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Abdullah NS, Hassan MA, Hassan RO. Spectrophotometric determination of chlorthalidone in pharmaceutical formulations using different order derivative methods. ARAB J CHEM 2017; 10:S3426-33. [DOI: 10.1016/j.arabjc.2014.02.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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AL Azzam KM, Aboul-Enein HY. Simultaneous determination of atenolol and amiloride by capillary electrophoresis with capacitively coupled contactless conductivity detection (C4D). Methods Mol Biol 2013; 919:67-78. [PMID: 22976091 DOI: 10.1007/978-1-62703-029-8_7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Capillary electrophoresis coupled with a capacitively coupled contactless conductivity detector (CE-C(4)D) has been employed for the determination of the β-blocker drugs (atenolol and amiloride) in pharmaceutical formulations. 150 mM acetic acid was used as background electrolyte. The influence of several factors (detector excitation voltage and frequency, buffer concentration, applied voltage, capillary temperature, and injection time) was studied. Non-UV absorbing L-valine was used as an internal standard; the analytes were all separated in less than 7 min. The separation was carried out in normal polarity mode at 28 °C, 25 kV, and using hydrodynamic injection (25 s). The separation was effected in a bare fused-silica capillary 75 μm × 52 cm. The CE-C(4)D method was validated with respect to linearity, limit of detection and quantification, accuracy, precision, and selectivity. Calibration curves were linear over the range 5-250 μg mL(-1) for the studied analytes. The relative standard deviations of intra- and inter-day precisions of migration times and corrected peak areas were less than 6.0%. The method showed good precision and accuracy and was successfully applied to the simultaneous determination of the β-blocker drugs in different pharmaceutical tablets.
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Affiliation(s)
- Khaldun M AL Azzam
- School of Chemical Sciences, Universiti Sains Malaysia, Penang, Malaysia
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Elgawish MS, Mostafa SM, Elshanawane AA. Simple and rapid HPLC method for simultaneous determination of atenolol and chlorthalidone in spiked human plasma. Saudi Pharm J 2010; 19:43-9. [PMID: 23960741 DOI: 10.1016/j.jsps.2010.10.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2010] [Accepted: 10/18/2010] [Indexed: 10/18/2022] Open
Abstract
A simple, sensitive and rapid chromatographic method was developed and validated for the simultaneous quantification of atenolol and chlorthalidone in human plasma using hydrochlorothiazide as internal standard (IS). The method utilized proteins precipitation with acetonitril as the only sample preparation involved prior to reverse phase-HPLC. The analytes were chromatographed on Shim-pack cyanopropyl column with isocratic elution with 10 mM KH2PO4 (pH 6.0) - methanol (70:30, v/v) at ambient temperature with flow rate of 1 mL min(-1) and UV detection at 225 nm. The chromatographic run time was less than 10 min for the mixture. The calibration curves were linear over the range of 0.1-10 μg mL(-1). The method was validated in terms of accuracy, precision, absolute recovery, freeze-thaw stability, bench-top stability and re-injection reproducibility. The within- and between-day accuracy and precision were found to be within acceptable limits <15%. The analytes were stable after three freeze-thaw cycles (deviation <15%). The proposed method was specific for the simultaneous determination of atenolol and chlorthalidone in human plasma where there was no interference from endogenous biological substances.
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Affiliation(s)
- Mohamed S Elgawish
- Pharmaceutical Chemistry Department, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
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Al Azzam KM, Saad B, Aboul-Enein HY. Simultaneous determination of atenolol, chlorthalidone and amiloride in pharmaceutical preparations by capillary zone electrophoresis with ultraviolet detection. Biomed Chromatogr 2010; 24:977-81. [DOI: 10.1002/bmc.1395] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Al Azzam KM, Saad B, Aboul-Enein HY. Simultaneous determination of atenolol and amiloride in pharmaceutical preparations by capillary zone electrophoresis with capacitively coupled contactless conductivity detection. Biomed Chromatogr 2010; 24:948-53. [DOI: 10.1002/bmc.1390] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Al Azzam K, Elbashir AA, Elbashir MA, Saad B, Abdul Hamid S. Simultaneous Determination of Atenolol and Chlorthalidone in Pharmaceutical Preparations by Capillary-Zone Electrophoresis. ANAL LETT 2009. [DOI: 10.1080/00032710902961065] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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7
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Khuroo A, Mishra S, Singh O, Saxena S, Monif T. Simultaneous Determination of Atenolol and Chlorthalidone by LC–MS–MS in Human Plasma. Chromatographia 2008. [DOI: 10.1365/s10337-008-0755-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
A validated GC-MS method for the analysis of urinary metabolites of alkyl benzenes is reported. Metabolites for exposure to toluene, xylene and ethylbenzene were analyzed simultaneously using stable isotope substituted internal standards. The method entailed acidic deconjugation of urine samples followed by extractive alkylation with pentafluorobenzyl bromide as alkylating agent. The resulting pentafluorobenzyl derivatives of ortho-, meta-, para-cresol, mandelic acid (MA), hippuric acid (HA) and ortho-, meta-, para-methylhippuric acid (MHA) were then quantified by SIM. Optimized reaction conditions for the extractive alkylation step are reported. The derivatives were found to be sufficiently stable for overnight batch analysis. The LODs were below 0.1 micromol/L for the cresols and below 1 micromol/L for MA and the HAs. Within-batch precision for o-MHA was 7%, for m-MHA 5%, for p-MHA 5.2% and below 5% for the rest of the analytes.
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Affiliation(s)
- Adriaan A S Marais
- Department of Chemical Pathology, University of Pretoria, Pretoria, South Africa
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Moidoveanu SC, David V. Derivatization Reactions for Analytes with Various Functional Groups. Sample Preparation in Chromatography. Elsevier; 2002. pp. 639-845. [DOI: 10.1016/s0301-4770(02)80020-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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11
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Müller RK, Grosse J, Thieme D, Lang R, Teske J, Trauer H. Introduction to the application of capillary gas chromatography of performance-enhancing drugs in doping control. J Chromatogr A 1999; 843:275-85. [PMID: 10399856 DOI: 10.1016/s0021-9673(99)00498-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Performance-enhancing drugs banned by antidoping rules are detected in doping control preferably by hyphenated chromatographic techniques, capillary gas chromatography in particular. Based on the prohibited classes of substances and on the general aspects of sample collection and preparation, a survey is given about the usual procedures of screening, identification and confirmation of the most important doping agents: stimulants, narcotics, anabolics, diuretics, beta-blockers. In addition to gas chromatography itself, the application of various MS techniques doping is outlined.
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Affiliation(s)
- R K Müller
- Institute of Doping Analysis, Kreischa, Germany
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Segura J, Ventura R, Jurado C. Derivatization procedures for gas chromatographic-mass spectrometric determination of xenobiotics in biological samples, with special attention to drugs of abuse and doping agents. J Chromatogr B Biomed Sci Appl 1998; 713:61-90. [PMID: 9700553 DOI: 10.1016/s0378-4347(98)00089-9] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The development of low cost MS detectors in recent years has promoted an important increase in the applicability of GC-MS system to analyze for the presence of foreign substances in the human body. Drugs and toxic agents are in vivo metabolized in such a way that more polar compounds are usually formed. Derivatization of these metabolites is often an unavoidable requirement for gas chromatographic analysis. Application of derivatization methods in recent years has been relevant, especially for silylation, acylation, alkylation and the formation of cyclic or diastereomeric derivatives. Given the relevance of drug of abuse testing in modern toxicology, main derivatization procedures for opiates, cocaine, cannabis, amphetamines, benzodiazepines and LSD have been reviewed. Papers describing the analyses of drugs of abuse in matrixes other than blood, such as hair or sweat, have received special attention. Advances in derivatization for sports drug testing have been particularly relevant for anabolic steroids, diuretics and corticosteroids. Among the several methodologies applied, the formation of trimethylsilyl, perfluoroacyl or methylated derivatives have proved to be both versatile and extensively used. Further advances in derivatization for GC-MS applications in clinical and forensic toxicology will depend on the one hand on the degree of further use of GC-MS for routine applications and, on the other hand, on the alternative progress made for developments in LC-MS or CE-MS. Last but not least, the appearance of comprehensive libraries in which reference spectra for different derivatives of many drugs and their metabolites are collected will have an important impact on the expansion of derivatization in GC-MS for toxicological applications.
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Affiliation(s)
- J Segura
- Institut Municipal d'Investigació Mèdica IMIM, Drug Research Unit, Barcelona, Spain
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Giachetti C, Tenconi A, Canali S, Zanolo G. Simultaneous determination of atenolol and chlorthalidone in plasma by high-performance liquid chromatography. Application to pharmacokinetic studies in man. J Chromatogr B Biomed Sci Appl 1997; 698:187-94. [PMID: 9367207 DOI: 10.1016/s0378-4347(97)00298-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
An HPLC method developed to detect in a single run both atenolol and chlorthalidone, extracted from plasma, using two detectors (UV for chlorthalidone and fluorometric for atenolol) connected in series, is described. The drugs were separated on an ODS column at room temperature using a 0.05 M sodium dodecyl sulphate in phosphate buffer (pH 5.8)-n-propanol (95:5, v/v) solution, delivered at a flow-rate of 1.3 ml/min. Having ascertained the sensitivity (10 ng/ml of both drugs) and the intra-day reproducibility (pre-study validation), the reliability of the method was verified by inter-day assays (within-study validation) carried out during the analysis of plasma samples collected from healthy volunteers after single-dose treatment with atenolol+chlorthalidone tablets (pharmaceutical preparations containing 100+25 mg and 50+12.5 mg of the two drugs, respectively).
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Affiliation(s)
- C Giachetti
- Istituto di Ricerche Biomediche A. Marxer, RBM S.p.A, Ivrea (TO), Italy
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Abstract
Since the inclusion of diuretics in the list of banned substances in sports in 1988, a large number of screening and confirmation procedures to detect the presence of these substances in urine samples have been developed. In this paper, a review of the analytical methodology described to analyze diuretics is presented. The paper has been focused on the needs of doping control and mainly screening procedures including sample preparation and liquid or gas chromatographic separation have been considered. More relevant papers using capillary zone electrophoresis have been also considered. Mass spectrometry is mandatory in doping control for confirmation purposes, and finally, mass spectrometric techniques described for diuretics have been reviewed.
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Affiliation(s)
- R Ventura
- Department de Farmacologia i Toxicologia, Universitat Autonoma de Barcelona, Spain
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Abstract
The effects of the calcium antagonist, felodipine, and hydrochlorothiazide (HCTZ) on natriuresis/diuresis and blood pressure were evaluated in 12 healthy subjects. The investigation was designed as a double-blind, three-way, randomised, crossover study, and all comparisons were performed against placebo. Urine volume, urine sodium excretion, heart rate and blood pressure were measured after a single dose of felodipine 10 mg, HCTZ 12.5 mg or placebo as well as during steady-state conditions (6 days of treatment with felodipine 10 mg b.i.d., HCTZ 12.5 mg b.i.d. or placebo). A significant increase in natriuresis was seen in the first 4 h after a single dose of felodipine and HCTZ, and the effect of felodipine was approximately 40% that of HCTZ. When the entire 24-h period after a single dose was studied, there was a significant increase in natriuresis after HCTZ, but not after felodipine, compared with placebo. A significant increase in diuresis was found in the first 4 h after a single dose of HCTZ, but not after felodipine, compared with placebo. Under steady-state conditions, there were no statistically significant differences between felodipine and placebo or HCTZ and placebo when the 24-h period, as a whole was considered. Potassium excretion was not affected by any of the drugs. Felodipine caused a significant decrease in diastolic blood pressure in this study. This was not the case for HCTZ or placebo.
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Affiliation(s)
- B Hasselgren
- Astra Hässle AB, Clinical Pharmacology, Mölndal, Sweden
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Lisi AM, Kazlauskas R, Trout GJ. Diuretic screening in human urine by gas chromatography-mass spectrometry: use of a macroreticular acrylic copolymer for the efficient removal of the coextracted phase-transfer reagent after derivatization by direct extractive alkylation. J Chromatogr 1992; 581:57-63. [PMID: 1430008 DOI: 10.1016/0378-4347(92)80447-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A simple and efficient procedure has been developed for the derivatization of diuretic agents in human urine by direct extractive alkylation and their detection by gas chromatography-mass spectrometry. The procedure is an improvement over previous extractive alkylation methods because of the development of a simple clean-up step using a macroreticular acrylic copolymer (SM-7 resin) to remove the coextracted phase-transfer reagent from the organic phase after derivatization. With 1 ml of sample the method gives detection limits in the range 10-50 ng/ml for acetazolamide, probenecid, dichlorphenamide, hydroflumethiazide, furosemide, chlorthalidone, bumetanide, hydrochlorothiazide, quinethazone, bendroflumethiazide, metolazone and cyclopenthiazide.
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Affiliation(s)
- A M Lisi
- Australian Government Analytical Laboratory, Pymble, N.S.W
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Lisi AM, Trout GJ, Kazlauskas R. Screening for diuretics in human urine by gas chromatography-mass spectrometry with derivatisation by direct extractive alkylation. J Chromatogr 1991; 563:257-70. [PMID: 2055991 DOI: 10.1016/0378-4347(91)80033-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A rapid, sensitive and reliable gas chromatographic-mass spectrometric (GC-MS) screening procedure for diuretics in human urine has been developed. The procedure uses derivatisation by extractive methylation directly from the urine. The suitability of a number of phase transfer reagents and solvents were studied for the detection of sixteen diuretics. The results obtained indicate that the screening procedure employing tetrahexylammonium hydrogensulphate at pH 12 with methyl iodide in toluene at room temperature was the most effective. This method gives selectivity and sensitivities down to 0.03-0.1 microgram/ml and provides a substrate suitable for GC-MS confirmation without further manipulation. The application of the method is demonstrated by the screening of urine for bumetanide, ethacrynic acid, acetazolamide, chlorothiazide and hydrochlorothiazide.
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Affiliation(s)
- A M Lisi
- Australian Government Analytical Laboratories, Pymble, N.S.W
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Quaglia MG, Farina AM, Fanali S. Determination of chlorthalidone and its impurities in bulk and in dosage forms by high-performance thin-layer chromatographic densitometry. J Chromatogr A 1988; 456:435-9. [PMID: 3243881 DOI: 10.1016/0021-9673(86)80045-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- M G Quaglia
- Dipartimento di Studi Farmaceutici, Università degli Studi La Sapienza, Rome, Italy
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Muirhead DC, Christie RB. Simple, sensitive and selective high-performance liquid chromatographic method for analysis of chlorthalidone in whole blood. J Chromatogr 1987; 416:420-5. [PMID: 3611275 DOI: 10.1016/0378-4347(87)80530-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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Strojny N, de Silva JA. Determination of diclofensine, an antidepressant agent, and its major metabolites in human plasma by high-performance liquid chromatography with fluorometric detection. J Chromatogr 1985; 341:313-31. [PMID: 4030982 DOI: 10.1016/s0378-4347(00)84045-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
A sensitive and selective high-performance liquid chromatographic assay was developed for the determination of diclofensine (I) and its key metabolites in human plasma. The assay involves deproteinization of plasma, overnight Glusulase incubation to hydrolyze the major metabolite (I-B-glucuronide), extraction of the parent compound and its deconjugated metabolites (I-A, I-B and I-C) from the alkalinized aqueous phase into diethyl ether-ethanol (95:5), the residue of which (containing compounds I, I-A, I-B and I-C) is alkylated with 2-iodopropane dissolved in acetone, using solid potassium hydroxide as a catalyst. The compounds are extracted from the reaction mixture into diethyl ether, after adding ethanol-water-acetic acid (55:40:5), the residue of which is dissolved in 0.05 M sulfuric acid, and reacted with mercuric acetate at 100 degrees C, which oxidizes tertiary tetrahydroisoquinolines to their 3,4-dihydroisoquinoline derivatives, followed by a photochemical reaction in the same solution to form intensely fluorescent isoquinolinium derivatives. An aliquot of this reaction mixture is injected onto a reversed-phase high-performance liquid chromatography column (5-microns Nova-Pac C13 phase in a radial compression cartridge, 10 cm X 8 mm), using the mobile phase 0.25 M triethylammonium phosphate (pH 2.5)-0.25 M acetic acid-methanol-acetonitrile-tetrahydrofuran (150:350:125:375:25). The void volume (Vo) is approximately 1.4 min and the retention times (tR) of the respective isoquinolium derivatives of diclofensine (I) are ca. 3.5 min, internal standard (II) ca. 4.2 min, nordiclofensine (I-A) ca. 5 min, while the phenolic metabolites I-B and I-C give peaks at 6.4 min and 10.4 min, respectively. The derivatives are detected by fluorescence. The method was used to determine plasma concentrations of the parent drug (I) and its major phenolic metabolite I-B (aglycone) in plasma in two normal volunteers following a single oral 45-mg dose and following seven consecutive days of oral dosing of 45 mg three times a day as part of a multiple ascending dose tolerance study.
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Abstract
Methods for the determination of cardiovascular drugs in blood and plasma are critically reviewed with emphasis on gas and liquid chromatographic techniques. The importance of the various procedures is discussed, in particular sample work-up where the conditions for isolation and derivatization of the compounds are decisive for the accuracy and precision of the methods. Compared with other assay techniques chromatographic methods are generally to be preferred owing to their better selectivity. In the review the following groups are discussed: digitalis glycosides, antiarrhythmic agents, beta-adrenoceptor antagonists, vasodilating agents, antihypertensive compounds, and diuretics.
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Singer JM, O'hare MJ, Rehm CR, Zarembo JE. Chlorthalidone. Elsevier; 1985. pp. 1-36. [DOI: 10.1016/s0099-5428(08)60575-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Marzo A, Treffner E, Neggiani PP, Staibano G. Gas--liquid chromatographic evaluation of lofemizole in biological samples for pharmacokinetic investigations. Comparison of two analytical methods. J Chromatogr 1984; 310:51-9. [PMID: 6501522 DOI: 10.1016/0378-4347(84)80067-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The present paper reports the analytical conditions allowing lofemizole, a new non-steroidal anti-inflammatory drug, to be evaluated in biological fluids for pharmacokinetic and bioavailability investigations. The first approach led to an N-methyl derivative of lofemizole which could be successfully analysed by gas--chromatography employing a flame-ionization detector, reaching a sensitivity of 2 micrograms/ml. The second approach led to the N-(2-chlorobenzoyl) derivative of lofemizole which was suitable for pharmacokinetic investigation using gas--liquid chromatography with electron-capture detection, and reaching a much higher sensitivity of 10 ng/ml of plasma. Recovery of the extraction, reproducibility and specificity were all satisfactory with both methods. Since the first method employing flame-ionization detection was suitable for pharmacokinetic investigations in animal species, this paper describes both methods on a comparative basis.
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Bauer J, Quick J, Krogh S, Shada D. Stability-indicating assay for chlorthalidone formulation: evaluation of the USP analysis and a high-performance liquid chromatographic analysis. J Pharm Sci 1983; 72:924-8. [PMID: 6620149 DOI: 10.1002/jps.2600720821] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An investigation of the USP assay of chlorthalidone tablets showed that variable degradation of chlorthalidone occurred during assay preparation. The degradation products were isolated and identified. A stability-indicating high-performance liquid chromatographic (HPLC) assay which separates the degradation products from chlorthalidone was developed and used to examine the present USP preparation. The HPLC assay is suggested as an alternate.
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Marzo A, Quadro G, Treffner E. Gas-liquid chromatographic evaluation of fenquizone in biological samples for pharmacokinetic investigations. J Chromatogr 1983; 272:95-102. [PMID: 6841550 DOI: 10.1016/s0378-4347(00)86106-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Extractive alkylation was carried out on fenquizone, a sulphonamide diuretic, in order to devise a suitable method for its determination in pharmacokinetic and bioavailability studies. After extraction as a tetramethyl derivative, fenquizone was evaluated by gas-liquid chromatography with a 63Ni electron-capture detector, which enables a limit of detection of 2 ng/ml of plasma or urine to be achieved. Linearity was verified in a range of 50- 10,000 pg for each injection with a fenquizone/internal standard ratio ranging from 4:1 to 1:4. Determination is very rapid, as one analysis only takes 5 min. The preliminary results of the pharmacokinetic study performed in a volunteer human subject after a single oral administration of the drug are presented in this paper in terms of the plasma levels and the cumulative urinary excretion.
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Guerret M, Julien-Larose C, Kiechel JR, Lavène D. Determination of 3-hydroxy-guanfacine in biological fluids by electron-capture gas-liquid chromatography. J Chromatogr 1982; 233:181-92. [PMID: 6761349 DOI: 10.1016/s0378-4347(00)81745-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An electron-capture gas-liquid chromatographic method was developed for measuring 3-hydroxy-guanfacine, the main metabolite of guanfacine in human plasma and urine. After extraction, the metabolite was derivatized by condensing the amidino group with hexafluoroacetylacetone and by methylating the NH and OH groups with methyl iodide. The obtained derivative possessed good bioanalytical gas chromatographic properties, using a capillary column. The O-glucuronide was measured after enzymatic hydrolysis. Unchanged guanfacine could be determined in urine together with its 3-hydroxy metabolite by this method.
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Hulshoff A, Förch AD. Alkylation with alkylhalides as a derivatization method for the gas chromatographic determination of acidic pharmaceuticals. J Chromatogr A 1981; 220:275-311. [PMID: 7035475 DOI: 10.1016/s0021-9673(00)81927-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The various types of alkylation reactions with alkyl halides and their application in the gas chromatographic analysis of acidic compounds of pharmaceutical interest are reviewed. An extensive survey of the use of these methods for the analysis of various (classes of) compounds is given, with special reference to their determination in biological matrices.
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Floberg S, Hartvig P, Lindström B, Lönner-Holm G, Odlind B. Extractive alkylation of 6-mercaptopurine and determination in plasma by gas chromatography-mass spectrometry. J Chromatogr 1981; 225:73-81. [PMID: 7197685 DOI: 10.1016/s0378-4347(00)80245-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
An analytical procedure was developed for the determination of 6-mercaptopurine in plasma. Owing to the polar character and low plasma concentration of the compound, extraction and derivatization was carried out directly from the plasma sample by extractive alkylation. Determination was made using gas chromatography-mass spectrometry with multiple-ion detection. Conditions with respect to the rate of formation and the stability of the derivative formed in the extractive alkylation step were evaluated. The selectively of the method to azathioprine and to metabolites was thoroughly investigated. No 6-mercaptopurine was formed from azathioprine added to water or plasma and run through the method. The method enables the detection of 2 ng of 6 mercaptopurine in a 1.0-ml plasma sample. Quantitative determinations were done down to 10 ng/ml 6 mercaptopurine in plasma.
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Vessman J. Chapter 13 Biomedical applications of the electron-capture detector. Electron Capture Theory and Practice in Chromatography. Elsevier; 1981. pp. 275-357. [DOI: 10.1016/s0301-4770(08)60137-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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31
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Riva E, Farina PL, Sega R, Tognoni G, Bastain W, McAinsh J. Pharmacokinetics of atenolol in hypertensive subjects with and without co-administration of chlorthalidone. Eur J Clin Pharmacol 1980; 17:333-7. [PMID: 7418712 DOI: 10.1007/bf00558445] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The pharmacokinetics of atenolol with and without the co-administration of chlorthalidone were studied in five hypertensive subjects. Concomitant administration of chlorthalidone appears to have little if any effect on the pharmacokinetics of atenolol during treatment for 7 days. The atenolol elimination half-lives were 6.7 +/- 1.1 and 6.3 +/- 0.9 h, respectively, with and without chlorthalidone. Two healthy volunteers also received a single 50 mg oral dose of chlorthalidone. Their blood profiles and pharmacokinetics were similar to those observed in hypertensive subjects, but a statistically significant difference (p < 0.01) was found between the urinary excretion half-lives of chlorthalidone. This difference may be because chronic administration of the drug caused saturation of red cell binding.
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Guelen PJ, Baars AM, Vree TB, Nijkerk AJ, Vermeer JM. Rapid and sensitive determination of chlorthalidone in blood, plasma and urine of man using high-performance liquid chromatography. J Chromatogr 1980; 181:497-503. [PMID: 7391165 DOI: 10.1016/s0378-4347(00)81156-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Abstract
Niclosamide (5,2'-dichloro-4'-nitrosalicylanilide), formulated as the ethanolamine salt, is one of the most effective and widely used molluscicides for the control of snail vectors of schistosomiasis, a parasitic disease afflicting over 200 million people in more than 70 countries. This report details the development of a sensitive, specific analytical method for the evaluation of niclosamide formulations and assessment of the impact of residues on the environment. Efficient (greater than 85%) phase-transfer, N,O-dimethylation of niclosamide and the synthesized 5-deschloro analog internal standard, followed by gas-liquid chromatographic separation and electron-capture detection, permits the determination of as little as 10 ppb analyte in fortified, stagnant water. Tetrabutylammonium chloride was the phase-transfer agent, while methyl iodide was the methylating agent of choice among four investigated.
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Mulley BA, Parr GD, Rye RM. Pharmacokinetics of chlorthalidone. Dependence of biological half life on blood carbonic anhydrase levels. Eur J Clin Pharmacol 1980; 17:203-7. [PMID: 6767611 DOI: 10.1007/bf00561901] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The relationship between the whole blood concentration of carbonic anhydrase and the biological half life of chlorthalidone has been investigated in six volunteers. A linear relationship was observed and on the basis of this, a pharmacokinetic model to explain the long and variable biological half life of chlorthalidone is proposed and discussed.
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Mulley BA, Parr GD, Rye RM. A MODEL FOR THE EFFECT OF CARBONIC ANHYDRASE ON THE DISPOSITION OF CHLORTHALIDONE IN MOTHERS AND NEONATES. J Clin Pharm Ther 1979. [DOI: 10.1111/j.1365-2710.1979.tb00158.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Stenberg P, Jönsson TE, Nilsson B, Wollheim F. Determination of ketoprofen in plasma by extractive methylation and electron-capture gas chromatography. J Chromatogr A 1979; 177:145-8. [PMID: 536441 DOI: 10.1016/s0021-9673(00)92612-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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39
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Fagerlund C, Hartvig P, Lindström B. Extractive alkylation of sulphonamide diuretics and their determination by electron-capture gas chromatography. J Chromatogr A 1979; 168:107-16. [PMID: 762226 DOI: 10.1016/s0021-9673(00)80698-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The extractive alkylation of 11 sulphonamide diuretics has been evaluated using tetrabutylammonium, tetrapentylammonium or tetrahexylammonium as counter ion at different pH values and methyl iodide in methylene chloride as the organic phase. The sulphonamides are methylated within 20 min with tetrahexylammonium as counter ion in 0.2 M sodium hydroxide at 50 degrees. The derivatives have been identified by mass spectral and nuclear magnetic resonance analysis. Relative retentions of the derivatives are given using 1% SE-30 as the stationary phase. A contaminant, dimethylsulphuric acid, occurs in methyl iodide and seriously disturbs the gas chromatographic analysis. The application of the extrative alkylation to biological samples is demonstrated by the direct analysis of acetazolamide in serum. 0.1 M tetrapentylammonium in 0.5 M sodium hydroxide is suitable as the aqueous phase with 1.6 M methyl iodide as alkylating reagent in methylene chloride. The trimethyl derivative of acetazolamide formed has been determined by electron-capture gas chromatography down to 0.5 microgram/ml in a 0.1-ml serum sample. The relative standard deviation at the 10 microgram/ml level is 6.6% (n = 10).
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O'Hare MJ, Tan E, Moody JE. Quantitative determination of chlorthalidone in pharmaceutical dosage forms by high-pressure liquid chromatography. J Pharm Sci 1979; 68:106-8. [PMID: 758442 DOI: 10.1002/jps.2600680136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A reliable and selective high-pressure liquid chromatographic procedure for the quantitative determination of chlorthalidone in pharmaceutical dosage forms is described. A comparison of this stability-indicating procedure with the USP spectrophotometric assay is presented for chlorthalidone tablets and chlorhalidone tablets containing reserpine.
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Abstract
Regulation of acidity for protonation of the free N4-amine can provide for the selective liquid--liquid extraction isolation of a sulfonamide from its degradation products. This principle is applied for the stability-indicating determination of sulfacetamide in the presence of sulfanilamide, sulfaquinoxaline in feed, and sulfabromomethazine in dosage forms. In solution, sulfabromomethazine can exhibit photodecomposition to sulfamethazine. The mean relative errors of the these methods and the precision, represented by relative standard deviations, are each typically less than 2%.
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Abstract
A method for determining indomethacin in serum has been developed, involving extractive alkylation, in which indomethacin is converted into its ethyl ester, and subsequent gas chromatographic determination of the ester. The method is specific and permits the determination of amounts down to 50 ng/ml in serum. The indomethacin concentration in serum was followed for 24 h after oral and rectal application and the results are compared with those reported in the literature.
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Mulley BA, Parr GD, Pau WK, Rye RM, Mould JJ, Siddle NC. Placental transfer of chlorthalidone and its elimination in maternal milk. Eur J Clin Pharmacol 1978; 13:129-31. [PMID: 658109 DOI: 10.1007/bf00609757] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A gas chromatographic method has been used to determine chlorthalidone in amniotic fluid, maternal and foetal blood at delivery, and in maternal milk and blood three days after delivery, following the administration of chlorthalidone to nine pregnant women suffering from toxaemia of pregnancy. Placental transfer of chlorthalidone and elimination in maternal milk have been shown and the implications of these factors are discussed. An explanation has been proposed for our observations that foetal blood levels of the drug are about 15% of those in maternal blood.
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Fleuren HL, Van Rossum JM. Determination of chlorthalidone in plasma, urine and red blood cells by gas chromatography with nitrogen detection. J Chromatogr A 1978; 152:41-54. [PMID: 649750 DOI: 10.1016/s0021-9673(00)85332-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
A sensitive and selective gas chromatographic method is described for determining the diuretic and antihypertensive drug chlorthalidone in plasma, urine and erythrocytes. Use is made of an alkali flame ionization detector (nitrogen detector), and the chlorthalidone and internal standard are chromatographed as methyl derivatives. Down to 10 ng of drugs in the biological sample can be measured accurately, with a standard deviation of 5%. Because the concentration of chlorthalidone found in erythrocytes is 50-100 times higher than that in plasma, the influence of haemolysis on the plasma concentration has been investigated. In addition, a pharmacokinetic study with human volunteers revealed that the apparent concentration of the drug found in plasma can be much too low (by more than 50%), if the plasma is not separated from the erythrocytes immediately after venipuncture. Precautions to be observed to ensure correct handling of blood samples (so that results for plasma concentrations will be reliable) are stressed. The findings have application in kinetic studies on chlorthalidone.
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Hartvig P, Gyllenhaal O, Hammarlund M. Determination of saccharin in urine by electron-capture gas chromatography after extractive methylation. J Chromatogr A 1978; 151:232-6. [PMID: 641131 DOI: 10.1016/s0021-9673(00)85388-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Riess W, Dubach UC, Burckhardt D, Theobald W, Vuillard P, Zimmerli M. Pharmacokinetic studies with chlorthalidone (Hygroton) in man. Eur J Clin Pharmacol 1977; 12:375-82. [PMID: 598410 DOI: 10.1007/bf00562454] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Abstract
A sensitive and specific GLC method for the determination of urinary chlorthalidone levels was developed using on-column methylation. Chlorthalidone is converted to a tetramethylated derivative with trimethylanilinium hydroxide in methanol. This method which permits the determination of as little as 0.1 microgram of chlorthalidone/ml of dog urine, should be adequate for use with human subjects receiving a clinical dose.
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Abstract
Chlorthalidone was analyzed in the concentration range of 0.1-3.0 microgram/ml with a precision of +/- 0.05 microgram/ml. Chlorthalidone inhibition of the enzymatic hydrolysis rate of p-nitrophenyl acetate by bovine erythrocyte carbonic anhydrase was used as a basis for the determination. The amount of p-nitrophenol formed was measured by monitoring the absorbance at 400 nm, and its formation rate was proportional to the chlorthalidone concentration. The mixing of the enzyme, substrate, and sample, the incubation of the reaction mixture, and the recording of the absorbance were automated. A survey of urine samples from 26 normal human subjects did not reveal any endogenous substances that interfered with the assay. Analyses of urine samples from six subjects after oral administration of 100 mg of chlorthalidone indicated rapid absorption and a biphasic elimination. The alpha-phase half-life was 1.5 hr, and the beta-phase half-life was 35 hr.
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Abstract
The following alkylation methods for the determination of indometacin in plasma by electron capture gas chromatography are compared: 1, alkylation with diazopropane; 2, extractive alkylation; 3, alkylation by a solid-liquid phase transfer catalysed process. The drug in plasma at pH 4.0 is initially extracted with heptane containing 5% n-pentanol. The methyl ester of indometacin is based as internal standard. After alkylation to the propyl ester according to one of the three alkylation methods, indometacin can be determined down to 5 ng per sample by electron capture gas chromatography. The relative standard deviations (n = 10) at the 200 ng level are 5.1% for the alkylation with diazopropane, 7.5% for the extractive alkylation technique and 3.5% for the alkylation by the solid-liquid phase transfer catalysed process. The comparatively low value obtained by the last method indicates that decomposition of indometacin can be avoided under such mild conditions.
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Degen PH, Schweizer A. Quantitative determination of drugs in biological materials by means of extractive alkylation and gas-liquid chromatography. J Chromatogr A 1977; 142:549-57. [PMID: 914935 DOI: 10.1016/s0021-9673(01)92067-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Analytical methods utilizing extractive alkylation followed by gas-liquid chromatography are described for the quantitative determination of (neo)sulfalepsine and its metabolites, chlorthalidone and chlorquinaldol. The applications described indicate that, for the use of this technique, careful optimization and the introduction of a suitable internal standard at the beginning of the analytical manipulations are essential.
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