Fluorometric assay of .alpha.-methylene carbonyl compounds with N1-methylnicotinamide chloride

Nakamura, Hiroshi; Tamura, Zenzo

doi:10.1021/ac50036a027

Cited by 29 publications

(16 citation statements)

References 21 publications

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“…Nakamura described the application of a fluorometric method of the reaction of N 1 -methylnicotinamide chloride (NMNCl) for the analysis of various compounds containing α-methylene carbonyl functional groups [1]. Nakamura also made qualitative tests on the reaction mechanism and identified the cyclized α-adduct fluorophore [1].…”

Section: Introductionmentioning

confidence: 99%

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Fluorometric Determination of Drugs Containing α-Methylene Sulfoxide Functional Groups Using - Methylnicotinamide Chloride as a Fluorogenic Agent

Elokely

Eldawy

Elkersh

et al. 2012

ISRN Analytical Chemistry

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A simple fluorometric method, using N 1 -methylnicotinamide chloride (NMNCl) as a fluorogenic reagent, has been developed, adapted, and validated for the quantitative estimation of drugs containing α-methylene sulfoxide functional groups. The proposed method has been applied successfully to the determination of sulindac (1), omeprazole (2), lansoprazole (3), pantoprazole (4), and rabeprazole (5) in the pure form, laboratory-prepared mixtures, pharmaceutical dosage forms, spiked human plasma samples, and in hospitalized patient's or volunteer's blood. For the standard solutions of 1, 2, 3, 4, and 5, the method showed linearity over concentration ranging between 1-50 μg/mL, 50-1200 ng/mL, 100-1500 ng/mL, 10-1500 ng/mL, and 20-2200 ng/mL, respectively. For the spiked human plasma of 1, 2, 3, 4, and 5, the linearity was shown over concentration ranging between 1-50 μg/mL, 75-1200 ng/mL, 100-1400 ng/mL, 10-1500 ng/mL, and 50-2100 ng/mL, respectively. The method showed good accuracy, specificity, and precision in both laboratory-prepared mixtures and spiked human plasma samples. The proposed method is simple, does not need sophisticated instrumentation, suitable for quality control application, bioavailability, and bioequivalency studies. Besides, the sensitivity and detection limits are comparable to sophisticated chromatographic methods.

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Section: Introductionmentioning

confidence: 99%

“…Nakamura also made qualitative tests on the reaction mechanism and identified the cyclized α-adduct fluorophore [1]. This reaction was not tested before for compounds containing α-methylene adjacent to other functional groups.…”

Section: Introductionmentioning

confidence: 99%

Fluorometric Determination of Drugs Containing α-Methylene Sulfoxide Functional Groups Using - Methylnicotinamide Chloride as a Fluorogenic Agent

Elokely

Eldawy

Elkersh

et al. 2012

ISRN Analytical Chemistry

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show abstract

“…[31][32][33][34] The mechanism of the reaction, 31,33) as well as its application on acetophenone, 33) and on few bulk active pharmaceutical ingredients (APIs) 35) were reported. Nevertheless, this reaction found limited application in pharmaceutical analysis.…”

Section: Resultsmentioning

confidence: 99%

Spectrofluorimetric Determination of Drugs Containing Active Methylene Group Using N1-Methyl Nicotinamide Chloride as a Fluorigenic Agent

Dawya

Mabrouk

Barbary

2006

CHEMICAL & PHARMACEUTICAL BULLETIN

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A spectrofluorimetric method was described for the determination of drugs containing active methylene groups adjacent to carbonyl groups. The method was applied successfully to the determination of three life saving cardiovascular drugs, with narrow therapeutic indices: pentoxifylline (I), propafenone hydrochloride (II) and acebutolol hydrochloride (III), in laboratory-prepared mixtures, in commercial tablets and in plasma samples. The method involved the reaction of each of the tested drugs with N 1 -methyl nicotinamide chloride (NMNCl) in the presence of alkali, followed by addition of formic acid, where highly fluorescent reaction products were produced. The produced fluorescence were measured quantitatively at 472 nm (l l ex 352 nm), 409 nm (l l ex 310 nm) and 451 nm (l l ex 266 nm) for (I), (II), and (III) respectively. The method was linear over concentration ranges of 10-1000 m mg/ml , 0.2-12 m mg/ml and 0.08-10 m mg/ml in standard solutions for (I), (II), and (III) respectively. In spiked human plasma samples, calibration graphs were linear over concentration ranges of 20-1000 m mg/ml, 0.2-15 m mg/ml and 0.08-10 m mg/ml for (I), (II), and (III) respectively. The method showed good accuracy, specificity and precision in both laboratory-prepared mixtures and spiked human plasma samples. The proposed method is simple, with low instrumentation requirements, suitable for quality control application, bioavailability and bioequivalency studies.

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“…1). [16][17][18] The method was applied to a preliminaly study on the effect of foods on the N-nitrosation of MU under the conditions simulated to those of the stomach. 19 Fresh orange juice and milk were tested as model foods because they are reported to be protective factors concerning gastric cancer in humans.…”

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confidence: 99%

Fluorometric Determination of N-Nitroso-N-methylurea with Nicotinamide and Acetophenone

Sano

Nakamura

2001

ANAL. SCI.

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It is well known that dietary secondary amides are readily nitrosatable intragastrically owing to the presence of acidic gastric juice and salivary nitrite ion; 1,2 also, many Nnitrosamides are direct-acting mutagens which show carcinogenicity to various laboratry animals. 3 Therefore, in addition to the roles of Helicobacter pylori infection, 4,5 Nnitrosamides formed in the stomach have been postulated to be potent etiological agents for gastric cancer in humans. 1,2,4,5 N-Nitroso-N-methylurea (NMU) is a strong carcinogenic Nnitrosamide; the formation of NMU in stomach has been noted because the dietary intake 6 and endogenous formation 7,8 of a precursor N-methylurea (MU) were suggested. Therefore, because the effects of foods on the N-nitrosation of MU under gastric conditions should be clarified, a suitable assay system is necessary. For the determination of N-nitrosamides including NMU, conventional photometric 9,10 and fluorometric 11 methods as well as various chromatographic methods [12][13][14][15] have been reported. In this paper, a sensitive and selective fluorometric method for the determination of NMU is described. The method is based on the N-methylation reaction of nicotinamide with NMU under a weak alkaline condition to form N 1 -methylnicotinamide (NMN) and a subsequent condensation reaction with acetophenone under an alkaline condition, followed by an acid treatment to give a fluorescent 2,7-naphthyridine derivative (Fig. 1). [16][17][18] The method was applied to a preliminaly study on the effect of foods on the N-nitrosation of MU under the conditions simulated to those of the stomach. 19 Fresh orange juice and milk were tested as model foods because they are reported to be protective factors concerning gastric cancer in humans. 1 Experimental ApparatusA Shimadzu RF-510 spectrofluorometer (Shimadzu, Kyoto, Japan) was used with a 0.4 × 1 cm quartz cell at room temperature. The spectral bandwidths were 5 nm (excitation) and 10 nm (emission). All fluorescence excitation and emission spectra were uncorrected. ChemicalsNicotinamide, N-nitroso-N-methylurethane, 1-iodobutane, 1,2-epoxyoctane (Tokyo Kasei, Tokyo, Japan), 2-methoxyethanol, acetophenone, acetonitrile, ethanol, dichloromethane, heptane, potassium hydroxide, sodium nitrite, potassium thiocyanate, sodium azide (Kanto Chemical, Tokyo, Japan), NMU, N-nitroso-N-ethylurea, N-nitroso-N-butylurea Shinjuku, Japan A fluorometric method for the determination of N-nitroso-N-methylurea (NMU) has been developed. It is based on the N-methylation reaction of nicotinamide with NMU and a subsequent condensation reaction with acetophenone, followed by an acid treatment to form a fluorescent 2,7-naphthyridine derivative. This method enabled the determination of NMU in the range 0.05 -2 nmol/200 µl with a relative standard deviation of ca. 3%. It was applied to the determination of NMU formed from a precursor N-methylurea (MU) under simulated gastric conditions containing nitrite and thiocyanate ions at pH 3.0 in the presence of fresh orange juice and...

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Fluorometric assay of .alpha.-methylene carbonyl compounds with N1-methylnicotinamide chloride

Cited by 29 publications

References 21 publications

Fluorometric Determination of Drugs Containing α-Methylene Sulfoxide Functional Groups Using - Methylnicotinamide Chloride as a Fluorogenic Agent

Fluorometric Determination of Drugs Containing α-Methylene Sulfoxide Functional Groups Using - Methylnicotinamide Chloride as a Fluorogenic Agent

Spectrofluorimetric Determination of Drugs Containing Active Methylene Group Using N1-Methyl Nicotinamide Chloride as a Fluorigenic Agent

Fluorometric Determination of N-Nitroso-N-methylurea with Nicotinamide and Acetophenone

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