Mobile phase versus stationary phase approaches to the direct injection of biological fluids in liquid chromatography

Fett, Joseph J.; Hischak, Frank; Love, L. J. Cline.

doi:10.1002/bmc.1130050105

Cited by 8 publications

(3 citation statements)

References 25 publications

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“…Interaction of HCT with many drugs has been reported; to study the suspected interaction of the uricostatic drug allopurinol with HCT (Loffler et al, 1989;Vries et al, 1989), an assay for the determination of this drug in plasma and urine was developed. Several methods for the measurement of IICT in biological fluids have been previously reporteddetermination by high performance liquid chromatography (HPLC) (Alton et ul., 1986;Azumaya, 1990;Barbhaiya el al., 1981;Christophersen et al, 1977;Cooper et al, 1976Cooper et al, , 1989Fett et al, 1991;Henion and Maylin 1980;Koopmans et al, 1984;Shiu et al, 1986;Stewart and Clark, 1986;Van der Meer and Clark, 1987;Yamazaki et al, 1984), gas-liquid chromatography (Lindstrom et al, 1991;Henion arid Maylin 1980).…”

Section: ~ ~~mentioning

confidence: 96%

“…Interference from other drugs has not been investigated in most of the reported HPLC methods, although the separation of 23 diuretics was described (Cooper et al, 1989) it was applied for urine screening only. Extraction procedures in most previous methods used multiple liquid extractions or a combination of column and liquid extraction procedures instead of the presently described single step; a direct injcction method (Fett et al, 1991) has been described only for hydrochlorothiazide analysis in urine samples but without investigating the possible interferences. …”

Section: Interfering Substancesmentioning

confidence: 99%

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Simple determination of hydrochlorothiazide in human plasma and urine by high performance liquid chromatography

Vries¹,

Voss²

1993

Biomedical Chromatography

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The diuretic drug hydrochlorothiazide (HCT) is used mainly for treatment of mild to moderate hypertension and is usually administered with other drugs. An assay for the determination of HCT in human plasma and urine by high performance liquid chromatography (HPLC) has been developed. Samples were purified by solvent extraction and analysed by reversed phase HPLC with ultraviolet detection, using hydroflumethiazide as the internal standard; plasma was eluted using gradient elution and urine was analysed isocratically. The method is simple to perform, is sensitive (detection limit 0.01 micrograms/mL in plasma and 0.2 micrograms/mL for urine); it showed good reproducibility (3-8%). A great number of drugs did not interfere with the assay and the method was used for pharmacokinetic studies in healthy subjects, but samples from patients can also be analysed with high selectivity.

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Section: ~ ~~mentioning

confidence: 96%

Section: Interfering Substancesmentioning

confidence: 99%

Simple determination of hydrochlorothiazide in human plasma and urine by high performance liquid chromatography

Vries¹,

Voss²

1993

Biomedical Chromatography

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“…few (1)(2)(3)(4)(5)(6)(7)(8) referred to evaluation in biological fluids; of these. even fewer have been used to study pharmacokinetics at the lowest dose (25 mg) administered.…”

Section: Introductionmentioning

confidence: 99%

Liquid extraction and HPLC-DAD assay of hydrochlorothiazide from plasma for a bioequivalence study at the lowest therapeutic dose

Medvedovici

Mircioiu

David

et al. 2000

Eur. J. Drug Metab. Pharmacokinet.

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The main parameters considered in optimizing the liquid extraction and quantitative assay were the yield, precision, limit of quantification, time required for extraction and concentration, and quantity of solvent. The influence on these parameters of the following factors was examined: nature of the extracting solvent, quantity of solvent, co-extraction solvent, and duration of stirring. Instead of equilibrium parameters of the involved thermodynamic system, a kinetic approach was preferred in terms of the effective partition 'constant', which is not really constant but a function of time and extraction conditions. The final selected method, considered to be rapid and simple, was applied to determine the pharmacokinetics of hydrochlorotiazide (HCT) after administration of Capozide (Bristol-Myers Squibb) tablets containing 50 mg Captopril and 25 mg HCT, to 4 healthy volunteers. The results obtained were in accordance with the pharmacokinetic parameters of HCT reported in the literature.

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Automated HPLC analyses of drugs of abuse via direct injection of biological fluids followed by simultaneous solid‐phase extraction and derivatization with fluorescence detection

Bourque

Krull

Feibush³

1994

Biomedical Chromatography

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An automated system is described for the simultaneous extraction and derivatization of nucleophilic compounds from various biological media. The method includes the use of a solid-phase reagent containing a 9-fluorenylacetate activated ester. The reagent is based on a controlled pore, polystyrene divinylbenzene support prepared through a silica template procedure. An X-Y-Z robotic arm equipped with a needle is used in conjunction with a syringe pump for aspirating and dispensing samples and standards into the HPLC system. A precolumn cartridge containing the solid-phase reagent is put on-line in place of the fixed-volume injection loop. Injections of biological fluids such as urine or plasma with minimal sample treatment and handling are made directly into this reactor. The analytes are derivatized as they are extracted, allowing virtually unlimited sample volumes to be injected. The polymeric cartridge can be used for up to 100 injections without accruing unacceptable reductions in sensitivity. A detection limit of 500 p.p.t. (parts per trillion) of amphetamine in urine was achieved with this system.

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Mobile phase versus stationary phase approaches to the direct injection of biological fluids in liquid chromatography

Cited by 8 publications

References 25 publications

Simple determination of hydrochlorothiazide in human plasma and urine by high performance liquid chromatography

Simple determination of hydrochlorothiazide in human plasma and urine by high performance liquid chromatography

Liquid extraction and HPLC-DAD assay of hydrochlorothiazide from plasma for a bioequivalence study at the lowest therapeutic dose

Automated HPLC analyses of drugs of abuse via direct injection of biological fluids followed by simultaneous solid‐phase extraction and derivatization with fluorescence detection

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