Quantitative determination of nitroglycerin by capillary gas chromatography-electron capture detection

Pharmacokinetic interaction between 5-[2-propyloxy-5-(1-methyl-2-pyrollidinylethylamidosulfonyl)phenyl]-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo (4,3-d) pyrimidine-7-one (DA-8159) and nitroglycerin in rats

The pharmacokinetic interaction between 5-[2-propyloxy-5-(1-methyl-2-pyrollidinylethylamidosulfonyl)phenyl]-1-methyl-3-propyl-1,6-dihydro-7H-pyrazolo (4,3-d)pyrimidine-7-one (DA-8159), a new erectogenic, and nitroglycerin has been evaluated in rats. Male Sprague-Dawley rats received DA-8159 (30 mgkg−1) as a single intravenous or oral dose with the simultaneous single intravenous administration of nitroglycerin (2.5 mgkg−1). After simultaneous intravenous administration, the total area under the plasma concentration-time curve from time zero to time infinity (AUCinf) of DA-8159 (746 vs 457 μg min mL−1) was found to be significantly greater than with DA-8159 alone. Also, after simultaneous intravenous administration total body clearance (CL) (40.2 vs 65.6 mL min−1 kg−1), renal clearance (CLR) (1.65 vs 5.11 mL min−1 kg−1), and nonrenal clearance (CLNR) (38.3 vs 60.2 mL min−1 kg−1) of DA-8159 were significantly slower compared with DA-8159 alone. The slower CLNR of DA-8159 could have been due to the inhibition of the metabolism of DA-8159 by nitroglycerin, since DA-8159 is metabolized via CYP3A1/2 in rats and nitroglycerin inhibits CYP3A1/2 in rats. The slower CLR of DA-8159 could have been due to the urine flow rate-dependent CLR of DA-8159 in rats. After the simultaneous intravenous administration of nitroglycerin and DA-8159, the AUCinf of nitroglycerin was significantly smaller (635 vs 960 μg min mL−1), which could have been due to the cardiac output-dependent CL of nitroglycerin. However, after the oral administration of DA-8159, the pharmacokinetic parameters of DA-8159 with and without the intravenous administration of nitroglycerin became comparable. This was not due to the decrease in nitroglycerin's gastrointestinal absorption of DA-8159, but could have been due to changes in nitroglycerin's intestinal first-pass effect of DA-8159. Human studies are required to determine the administration time of DA-8159 when nitroglycerin is concomitantly taken.

Determination of nitroglycerin and its dinitrate metabolites in urine by gas chromatography-mass spectrometry as potential biomarkers for occupational exposure

This paper describes a method for the quantitative analysis of nitroglycerin and its dinitrate metabolites (1,2- and 1,3-glycerol dinitrate) in urine. After liquid-liquid extraction the analytes were separated and quantified using gas chromatography-mass spectrometry with negative ion chemical ionisation. The method can detect above 0.3 nmol/l for all analytes and is linear over the range of at least 0-44 nmol/l. The method was then used to determine metabolite levels in a subject using nitroglycerin therapeutically for the treatment of angina. Metabolites were stable in urine for at least 6 days at room temperature, approximately 4 degrees C and -20 degrees C.

Simultaneous determination of nitroglycerin and its dinitrate metabolites by capillary gas chromatography with electron-capture detection

A major problem in the analysis of nitroglycerin (propanetriol trinitrate, GTN) and its metabolites [propanetriol 1,2-dinitrate (1,2-GDN) and propanetriol 1,3-dinitrate (1,3-GDN)] has been the adsorption of the nitro compounds to glass apparatus during sample preparation or injection. In this paper we present a method determining GTN, 1,2-GDN and 1,3-GDN in plasma at low nanomolar level using capillary gas chromatography with electron-capture detection. The detection limits are about 0.2 nM in plasma. Adsorption of the nitro compounds to glassware is prevented by using triethylamine, giving a simple sample preparation and accurate results. Thus, the laborious and time-consuming silanization of the glassware is avoided.