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H J Huber

Publications and source records attributed to H J Huber.

8 recordsLinked to original sources
PubMed1992

Pharmacokinetics of nilvadipine.

Nilvadipine is absorbed rapidly and completely and its absolute bioavailability is about 14-19% because of its high first-pass metabolism. Maximum plasma levels and the extent of bioavailability increase proportionally with the dose. Nilvadipine is mainly excreted via the kidney as inactive metabolites. Slow tissue redistribution is probably the reason for the terminal elimination half-life of 15-20 h. There was a good correlation between the estimated tissue concentration and the reduction in blood pressure in patients. The use of the sustained-release pellet formulation can prevent plasma level peaks and thereby lessen the typical side effects of dihydropyridine calcium antagonists. The pharmacokinetics of nilvadipine were not affected by impaired renal function, and although the bioavailability was increased in liver cirrhosis, there was no accumulation after repeated doses. There was no effect on plasma digoxin levels. The plasma concentration of nilvadipine can be affected by either activation or inhibition of the cytochrome P450 system. The use of a sustained-release once-a-day formulation to lower the peaks in plasma levels along with nilvadipine's long terminal half-life means that this well-tolerated pharmaceutical formulation can be employed in clinical trials for the treatment of hypertension and expected to work over 24 h.

Absorption↗
PubMed1992

24-hour blood pressure control after single daily doses of nivaldipine in patients with essential hypertension.

In an open monocentric phase II study, 20 inpatients with hypertension were treated with a single daily dose of nilvadipine for 3 weeks after a 1-week placebo washout phase. The initial dose in all patients was 8 mg/day p.o.; this was doubled to 16 mg once daily if an adequate blood pressure reduction was not achieved after 10 days on 8 mg. The objective of the study was to investigate the effect of this new calcium antagonist on the blood pressure in hypertensive patients. This was done by means of a 24-h blood pressure profile (with measurements at 0.5, 1, 2, 4, 8, 12, and 24 h after administration), and over the complete course of the treatment period (blood pressure measurements each day just before the medication was given). In addition, by determination of the nilvadipine plasma levels on the first, tenth, and last medication day, a possible concentration-efficacy relationship was to be ascertained between plasma concentration of nilvadipine and the observed blood pressure-lowering effect of the drug. Adequate blood pressure reductions were achieved with nilvadipine 8 mg once daily in 13 patients; 7 required a doubling of the dosage to 16 mg/day. Already on the first day of therapy, both the systolic and diastolic blood pressures were significantly reduced compared to those in the placebo phase (p < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

[Ambulatory surgery].

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Ambulatory Surgical Procedures↗
PubMed1981

[Bioavailability of theophylline in a new oral sustained-release preparation (author's transl)].

On the basis of biopharmaceutic-pharmacokinetic and galenic aspects a new sustained-release preparation of theophylline according to the "divided-dose" principle was developed. The technological procedure used allows a reproducible manufacture of a stable product with narrow limits of pharmaceutical quality. The bioavailability of the sustained-release pellets in a dose corresponding to 350 mg active principle is examined in comparison to an aqueous solution or retard-tablet formulation on the marked (containing 260 mg drug/dose), respectively, after single or multiple dose administration to 7 healthy volunteers. The relative bioavailability of the new formulation is about 100%. During chronic application the controlled drug delivery from the sustained-release pellets warrants only slight fluctuations of plasma levels by avoiding peak concentrations. Formulations with a dosage of 200, 350 or 500 mg, respectively, allow adaptation of continuous plasma levels in the therapeutic range between 5--20 micrograms/ml according to the therapeutic necessities of a patient.

Adult↗
PubMedDate not supplied

Pharmacological activities of droloxifene isomers.

Droloxifene (DROL) is a new antiestrogen which is used for the treatment of endocrine-responsive breast cancer in humans. As Droloxifene exists in a Z- and E-isomer, we investigated the main pharmacological properties of both isomers. For both compounds the following tests were conducted: affinity for the estrogen receptor (ER); effect on the growth of rat uteri; influence on the growth of the ER + human breast cancer cell line ZR-75; and isomer interconversion in vitro. DROL-(Z) had binding affinity to the cytosolic ER approximately ten times lower than that of DROL-(E). Furthermore, the estrogenic effect of DROL-(Z) in the rat uterus is weak and there is no antiestrogenic activity. The lack of antiestrogenic activity of DROL-(Z) in contrast to DROL-(E) could also be shown in the human breast cancer cells ZR-75. Thus DROL-(Z) is, as far as investigated, without antiestrogenic and estrogenic activities. Of note is the stability of both DROL-isomers. There is no interconversion or metabolism of the parent compounds DROL-(E) and DROL-(Z) in vitro.

Animals↗