ABSTRACT
In the present study the pharmacokinetics of BRLP-42--a new antiischaemic agent--was investigated in dogs and rats. Plasma concentrations were measured by HPLC. After intravenous application the curves can be characterized by a two-compartment open pharmacokinetic model. The central volume of distribution (Vcentr.) is large (1.07 +/- 0.14 l/kg in dogs and 2.74 l/kg in rats), the first elimination half-life (t1/2 alpha) is 5.47 +/- 1.67 min in dogs and 13.7 min in rats. These facts indicate rapid and large tissue distribution. The excretion and/or metabolic elimination of BRLP-42 resulted in short second elimination half-life (t1/2 beta = 41.45 +/- 2.34 min in dogs and 43.8 min in rats). After oral application high individual variability can be seen. This fact may be due to the different rate and/or extent of absorption process. The plasma level curves can be characterized by a one-compartment open pharmacokinetic model. The absorption seems to conceal the distribution phase of the kinetic curve. The absorption half-life was short (t1/2a = 17.36 +/- 5.90 min in dogs and 2.7 min in rats). The bioavailability was 40 +/- 8% in dogs and 28% in rats. The elimination half-life (t1/2e = 28.77 +/- 0.88 min in dogs and 30.1 min in rats) is connected dominantly with metabolic elimination and/or excretion of BRLP-42. In the cases of intravenous as well as oral administrations the plasma concentrations decreased under the limit of quantitation by 4-6 hours in dogs and 4 hours in rats after treatments.
Subject(s)
Ischemia/drug therapy , Piperazines/pharmacokinetics , Pyridines/pharmacokinetics , Administration, Oral , Animals , Chromatography, High Pressure Liquid , Dogs , Injections, Intravenous , Male , Piperazines/blood , Pyridines/blood , Rats , Rats, Inbred StrainsABSTRACT
Pharmacokinetic properties of active substance of Hevizos ointment (Epervudine) were studied in rats after intravenous, oral and dermal applications. The animals received 10 mg/kg of Epervudine intravenously and orally. For checking of dermal absorption 220 mg of ointment (containing 0.8% of Epervudine) was applied. An HPLC method was developed for determination of Epervudine concentrations in serum. The method meets the requirements of precision and accuracy of the kinetic measurements (i.e. CV% is less than 20%) within the concentration range of 50-10,000 ng/ml. The mean serum concentration-time curve after i.v. administration can be characterized by a two-compartment open pharmacokinetic model. The first and second elimination half-lives (t1/2 alpha and t1/2 beta) are 0.14 and 0.31 hours, respectively. These values indicate fast distribution and elimination of compound studied. In the case of oral administration the absorption process conceals the fast distribution, so the mean serum concentration-time curve can be characterized by a one-compartment open pharmacokinetic model. The absorption of Epervudine starts practically prompt. The absorption half-life (t1/2a) is 0.11 hours. Highest serum concentrations were measured from 20 to 90 minutes after treatment. The elimination half-life (t1/2e) is 1.53 hours. The ratio of areas under serum level curves following oral and intravenous administration proves a good bioavailability (90%) of Epervudine. After dermal application Epervudine does not absorb.
