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Biomedical subjects

D B Jack

Publications and source records attributed to D B Jack.

At least 73 records · Page 4Linked to original sources
PubMed1981

The influence of food on the absorption of diclofenac as determined by the urinary excretion of the unchanged drug and its major metabolites during chronic administration.

Six healthy subjects took diclofenac as an enteric-coated preparation twice daily for 17 days under the following conditions: (i) fasting, (ii) 15 min before a meal, and (iii) immediately after a meal. Urine specimens were collected on two separate days of each regimen and diclofenac and its total monohydroxylated metabolites measured. Statistical analysis of the excretion of diclofenac and its metabolites showed that, during chronic administration, absorption was not significantly influenced by dosing before or after food. The absorption pattern after both these modes of administration was comparable to that obtained under fasting conditions.

Absorption↗
PubMed1981

The effect of age on the pharmacokinetics of metoprolol and its metabolites.

1 Plasma concentrations of metoprolol and a pharmacologically active metabolite, H119/66, have been measured in young and elderly volunteers after a single dose of 100 mg metoprolol tartrate and after repeated administrated over a period of 1 week. Whilst concentrations of metoprolol are similar in each group, concentrations of H119/66 are approximately twice as high in the elderly. 2 Concentrations of unchanged metoprolol and of the major, but pharmacologically inactive, metabolite, H117/04, together with the two active metabolites of metoprolol have been determined in urine. Only the excretion of metoprolol was diminished in the elderly. 3 Areas under the plasma concentration curve for metoprolol after repeated administration are greater than would be predicted from single dose data, and possible explanations for this are discussed. Concentrations of the pharmacologically active metabolite, H119/66, remain unaltered during chronic dosing of metoprolol. 4 This study has shown that the effect of age on the pharmacokinetics of metoprolol and its metabolites is less pronounced than that observed for other drugs.

Adolescent↗
PubMed1981

Pharmacokinetics of cephradine given intravenously with and without probenecid.

1 In the light of questions raised by an earlier oral study (Welling, Dean, Selen, Kendall & Wise, 1979) the influence of probenecid on the pharmacokinetics of intravenously administered cephradine has been investigated. 2 Intravenous administration of cephradine resulted in a bi-exponential curve and the level of antibiotic after 15 min was significantly greater when subjects received probenecid than when they did not. The influence of probenecid on urinary excretion of cephradine was similar to that observed previously. 3 The increase in serum of cephradine due to probenecid could be accounted for by the decrease in the elimination rate of the antibiotic. These results are discussed in the light of other observations.

Adult↗
PubMed1980

A study of the effect of aspirin on the pharmacokinetics of oral and intravenous diclofenac sodium.

Previous studies have shown that aspirin interacts with orally administered diclofenac sodium, causing reduced peak concentrations, lower levels and decreased areas under curves. In this study, diclofenac sodium was administered orally and intravenously with and without aspirin, to 6 healthy female volunteers. After intravenous dosing both plasma levels and areas under curves were significantly reduced although none of the rate constants was affected. The volume of distribution of diclofenac was increased as was the plasma clearance. Oral administration with aspirin also resulted in lower plasma levels, particularly peak levels, and areas under curves. Comparison of AUC's for both modes of administration with and without aspirin suggested that lower levels after oral administration were not due to impaired absorption. These observations are best explained by decreased protein binding and increased biliary excretion of diclofenac in the presence of salicylate.

Administration, Oral↗
PubMed1975

The determination of hydralazine in plasma by gas-liquid chromatography.

A description is given of a gas chromatographic method for the determination of hydralazine in plasma. On treatment with nitrous acid, hydralazine is converted into tetrazolo[1,5-a]phthalazine, a stable compound that can be extracted from biological material with organic solvent and determined quantitiatively by gas-liquid chromatography. The 4-methyl analogue of hydralazine serves as internal standard for derivatization, extraction and gas chromatography. The sensitivity (10 ng per ml of plasma) is sufficient to monitor plasma levels in man after administration of single oral doses of 50 mg of Apresoline¿. The known metabolites do not interfere.

Chromatography, Gas↗
PubMed1975

[Anticoagulant efficacy of Sintrom and blood concentration of Ludiomil on simultaneous administration of the two preparations].

As long-term anticoagulant therapy with coumarin derivates like Sintrom becomes more and more important the question arises whether there is an interaction with a new drug like Ludiomil. An open, noncomparative trial was carried out with 20 patients receiving Sintrom (overall mean :3.0 mg/d, range :0 to 10 mg/d) for a period of 4 weeks, and in addition, during the second and third week Ludiomil (50 mg t. i. d.) orally. As a measurement of the efficacy of the antiocoagulant therapy, the correlation coefficients between the doses of Sintrom and the prothrombin value of the nex day were calculated for each patient and each week separately. An analysis of variance did not show any statistically significant difference between the correlation coefficients of the weeks with and without Ludiomil therapy, i.e. there is no change in the efficacy of the anticoagulant therapy. During the Ludiomil therapy the control of the anticoagulant therapy was slightly better, i.e. the fluctuations of the prothrombin values less, but statistically these differences were not significant. The plasma levels of Ludiomil in these patients were similar to thse found previously in both depressed and healthy volunteers.

Acenocoumarol↗