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Biomedical subjects

G Franke

Publications and source records attributed to G Franke.

At least 73 records · Page 4Linked to original sources
PubMed1989

Kinetics of antipyrine and sulfamethazine in patients recovered from dihydralazine-hepatitis.

Pharmacokinetic studies with sulfamethazine (500 mg) and antipyrine (15 mg/kg) were performed in 27 hypertonic patients (16 females, 11 males, 37-78 years) who had recovered from a dihydralazine-induced hepatitis, and 21 patients with essential hypertension (13 females, 8 males, 18-74 years) treated with antihypertonics excluding dihydralazine. 20 patients of the hepatitis group (74%) and 12 patients of the control group (57%) were slow acetylators. With regard to the pharmacokinetic parameters no differences were found in both slow and rapid acetylators between the sulfamethazine group and the antipyrine group.

Acetylation↗
PubMed1988

N-acetylator phenotypes in hyperthyroidism.

Acetylator phenotypes were determined with sulfamethazine in 114 healthy volunteers, 87 patients with immunogenic hyperthyroidism (Graves' disease) and 38 patients with disseminated thyroid autonomies. About 90% of the patients were females. No significant differences of acetylator phenotypes were observed between female volunteers and hyperthyreotic patients younger than 50 years. The proportion of slow acetylators was higher in older patients. Early and late relapses did not depend on acetylator status.

Acetylation↗
PubMed1988

[The pharmacokinetics of 2-methyl-4-nitroimidazole-1-ethanol (isometronidazole) in man].

2 and 4 g isometronidazole, respectively, were administered to two groups of 6 healthy male volunteers (21-29 years, 62-93 kg). The unchanged compound and its nitro group containing metabolites were measured by HPLC and polarography. Isometronidazole was absorbed rapidly, distributed slowly into peripheral compartments and eliminated with half lives of about 12 h. It was not bound to plasma proteins. On an average 70% (2 g) and 80% (4 g), respectively, were excreted into urine within 48 h both unchanged and in form of at least two more polar and/or water soluble metabolites. Distribution and excretion of isometronidazole were not proportional to dose.

Adult↗
PubMed1987

[Pharmacokinetics of dihydralazine following intravenous administration in laboratory animals].

Comparative pharmacokinetic studies with high i.v. doses of dihydralazine (1, 5 and 7.5 mg/kg-1, respectively) were performed in rats, rabbits, and dogs. 1 was distributed in rabbits and dogs in two phases with half lives of 0.25-0.4 min and 1.0-2.0 min. The terminal slope was species dependent. The relative clearance values decreased in the order rabbit, rat, dog. High tissue concentrations were observed in rabbits and dogs in parenchymatous organs and endothelium (aorta). Skeletal and heart muscles belonged to the central compartment. The biliary excretion was low in rabbits. Dogs accumulated the drug in bile (bile/serum-ratios = 19-390). Maximally 5% of the given dose were excreted in rabbits with the 12-h-urine.

Animals↗
PubMed1987

Interactions of dihydralazine with furosemide in hypertonic patients.

In 9 hypertensive patients stage II we studied whether dihydralazine, which is known to increase the renal blood flow, influences the elimination of furosemide (40 mg i.v.) when given additionally over a period of 2 weeks (75 mg daily). The results were compared with data from 9 healthy volunteers. The most important alterations in hypertonics were significantly increased half-lives (28.0 +/- 3.7 and 35.1 +/- 5.7 min), distribution coefficients (0.105 +/- 0.017 and 0.132 +/- 0.028 ml/g) and unchanged plasma clearances (2.62 +/- 0.33 and 2.59 +/- 0.27 ml min-1 X kg-1). Pretreatment with dihydralazine resulted in normalization of distribution coefficients (0.134 +/- 0.027 and 0.102 +/- 0.020 ml/g), decrease in plasma clearance (2.55 +/- 0.29 and 2.08 +/- 0.23 ml min-1 X kg-1) without alterations in half-lives (36.3 +/- 6.0 and 34.2 +/- 7.0 min). The authors conclude that the effects after dihydralazine co-medication are only distribution mediated.

Adult↗
PubMed1986

Studies on the kinetics and distribution of dihydralazine in pregnancy.

Plasma kinetics of dihydralazine (50 mg p.o.) was studied in 11 women in late pregnancy. The distribution pattern between maternal and umbilical plasma was investigated in 12 patients who received 75-100 mg dihydralazine per day. In one patient amniotic fluid concentration and in another breast milk levels could be evaluated twice. Plasma concentrations of dihydralazine were very low. Continuous plasma level curves could be estimated in only four of the examined patients. In every case dihydralazine concentrations were higher in umbilical blood than in maternal plasma. Concentrations found in breast milk were clinically negligible.

Administration, Oral↗
PubMed1985

The influence of the acetylator phenotype for the clinical use of dihydralazine.

Dihydralazine is a substrate of the human N-acetyltransferase. Therefore the acetylator phenotype could influence the pharmacodynamic response of dihydralazine and/or side effects of this drug. In this study it could be shown that: among patients with dihydralazine incompatibility slow acetylators preponderated; the risk of early side effects was higher in females than in males; and the ratio of fast/slow acetylators was higher in dihydralazine treated patients than in patients treated with other antihypertensives. Dihydralazine should be given very cautiously to female hypertonic patients that are slow acetylators.

Acetylation↗
PubMed1985

Bioavailability studies of calcium dobesilate--a case of flip-flop kinetics.

Absolute and relative bioavailability of two commercial calcium dobesilate tablets were evaluated in ten healthy volunteers in a cross-over trial using a newly developed HPLC detection method. Both tablet forms were absorbed completely but very slowly thus leading to a flip-flop kinetics. It could be shown that AUC values derived from flip-flop models were comparable with those of normal i. v. kinetics.

Absorption↗
PubMed1985

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

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.

Acetylation↗
PubMed1984

[Effect of thyroid hormones on noradrenaline-stimulated lipolysis in obesity].

11 extremely adipose patients were over 4 days loaded with a noradrenalin infusion of 0.1 microgram/kg body weight/minute over 60 minutes before and after a daily application of 200 micrograms tri-iodothyronine. The determination of the free fatty acids and of glycerin resulted in a significant elevation basally as well as after stimulation with noradrenalin. Thus the lipolytic influence of the thyroid hormones is confirmed under in-vivo-conditions. The possible mechanisms of lipolysis in the fatty tissue are discussed on the basis of literature.

Adolescent↗
PubMed1983

Disposition kinetics of metronidazole in children.

The pharmacokinetics of metronidazole was studied in 20 paediatric patients aged 6 weeks and 4 to 14 years, who had trichomonal vaginitis or an anaerobic bacterial infection. The dosage of metronidazole was about 10 or 20 mg/kg b.i.d. orally. The serum concentrations found in children and the corresponding calculated kinetic parameters were similar to those in adults after intake of an equal, weight-related dose. Metronidazole shows rapid diffusion into the saliva with a concentration ratio of about 1.0. This can provide the basis for an efficient non-invasive method of drug monitoring.

Adolescent↗
PubMed1983

[Phenytoin kinetics in toxic serum levels].

After discontinuing Phenytoin, the elimination kinetics was determined in 12 patients with toxic serum levels of more than 30 micrograms/ml. The half-lives of the elimination were between 72 and 122 h (97 h). The Michaelis constant amounted to 16,3 +/- 5,6 micrograms/ml and per day and the maximum rate of metabolism 9,9 +/- 1,1 microgram/ml and per day. The elimination half-lives was dependent on the concentration: the higher the serum concentration the longer the half-live. A method applicable in general practice for determining the course of the serum level with initial values of more than 30 micrograms/ml was described.

Adolescent↗
PubMed1982

[The behavior of the thyrotropin-releasing hormone test in fasting with and without triiodothyronine administration].

It is reported on the performance of the 400 microgram TRH/TSH test in adipose persons in the course of a zero diet and on the effects of an application of 50 micrograms tri-iodothyronine during 7 days on the TRH/TSH test on the same conditions. During total fasting the basic and TRH-stimulating TSH-level shows a slight tendency of decrease, but scarcely significant changes. After application of 50 micrograms tri-iodothyronine an unequivocal suppression of the TSH-concentration in the serum is to be recognized. By these results and with the help of literary data by means of the most sensitive test of the diagnostics of hypothyroidism a general hypofunction of the pancreas could be excluded, as it was supposed in the low T3 syndrome. But tri-iodothyronine deficiency in some tissues is still discussed at present.

Adolescent↗