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Biomedical subjects

D Tremblay

Publications and source records attributed to D Tremblay.

At least 37 records · Page 2Linked to original sources
PubMed1990

Pharmacokinetics of cefpodoxime in young and elderly volunteers after single doses.

Three pharmacokinetic studies involving single oral doses of cefpodoxime proxetil in healthy volunteers are reported. The first study was to determine the absolute bioavailability of cefpodoxime, the second was to study the relationship between the oral dose of cefpodoxime proxetil and pharmacokinetic parameters of cefpodoxime, and the third was to compare the pharmacokinetics of cefpodoxime in healthy young and elderly volunteers. Half the dose of cefpodoxime orally administered as cefpodoxime proxetil in tablet form reaches the systemic circulation, while 80% of the cefpodoxime absorbed is excreted unchanged in urine. The volume of distribution is large (32.3 l). The pharmacokinetics of cefpodoxime were linear in young and elderly subjects after 100 and 200 mg oral doses, which are those used therapeutically. The Cmax was about 1.4 mg/l (after 100 mg) and 2.6 mg/l (after 200 mg). Deviation from linearity appeared at 400 mg and the effect was confirmed at 800 mg. The differences between young and elderly subjects were negligible, with the exception of the half-life which increased by only 14%, from 2.67 to 3 h. Dosage adjustment is therefore not necessary in the elderly.

Administration, Oral↗
PubMed1990

Multiple dose pharmacokinetics of cefpodoxime in young adult and elderly patients.

Multiple dose pharmacokinetics of a new third-generation cephalosporin, cefpodoxime, were evaluated in adults (15, 18-60 years) and elderly adults (10, greater than or equal to 70 years), all out-patients suffering from acute lower respiratory tract infection. A dose of 200 mg cefpodoxime proxetil (expressed in mg cefpodoxime) was administered 12-hourly for seven to ten days and timed blood samples were evaluated on days 0, 3, 5, 6/7 and on the last day of treatment. Results showed that the pharmacokinetics in adult and elderly patients were comparable with those of healthy volunteers and with each other, with the exception of one elderly patient with severe renal impairment. Dosage adjustment of cefpodoxime proxetil does not therefore appear to be necessary in the elderly unless there is evidence of severe renal insufficiency.

Adolescent↗
PubMed1989

Inhibition of carbonic anhydrases in type I muscle fibers influences contractility.

We tested the effects of inhibiting the carbonic anhydrase activity of rat soleus and extensor digitorum longus muscles on the isometric contractile properties and the resistance to fatigue. SOL and EDL muscles from female rats were incubated in vitro in the presence of methazolamide, a specific inhibitor of carbonic anhydrase, before determining their contractile properties. Methazolamide had no effects on the contractile properties of the soleus muscle (10(-5) or 10(-3) M) and extensor digitorum longus (10(-3) M), except for the half-relaxation time of the soleus muscle which increased significantly. Values for half-relaxation time were significantly increased with both concentrations of the inhibitor. Muscles were then submitted to a fatigue protocol lasting 30 min. During the fatigue test, no significant difference was observed between control and 10(-5) M methazolamide soleus muscles. In presence of 10(-3) M methazolamide however, the soleus muscle showed a significantly increased resistance to fatigue compared with control preparations. No significant effect was observed with the extensor digitorum longus muscle exposed to 10(-3) M methazolamide. Results are discussed in terms of the presence of two different isoforms of carbonic anhydrase that may be associated with calcium uptake and energy metabolic processes, respectively.

Animals↗
PubMed1988

Pharmacokinetics of Anandron in patients with advanced carcinoma of the prostate.

The pharmacokinetics of total radioactivity and unchanged drug were studied in patients receiving Anandron (Nilutamide, RU 23908) after a single dose of [14C] Anandron and after q12 h dosings of unlabelled drug for 2-7 weeks. The results indicate that the radioactivity in plasma consists of unchanged drug and metabolites. The plasma decay of Anandron after the absorption phase was biexponential in all patients, with the terminal phase half-life ranging from 23.3-87.2 h. The plasma decay of total radioactivity after the absorption phase was biexponential in 3/12 and monoexponential in 9/12 patients. The calculated terminal phase half-lives for total radioactivity after [14C] Anandron were 34.5-137.3 h. The AUC0-infinity of the unchanged drug in plasma represented 23%-38% of the AUC0-infinity of total radioactivity. Urinary radioactivity consisted primarily of metabolites, the majority of which were chloroform-nonextractable. Urinary excretion of radioactivity at 120 h ranged from 49%-78% of the administered dose; the unchanged Anandron (at 72 h) was 0.6%-1.3% of the dose. In three patients studied, the fecal excretion of Anandron was 1.4%-7.0%. Steady-state plasma levels (4.4-8.5 micrograms/ml) were attained within approximately 2 weeks from the initiation of twice daily dosing of Anandron. When the plasma pharmacokinetics of radioactivity and unchanged drug after the first single dose were compared with that during steady state, AUC0-12h of unchanged Anandron during steady state was significantly higher than the AUC0-infinity after the first single dose, suggesting that the plasma clearance of Anandron is lowered upon chronic administration of the drug, assuming that the bioavailability is constant.

Aged↗
PubMed1987

A study of the interaction of roxithromycin with theophylline and carbamazepine.

There have been reports of an interaction when theophylline and macrolides are given together, and also when carbamazepine is given with macrolides. We compared the kinetics of theophylline and carbamazepine, given alone and then in combination with roxithromycin. Roxithromycin had little effect on the pharmacokinetics of theophylline and none on carbamazepine, and roxithromycin can be given with either of the drugs without any need to alter the dose.

Adolescent↗
PubMed1986

Pharmacokinetics of ofloxacin and theophylline alone and in combination.

The pharmacokinetic interactions of ofloxacin (2 X 200 mg) and theophylline (3 X 200 mg) were investigated in 12 healthy volunteers over a period of two weeks. In the first week, theophylline was given over five days to reach a steady state. In the second week, the combination of theophylline and ofloxacin was applied. Cmax, tmax, AUC0-8, the serum elimination constant and serum half-life of theophylline were not changed when theophylline was given alone or in combination with ofloxacin. The kinetic parameters of ofloxacin were in accordance with data from the literature.

Adolescent↗
PubMed1985

[RU 28965, a new semi-synthetic macrolide. Bioavailability and pharmacokinetic profile after oral administration].

The plasma concentration of RU 28965, a new semisynthetic macrolide, was monitored for 24 h after single 400 mg oral doses in 8 healthy volunteers. Four tablet formulations were compared in a 4 X 4 latin square design, to assess the influence of micronization and enteric coating on bioavailability. Plasma samples were assayed for unchanged RU 28965 using HPLC. Extent of absorption was equivalent for all four formulations. Micronization did not significantly affect absorption characteristics, while enteric coating resulted in slower absorption. In the second part of the study, plasma concentration was monitored for 72 h after a single oral dose of two 150 mg non-coated, non-micronized tablets in another group of 12 subjects. The following pharmacokinetic parameters were found (m +/- sem) : cmax = 11.8 +/- 0.3 microgram.ml-1, AUC = 132 +/- 17 microgram.ml-1.h, t 1/2 = 12 +/- 0.5 h.

Absorption↗
PubMed1983

Pharmacokinetics in man of a new antiarrhythmic drug, cibenzoline.

The kinetics of cibenzoline (UP 339.01), a new antiarrhythmic drug, was studied after i.v. and oral administration to 5 healthy subjects. Cibenzoline levels in plasma and urine cibenzoline were measured by a GLC method. After i.v. administration, the total clearance was 826 ml . min-1. The fraction of cibenzoline excreted unchanged in the urine was 0.602 and it was correlated with the creatinine clearance. After i.v. and oral administration, the renal clearances were 499 ml . min-1 and 439 ml . min-1, and the half-lives were 4 h 01 min and 3 h 24 min, respectively. The differences were not significant. Availability by the oral route was 0.92, the maximum plasma concentration being observed at 1 h 36 min. The results were compared with those for other antiarrhythmic drugs.

Administration, Oral↗
PubMed1983

The pharmacokinetics and availability of niflumic acid in humans.

The pharmacokinetic parameters and relative availability of niflumic acid in two different pharmaceutical preparations were studied in 12 subjects after a single oral administration. Total plasma clearance averaged 45 ml/min, and the half-life of elimination approximately 2 h, giving a distribution volume of 0.12 l/kg on the average. The values of these pharmacokinetic parameters were in agreement with the general characteristics of this type of substance, a weak acid strongly bound to plasma proteins. Comparison of the systemic availability of the two oral forms showed no difference; they were probably close to 100%.

Absorption↗