Voltammetric determination of nitrosocimetidine in simulated gastric juice

Walash, M. I.; Belal, F.; Ibrahim, F.; Hefnawy, Mohamed M.; Eid, Manal

doi:10.1046/j.1365-2710.2002.00432.x

Cited by 2 publications

(4 citation statements)

References 16 publications

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“…30) In recent reports, NBD-Cl was further used as a chromogenic reagent for the determination of some primary and secondary amines. [14][15][16][17][18][19][20][21][22][23][24] In the present study, DSL was found to react with NBD-Cl in borate buffer of pH 7.6 producing a yellow color with maximum absorbance at 485 nm; Method I. Figure 2a illustrates the absorption spectrum of the reaction product.…”

Section: Resultsmentioning

confidence: 88%

“…14) Moreover, the condensation product with NBD-Cl was found to be also a fluorescent derivative. NBD-Cl has been used as a derivatizing agent for many compounds either per se or in formulations and biological fluids such as lisinopril, 15) gliclazide, 16) tianeptine, 17) ranitidine and nizatidine, 18) atenolol, 19) fenetrol, 20) trimetazidine, 21) and recently befunolol, 22) some b-blockers 23) and paroxetine. 24) Sanger's reagent (DNFB) on the other hand has been applied as a chromophore reactant in the spectrophotometric determination of norfloxacin, 25) enalapril and lisinopril.…”

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confidence: 99%

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Spectrophotometric, Spectrofluorometric and HPLC Determination of Desloratadine in Dosage Forms and Human Plasma

2007

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Four sensitive, simple and specific methods were developed for the determination of desloratadine (DSL), a new antihistaminic drug in pharmaceutical preparations and biological fluids. Methods I and II are based on coupling DSL with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in borate buffer of pH 7.6 where a yellow colored reaction product was obtained and measured spectrophotometrically at 485 nm (Method I). The same product could be measured spectrofluorometrically at 538 nm after excitation at 480 nm (Method II). Methods III and IV, on the other hand, involved derivatization of DSL with 2,4-dinitrofluorobenzene (DNFB) in borate buffer of pH 9.0 producing a yellow colored product that absorbs maximally at 375 nm (Method III). The same derivative was determined after separation adopting HPLC (Method IV). The separation was performed on a column packed with cyanopropyl bonded stationary phase equilibrated with a mobile phase composed of acetonitrile-water ( (Method IV). The four developed procedures were applied for the determination of DSL in tablets without any interference from the excipients. A low LOQ is a common requirement to support a clinical development program and when this is coupled with a simple procedure for sample preparation and feasible analytical tool, they would be the requirements of an optimized analytical method. Although the previously reported methods that were applied in pharmacokinetic studies of desloratadine possess the required low LOQ, they lack the simple sample preparation and method feasibility that were obtained in our spectrofluorometric method using NBD-Cl as a derivatizing agent where a low LOQ of 0.012 mg/ml was attained which allowed the analytical determination of DSL in spiked and real human plasma. ExperimentalMaterials and Reagents All chemicals were of analytical reagent grade. Desloratadine reference standard was kindly provided by ScheringPlough Corporation, U.S.A. Aerius tablets labeled to contain 5 mg DSL per tablet were purchased from commercial sources at a local pharmacy. Plasma samples were obtained from Mansoura University Hospital, Mansoura, Egypt, and were kept frozen until use after gentle thawing. Sep-Pak ® C18 solid phase extraction cartridges, 200 mg (SPE) were purchased from Waters Corporation (Milford, MA, U.S.A.). 4-Chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) was purchased from Sigma (St. Louis, MO, U.S.A.). A stock solution containing 2 mg/ml was freshly prepared in methanol. 2,4-Dinitrofluorobenzene (DNFB) was also purchased from Sigma (St. Louis, MO, U.S.A.). A stock solution containing 0.25% (v/v) was freshly prepared in methanol. Borate buffer solutions (0.2 M) were prepared by mixing appropriate volumes of 0.2 M boric acid and 0.2 M NaOH and adjusting the pH to 7.6 and 9.0 using a pH meter.29) Formic acid 85%, acetonitrile and methanol; AR Grade, Aldrich (St. Louis, MO, U.S.A.).Apparatus A Shimadzu UV-Visible 1601 PC spectrophotometer was used for the spectrophotometric measurements (P/N 206-67001). The recording range was 0-1.0.The f...

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Section: Resultsmentioning

confidence: 88%

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confidence: 99%

Spectrophotometric, Spectrofluorometric and HPLC Determination of Desloratadine in Dosage Forms and Human Plasma

2007

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“…For these latter reasons, spectrophotometric methodologies, because of their inherent simplicity, low cost and wide availability were extensively proposed for R . HCl determination [19][20][21][22][23][24][25][26][27][28][29][30] . These methods are based on redox, coupling, charge-transfer complexation, and ion pair complexation reactions.…”

Section: Ranitidine N-(2-{[(5-dimethylamino)methyl]-2-furanyl}-methymentioning

confidence: 99%

“…As shown in this table, some of the reported procedures 20,27 have higher detection limits. Moreover, some of the reported methods are alike or more sensitive but have drawbacks such as having a narrow linear dynamic range 26 , involving extraction 19,21 or being performed at high temperatures 22,23,26 . …”

Section: Analytical Parametersmentioning

confidence: 99%

Spectrophotometric Method for Ranitidine Determination in Drugs Using Rhodamine B

Moldovan¹,

Aboul‐Enein²

2012

J. Chil. Chem. Soc.

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A new spectrophotometric method has been developed for the determination of ranitidine hydrochloride (R . HCl) in bulk drug and in tablet formulation. The proposed method involves the addition of a measured excess of bromate-bromide reagent in hydrochloric acid medium to R . HCl, followed by determination of residual bromine by reacting with a fixed amount of Rhodamine B (RB) and measuring the absorbance at λ max =557 nm. Beer's law was found in the range of 0.3-3.2 μg ml -1 of R . HCl, with a good correlation coefficient (r=0.9997). The limits of detection and quantification were calculated to be 0.08 μg ml -1 and 0.24mg ml -1 , respectively. The different experimental parameters affecting the development and stability of the proposed method were carefully studied and optimized. The validity of the proposed method tested by analyzing the pure and pharmaceutical formulations and compared well with those obtained by the official method, demonstrated good accuracy and precision.

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Voltammetric determination of nitrosocimetidine in simulated gastric juice

Abstract: The proposed method was successfully applied to study the nitrosation of cimetidine in SGJ.

Cited by 2 publications

References 16 publications

Spectrophotometric, Spectrofluorometric and HPLC Determination of Desloratadine in Dosage Forms and Human Plasma

Spectrophotometric, Spectrofluorometric and HPLC Determination of Desloratadine in Dosage Forms and Human Plasma

Spectrophotometric Method for Ranitidine Determination in Drugs Using Rhodamine B

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