Pharmacokinetics of penicillins in the blood of dogs administered the combination preparation, ampiox, internally]

The pharmacokinetics of penicillins in the blood of dogs treated with ampiox, a combination of ampicillin and oxacillin at a ratio of 1 : 1 was studied. The drug was administered orally in single or repeated doses of 25, 50 and 100 mg/kg. The maximum levels of ampicillin in the blood serum were observed 1 hour after a single administration of the drug. The therapeutic concentrations of the antibiotic were preserved for 6 hours, its value being depended on the dose used. The maximum concentration of oxacillin was detected 1 hour after the drug administration in various doses and it was preserved in the blood at the therapeutic levels for 3 hours. The dynamics of circulation of ampicillin and oxacillin administered separately did not differ from that established for the use of ampiox. The regularities of the pharmacokinetics of ampiox on its repeated use remained practically unchanged.     

Pharmacokinetics of triclabendazole in rabbits

1.Pharmacokinetic profiles of triclabendazole (TCBZ) following intravenous (i.v.) and oral administration of the drug in rabbits were carried out.2. In normal rabbits, TCBZ was metabolized rapidly to its sulphoxide (TCBZ-SO) and sulphone (TCBZ-SO₂) derivatives following administration, with undetectable concentrations of unchanged TCBZ in the plasma of the treated animals at any time (detection limit, 10 ng/ml).3. The disposition kinetics of this drug in rabbits can be described by a two-compartment open model.4. Mean peak concentrations in plasma of TCBZ-SO and TCBZ-SO₂ of 12.41 μg/ml and 9.5 μg/ml occurred 7.5 and 9.5 hr after oral administration, respectively.5. Both metabolites were eliminated slowly from plasma with elimination half-lives of 16.86 hr for the sulphoxide and 13 hr for the sulphone.6. The area under the plasma concentration versus time curve (AUC) was 240 mg hr/l for the sulphoxide, higher than that found for the sulphone, 185 g hr/l.     

Pharmacokinetics, biological effects, and distribution of (1-->3)-beta-D-glucan in blood and organs in rabbits

The pharmacokinetics, biological effects and distribution in blood and organs of 125I-labeled (1-->3)-beta-D-glucan purified from Candida albicans were analyzed in rabbits during the 24-h period following an intravenous administration.The intravascular half-life of (1-->3)-beta- D-glucan was 1.8 min in the low-dose group (9.3 mug/kg) and 1.4 min in the high-dose group (222 mug/kg), and the mean (+/-SD) total body clearance was 1.12 +/- 0.30 and 1.17 +/- 0.16 ml/min, respectively. The rabbits remained well and (1-->3)-beta-D-glucan failed to alter blood cell counts. Less than 3% of the (125)I-(1-->3)-beta-D-glucan was initially associated with the cellular compartment, and this value decreased further during the 2-h period following administration (P = 0.0001). Over 97% of (125)I-(1-->3)-beta-D-glucan was associated with cell-free plasma, and the majority in plasma appeared to be present in the unbound form (not associated with lipoproteins or plasma proteins). The liver contained more than 80% of the (125)I-(1-->3)-beta-D-glucan detected in the six major organs analyzed.     

Pharmacokinetics of the beta-carboline norharman in man.

In healthy subjects, pharmacokinetics were characterised using single oral and sublingual administrations of the beta-carboline norharman. For this purpose, norharman levels in blood plasma were measured up to 90-105 min after both routes of administration. Dose proportionality of three different single oral doses of norharman (7, 65 and 110 microg/kg) administered as 0.52 and 5 mg capsules was evaluated at 8 time points. Peak levels were attained at 30 min after the oral load of norharman. Mean relative availabilities determined by the area under the curve (AUC) procedure were 14.3 and 98.0 nmol.min/l after oral dosing of 7 and 65 microg/kg, respectively. AUC values in women were 3-4 times higher than in men. Sublingual dosing of 6.5 and 13 microg/kg norharman encapsulated in 5 mg of cyclodextrins resulted in a much higher mean AUC and a more rapid absorption. Mean AUC after sublingual administration of 6.5 microg/kg was 929.8 nmol.min/kg and plasma levels were maximal 10-15 min after norharman was given. Moreover, apparently no sex difference was found using this way of application. Norharman disappeared from the plasma with half-lifes of 25-35 min, irrespective of the route of administration. Even at the highest measured norharman levels of 53 nmol/l plasma, no behavioral effects were observed. In addition, the subjects did neither report any effects nor any side-effects during the experiment. This is the first study in which the kinetics of ingested norharman have been measured in humans.     

Pharmacokinetics of ibuprofen enantiomers in dogs

Inversion of inactive (R)-ibuprofen to active (S)-ibuprofen has been suggested to occur presystemically only. In order to investigate the site of inversion in dogs we administered both enantiomers either intravenously or intraduodenally (10 mg/kg) to adult, male beagle dogs (n = 3) in a crossover design. Plasma, urine, and bile were collected for up to 6 h and analyzed stereospecifically by HPLC, according to a previously published method. Pharmacokinetic parameters were calculated using a linear computer program. Absorption after intraduodenal administration occurred rapidly, resulting in maximum plasma concentrations 0.2 h after giving the enantiomer. Approximately 70% of the (R)-enantiomer (according to AUC) was inverted to the S-enantiomer independent of route of administration. No R-ibuprofen could be detected in plasma after (S)-ibuprofen administration. Mean residence time was found to be 2 to 3 times longer for (S)- than for (R)-ibuprofen. Total systemic clearance from plasma was twice as high for (R)- than for (S)-ibuprofen. There were no differences between plasma clearances after intravenous and intraduodenal administration. Between 8 and 17% of dose was recovered in bile [especially as free and conjugated (S)-ibuprofen] and 3-12% in urine [as (S)-ibuprofen, hydroxy- and carboxyibuprofen, free and conjugated forms]. Small amounts of (R)-ibuprofen were detected in bile after intraduodenal administration of (R)-ibuprofen only (1.8% of dose). In short, the unidirectional inversion of R-ibuprofen appears to occur systemically rather than presystemically in dogs.