• Archives of Pharmacal Research
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• v.13 no.3
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• pp.215-220
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• 1990

Two different, derivative spectrophotometric and gas-liquid chromatographic, procedures for direct quantitation of caffeine and some commonly dispensed antihistaminics in bulk forms, in their laboratory prepared mmixtures and in dosage formulations, have been investigated. The limit, sensitivity reproducibility and accuracy of each method were studied for each individual drug substance and in some usual pharmaceutical formulations.

• YAKHAK HOEJI
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• v.33 no.3
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• pp.156-160
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• 1989

A gas-chromatographic determination method of thiamin which use a quantitative cleavage of thiamin to 4-methyl-5-(2-hydroxyethyl)thiazol [I] and solvent extraction of the analyte prior to GC injection was modified. A column chromatographic procedure using a reversed phase, high capacity solid phase cartridge was applied to the clean-up of the analyte. Thiazol derivative[I] was quantitatively recovered upon the column method. Acetanilide, an internal standard, has a good recovery through the analytical procedure. The method has analytical precision of 2% or less in the coefficient of variation.

• YAKHAK HOEJI
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• v.23 no.1
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• pp.7-10
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• 1979

A gas chromatographic determination of dienestrol in dienestrol cream has been studied. Dienestrol cream was dissolved in pyridine and silylation was done by using N, O-bis (trimethylsilyl) trifluoroacetamide. The derivative was injected into 3% silicone OV-17 column for chromatographic estimation. The dienestrol peak was found to be well separated from the other components of the cream. The detection limit was obtained to be $5.6{\times}10^{11}$ mol of dienestrol for this method. As there is no need for prior separation procedure, this experiment is extremely simple and less time consuming as compared to the conventional methods for estimation of dienestrol in cream.

• Journal of the Korean Home Economics Association
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• v.7 no.1
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• pp.74-77
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• 1969

• Proceedings of the PSK Conference
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• 2002.04a
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• pp.135.1-135.1
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• 2002

• YAKHAK HOEJI
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• v.28 no.4
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• pp.243-248
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• 1984

For gas chromatographic determination with the sulfur-specific flame photometric detector, nine ${\beta}$-lactam antibiotics without ${\alpha}$-amino group were esterified with borontrifluoride-methanol complex and then N-benzoylated with benzoyl chloride. The gas chromatographic separation of these products was successfully carried out on various silicon polymers (OV-1, OV-101, OV-17, OV-225, and QF-1) coated on the acid washed, silanized diatomite. The structure of the esterified and N-benzoylated product was confirmed by mass spectromer.

• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.155-160
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• 2010

A gas chromatographic-mass spectrometric (GC-MS) method was developed for the simultaneous determination of valproic acid (VPA) and its toxic metabolites, 4-ene-VPA and 2,4-diene-VPA in rat plasma. Extraction was performed in weak acidic condition (pH 5.2) to avoid degradation of 4-ene-VPA and 2,4-diene-VPA. The recoveries for 4-ene-VPA and 2,4-diene-VPA were more than 70% and that for VPA was 33-42%. R value for each compounds exceeded 0.998 in calibration curve during all the analysis. Accuracy and precision ranged from 88.3 to 113.2% and from 2.16 to 14.2%, respectively The method was successfully applied to monitor plasma concentrations of VPA, 4-ene-VPA and 2,4-diene-VPA after intravenous administration of VPA at the dose of 100 mg/kg, suggesting that these toxic metabolites may involved in the hepatotoxicity induced by VPA.

• YAKHAK HOEJI
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• v.16 no.1
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• pp.55-64
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• 1972

The determination method of l-ephedrine and dl-methylephedrine by gas chromatography was developed, using reactive alkaline precolumn packed with celite 545 containing KOH. Symmetrical peaks were achieved under the condition, inlet temperature, $180^{\circ}C$-$230^{\circ}C$; column temperature, $180^{\circ}C$- $160^{\circ}C$; carrier gas flow rate, 30ml/minute. The peaks of the salts coincided with those of bases. When this method was applied to preparations, using d-dimethylaminobenzaldehyde as inner standard, good results were obtained. The relative retention times of l-ephedrine and dl-methylephedrine to p-dimethyl aminobenzaldehyde were 0.50 and 0.65 respectively.

• YAKHAK HOEJI
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• v.30 no.5
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• pp.214-219
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• 1986

A gas chromatographic procedure is described for the quantitative analysis of ephedrine hydrochloride, pseudoephediiiie hydrochloride and norephedrine hydrochloride in pharmaceutical preparations. The procedure was based upon the determination of thioureas formed from amines and phenylisothiocyanate. The recoveries of ephedrine, pseudoephedrine and norephedrine from pharmaceutical preparations were 100.7(S.E. 0.9), 99.5(0.8), 99.1(0.8) and 99.1%(O.9), respectively. The high accuracy and precision of this assay were inherent in the flame photometric detectors normally used in gas chromatography.

• Archives of Pharmacal Research
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• v.17 no.2
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• pp.76-79
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• 1994

The concentration of styrne in blood of the occupationally syrene-exposed workers was checked by gas chromatographic headspace analysis. Mandelic acd in urine, that is a major metabolite of styrene, and hippuric acid wre also analyzed by high performance liquid chromatography. For the biological monitoring of styrene-exposed workers, the routine method of the quantitative determination of styrene nad its metabolites in the biolgical samples were studied.