Analysis of the 1,4-benzodiazepines by methods based on hydrolysis

Gasparič, J.; Zimák, Jiří

doi:10.1016/0731-7085(83)80039-9

Cited by 22 publications

(9 citation statements)

References 104 publications

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“…Therefore, in order to have optimal sensitivity, it is necessary to optimize the parameters affecting the hydrolysis and other chemical reactions. According to the literature, the hydrolysis temperature of 100 °C in acidic medium has been extensively used 36. Thus, the temperature and time of the hydrolysis were fixed at 100 °C and 1 h, respectively, and the influence of HCl concentration was examined by taking varying volumes of 6 M HCl (in the range of 0.1–2.0 ml).…”

Section: Resultssupporting

confidence: 92%

“…The spectrophotometric methods used for determining individual BZPs are generally based on their acid hydrolysis followed by a ring opening reaction and the subsequent determination of the obtained benzophenone. The benzophenone is diazotized with nitrous acid and then coupled with different chromogenic reagents 5, 36. These reactions take place at different pH values; in fact, the diazotized benzophenone is formed at very low pH (<1), whereas the coupled product requires an alkaline medium (pH > 12) 5.…”

Section: Resultsmentioning

confidence: 99%

“…The reaction conditions for the hydrolysis of BZPs vary considerably for individual compounds 36. Therefore, in order to have optimal sensitivity, it is necessary to optimize the parameters affecting the hydrolysis and other chemical reactions.…”

Section: Resultsmentioning

confidence: 99%

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Applying cloud point extraction technique for the extraction of oxazepam from human urine as a colour or fluorescent derivative prior to spectroscopic analysis methods

Tabrizi

Harasi

2011

Drug Testing and Analysis

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Two new methods based on cloud point extraction (CPE) technique were developed and optimized for the extraction and preconcentration of oxazepam from human urine, as an azo or fluorescent derivative. The first method is a spectrophotometric one, which is based on the acid hydrolysis of the oxazepam to a benzophenone, diazotization of the benzophenone, and then the coupling with oxine to form an azo dye. The second method is a spectrofluorimetric one, which involves reduction of the target compound using Zn°/HCl at room temperature with the formation of a highly fluorescent derivative. The main factors affecting the chemical reactions and CPE were investigated and optimized systematically. Under optimum experimental conditions, the calibration graphs were linear in the range of 0.1 to 1.5 (0.05 to 2.0) µg/ml with correlation coefficients of 0.9989 (0.9985), for the CPE-spectrophotometric (CPE-spectrofluorimetric) method. The limit of detection was found to be 0.034 (0.018) µg/ml and the relative standard deviation was calculated to be 1.35 (2.52)%. Recoveries in the spiked samples ranged from 87 to 94%. Finally, the proposed methods were applied to the determination of oxazepam in human urine.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

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Applying cloud point extraction technique for the extraction of oxazepam from human urine as a colour or fluorescent derivative prior to spectroscopic analysis methods

Tabrizi

Harasi

2011

Drug Testing and Analysis

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“…It is worthwhile to mention the importance of amide group substituents of the diazepinic ring in the behavior of the thienodiazepines because Clotiazepam, with a methyl substituent, undergoes hydrolysis in alkaline media and at room temperature, whereas the derivative 5-(2-chlorophenyl) -1,3-dihydro -2H-h e n o [ 2,3-e] [ 1,4]diazepin-2-one (TDO) [ 6 ] , without substituents in the amide group, does not undergo such a hydrolysis process. Cyclic voltammetry and differential pulse polarography have been the most widely used electroanalytical techniques for kinetic studies, but reports concerning kinetic studies of 1,4-benzodiazepine derivatives are scarce [7-lo].…”

Section: -Methy1-5-o-chlorophenyl-7-ethyl-l2-dihydro-3h-thienomentioning

confidence: 99%

Electroanalytical study of the hydrolysis of the thienodiazepine clotiazepam

1991

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The hydrolysis reaction in an alkaline medium of the thiendodiazepine Clotiazepam has been studied by differential pulse polarography at various pH values at 25, 37, and 5OOC. In an alkaline medium, Clotiazepam exhibits two well-defined polarographic peaks, attributed to the azomethine group of the parent compound and the carboxylic group of the hydrolysis product, with a potential difference of 0.160 V, practically constant in the pH range studied. Kinetic studies of the reversible hydrolysis process based on the current changes with time of the first polarographic peak indicate that the process is a pseudo-first-order reaction with a rate constant dependent on hydroxide ion concentration. Arrhenius parameters were also calculated. A voltammetric study of the hydrolysis product has been carried out, and determination methods have been developed by differential pulse voltammetry and differential pulse polarography. which dlffers from benzodiazepines only in having a thiophene nucleus bound to the diazepinic moiety instead of a benzene nucleus. It is used as a minor tranquilizer 12, 31.Clotiazepam experiences hydrolysis in alkaline media. This fact is an important dlfference with respect to most 1 ,Cbenzodiazepine derivatives, which undergo hydrolysis in acidic media [ 41 or a process catalyzed by acid and bases, as in the case of benzodiazepinooxazoles [5].It is worthwhile to mention the importance of amide group substituents of the diazepinic ring in the behavior of the thienodiazepines because Clotiazepam, with a methyl substituent, undergoes hydrolysis in alkaline media and at room temperature, whereas the derivativewithout substituents in the amide group, does not undergo such a hydrolysis process.Cyclic voltammetry and differential pulse polarography have been the most widely used electroanalytical techniques for kinetic studies, but reports concerning kinetic studies of 1,4-benzodiazepine derivatives are scarce [7-lo].In this work, a kinetic study of the hydrolysis process of the compound was carried out by differential pulse ' To whom correspondence should be addressed.polarography, following the current changes with time. To develop determination methods for the compound, an electroanalytical study of the hydrolysis product was made. Apparatus and ReagentsPrinceton Applied Research Corporation (PAR) Model 174 polarographic analyzer, a PAR Model 303A SMDE cell and a Houston Omnigraphic X-Y recorder were used to carry out the kinetic study and the voltammetric measurements of the hydrolysis product.A threeelectrode thermostated cell of 15 mL capacity, containing a dropping mercury electrode (DME: capillary tube of inside diameter 0.015 mm) as the working electrode, a saturated Ag/AgCl/KCl as the reference electrode, and a platinum wire as auxiliary electrode was employed. A Metrohm glassy carbon electrode served as working electrode in the voltammetric measurements.Polarography was performed in the differential polarographic mode. A pulse of 25 mV was applied using a drop time of 0.5 second, and the...

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“…The drug may inhibit monosynaptic and polysynaptic reflexes by acting as inhibitory neuronal transmitters or by blocking excitatory synaptic transmission. The drug may also directly depress motor nerve and muscle function [1,2]. Clidinium bromide (3-[(hydroxy-diphenylacetyl)-oxy]-1-methyl-1-azoniabicylo-[2.2.2]octane bromide is effective for anxiety-related conditions including spastic colon [3].…”

Section: Introductionmentioning

confidence: 99%