the IOC such as trichlormethiazide, furosemide, canrenoic acid, benzthiazide, bendroflumethiazide, bumetanide, etacrynic acid and spironolactone. For this purpose, the operational parameters of electrospray, such as counter electrode voltage, capillary voltage, sample cone voltage and source temperature, were optimized in order to obtain the best signal stability and the highest sensitivity for the greatest number of diuretic agents. The optimized separation method was successfully coupled with the MS system to analyze the above-mentioned diuretics extracted from spiked urine samples by a liquid extraction and clean-up procedure at basic pH, using ethyl acetate as solvent and the salting-out effect (NaCl). The mass spectra obtained provide adequate information for identification purposes. Positive urine samples obtained from athletes were also analyzed. The presence of these substances in human urine was confirmed by this method, making LC/ES-MS an analytical tool to be considered in the area of antidoping control.

Simultaneous Determination of the Diuretics Triamterene and Furosemide in Pharmaceutical Formulations and Urine by HPLC-EC

Abstract A high performance liquid chromatographic method with amperometric detection has been developed for the simultaneous determination of two diuretics: triamterene and furosemide, using a μ-Bondapak C18 column. The mobile phase consisted of a mixture water:acetonitrile, 30:70, 5mM in KH2PO4/K2HPO4, pH 5.5 pumped at a flow rate of 1 mL/min. The amperometric detector, equipped with a glassy carbon electrode, was operated at +1300 mV. The method was applied to the determination of both diuretics in the pharmaceutical formulation Salidur (triamterene 25 mg and furosemide-xanthinol 77.6 mg) and real urine samples obtained from a healthy volunteer after the ingestion of a single dose of Salidur. Using a simple liquid-liquid extraction procedure, good recovery and separation from interferences found in urine matrix is achieved and the simultaneous determination of both compounds is possible. Reproducibility is good with relative standard deviations lower than 1.5% intra-day and 5% inter-day, and the method...