Biomedical subjects

J N Jedema

Publications and source records attributed to J N Jedema.

3 recordsLinked to original sources

PubMed1991

Minor effect of multiple dose omeprazole on the pharmacokinetics of digoxin after a single oral dose.

1. The influence of multiple dose administration of omeprazole on the pharmacokinetics of oral digoxin was studied in 10 healthy male volunteers. 2. In a randomized two-way crossover design a single dose of 1 mg digoxin was administered either alone (control) or on day 8 of an 11 day course of omeprazole 20 mg once daily. 3. Plasma digoxin concentrations were measured over 96 h after digoxin administration with a [125I]-r.i.a. method. 4. On average, Cmax and AUC values for digoxin were approximately 10% higher and tmax tended to be shorter during the administration of omeprazole, while the elimination rate constant was unaffected. 5. The increase in AUC(0,96 h) was statistically significant (P less than 0.05), but within the accepted range for bioequivalence. In two subjects the increase was approximately 30%. 6. It is concluded that co-treatment with omeprazole causes a minor increase in the absorption of oral digoxin. The magnitude of this effect is not considered to be clinically relevant for the majority of patients.

Administration, Oral↗

PubMed1988

No effect of influenza vaccination on theophylline pharmacokinetics as studied by ultraviolet spectrophotometry, HPLC, and EMIT assay methods.

The effect of influenza vaccination on steady-state pharmacokinetics of theophylline was studied in six healthy young adults by comparing pharmacokinetic parameters found on days 4 and 5 during a 5-day course of theophylline alone with those obtained after influenza vaccination on day 4 of a second study phase. Theophylline plasma concentrations were measured by means of high-pressure liquid chromatography (HPLC) analysis and, in part, with a manual ultraviolet spectrophotometric method and with an EMIT assay. On the fourth and fifth days of each of the two periods of drug administration, theophylline plasma concentration-time curves were evaluated, and the following pharmacokinetic parameters were compared: trough plasma concentration (cmin), peak plasma concentration (cmax), time to peak (tmax), and the area under the curve during a dosing interval (AUC). None of these pharmacokinetic parameters of theophylline before and after vaccination were found to be significantly different with any of the analytical methods.

Adult↗

PubMed1987

Single dose bioavailability of two different digoxin tablets.

In a single dose bioequivalence study in 10 healthy young adults the absorption profiles and bioavailability of two digoxin containing tablets (A = digoxin-Pharbita 0.25 mg and reference drug B) were compared and related to the in vitro dissolution rate of both tablets. Two tablets of each product (= 0.50 mg of digoxin) were taken at random on an empty stomach; two weeks elapsed between the two treatments. Frequent blood sampling was performed up to 24 h after intake of the dose. Digoxin plasma concentrations were measured by means of radioimmunoassay. No significant differences (p greater than 0.05) were found in the mean values of the peak plasma concentration (cmax), time to peak (tmax) and area under the plasma concentration versus time curve for the period of 0-10 h after drug intake (AUC0-10), although in most subjects the absorption process after intake of product A was slightly faster, with slightly higher peak. This might be related to a slightly faster release of digoxin from the product A dosage form, as was seen from the dissolution test data. The relative bioavailability of product A as compared to product B, accounted for 97.7 +/- 28.7% (mean +/- S.D.). These results indicate, that both products can be considered as being bioequivalent.

Adult↗