[Quantitative determination and kinetics of dihydralazine in hypertension patients].

Abstract

For the quantitative determination of dihydralazine (1) a derivative with acetylacetone in biological material was formed at pH = 4.9, extracted with n-hexane, and measured gaschromatographically with N-P-FID. Acid labile 1 was hydrolyzed with HCl (1 mol/l) for 24 h. The detection limit was 25 nmol/l plasma. Kinetic studies were performed in 16 patients with essential hypertension under steady-state conditions after the oral application of 50 mg 1. The acetylator phenotype was determined with sulfamethazine. Complete dihydralazine plasma level-time courses were found in only 5 cases. The concentrations were below the detection limit in 4 patients for the whole period. Only single values could be registered in the remaining patients. Maximal plasma levels of the free (58-314 nmol/l) and acid labile 1 (147-367 nmol/l) were reached 20-40 min after the application. The elimination half life was 23-47 min for the free 1, 55-92 min for the acid labile 1. Less than 0.5% of the applied drug were excreted into the 24 h urine in its free form, about 0.4% as acid labile derivatives. No correlation could be found between the acetylator phenotype of the patients and the kinetic behaviour of the drug. Preliminary studies concerning the biliary excretion of 1 after i. m. application in two patients with T-drain showed an accumulation of the free compound with bile/plasma ratios up to 7.4.

• Authors: W Siegmund, M Zschiesche, R Kallwellis, G Franke, T Schneider, U Sill, A Scherber, H Hüller
• Journal: Die Pharmazie (Pharmazie) Vol. 40 Issue 11 Pg. 779-81 (Nov 1985) ISSN: 0031-7144 [Print] Germany
• Vernacular Title: Quantitative Bestimmung und Kinetik von Dihydralazin bei Hypertoniepatienten.
• PMID: 4095128 (Publication Type: English Abstract, Journal Article)

Chemical References

• Hydralazine
• Dihydralazine

Topics

• Acetylation
• Adult
• Aged
• Bile (metabolism)
• Dihydralazine (metabolism)
• Female
• Humans
• Hydralazine (analogs & derivatives)
• Hypertension (metabolism)
• Kinetics
• Male
• Middle Aged
• Phenotype