Oral, intraperitoneal and intravenous pharmacokinetics of deramciclane and its N-desmethyl metabolite in the rat.

The pharmacokinetic properties of deramciclane fumarate (EGIS-3886), a new potential anxiolitic agent, and its N-desmethyl metabolite have been investigated in Wistar rats after 10 mgkg(-1) deramciclane fumarate was administered orally, intraperitoneally or intravenously. A highly sensitive, validated and optimized gas chromatographic method with nitrogen selective detection (GC-NPD) using a solid-phase extraction technique was used to determine plasma levels of the parent compound and its N-desmethyl metabolite. After oral administration the absorption of the parent compound was very fast (t(max) 0.5h). The maximum plasma concentration (C(max)) was detected at 44.9, > or =177.8 and > or =2643.0 ngmL(-1) after oral, intraperitoneal and intravenous administration of deramciclane, respectively. For the metabolite the respective Cmax values were 32.0, > or =25.4 and 51.0 ngmL(-1). The pharmacokinetic curves of both the parent compound and its metabolite showed enterohepatic recirculation for all administration routes. The biological half-life (tbeta 1/2) for deramciclane ranged from 3.42 to 5.44 h and for the N-desmethyl metabolite the range was 2.90-5.44 h, after administration of the drug by the three different routes. After intravenous administration AUC0-infinity, of deramciclane was 29.2- and 5.4-times higher than that observed after oral and intraperitoneal treatment, respectively. These AUC0-infinity ratios were only 2.1- and 1.5-times higher for the metabolite. The absolute bioavailability of deramciclane in rats was 3.42% after oral and 18.49% after intraperitoneal administration. The comparative pharmacokinetic study of deramciclane in rat after the different administration routes showed fast absorption. Furthermore, plasma levels were found to be administration route-dependent, low bioavailability of the parent compound indicated an extremely fast and strong first-pass metabolism. The apparent volume of distribution suggested strong tissue binding after administration of the drug by any of the three routes studied.

Pharmacokinetics of deramciclane in rabbits.

The pharmacokinetics of deramciclane (CAS 120444-78-8, EGIS-3886) was investigated in rabbits after i.v., p.o. and s.c. administration of 3 mg/kg 14C-phenyl-deramciclane. The plasma, concentration-time curves of total radioactivity, the parent compound (deramciclane) and its N-demethylated metabolite (EGIS-7056) were determined. The radioactivity level was measured by liquid scintillation technique while the concentration of the parent compound and its metabolite was determined by gas chromatography-mass spectrometry detection. The p.o. and i.v. studies were carried out on the same group of animals, while a separate group of rabbits was used for studying s.c. absorption. Deramciclane was readily absorbed after p.o. and s.c. treatment (tmax 1.0 to 1.4 h). The terminal elimination half-life (t1/2 beta) of the parent compound fell between 5.8 to 7.1 h, while that of the total radioactivity ranged from 21.6 and 26.0 h. The absolute bioavailability of deramciclane calculated from the AUC0-infinity values was found to be 43 and 60% after p.o. and s.c. treatment. The apparent volume of distribution (Vd) and the whole body clearance (Cl) of deramciclane after i.v. administration were 25.0 +/- 7.1 l/kg and 2.6 +/- 0.5 l/h/kg, respectively. The AUC0-infinity values of the parent compound varied between 4.6 and 7.9% of that of total radioactivity, suggesting that deramciclane was subjected to intensive metabolic conversion. The AUC0-infinity of N-desmethyl-deramciclane was 5.7%, compared to that of the parent compound after i.v. administration.

Pharmacokinetics of panomifene in healthy volunteers at phase I/a study.

Panomifene (PAN) /E/-1,2,-diphenyl-1-[4-[2-(2-hydroxyethylamino)-ethoxy]-phenyl]-3, 3,3-trifluoropropene is a new original Hungarian compound and is a tamoxifen (TMX) analog. In the phase I/a study presented here the human tolerance, pharmacokinetics and endocrine effects of a single oral dose of panomifene were evaluated in healthy, post-menopausal, female volunteers. As to the dose escalation, pharmacokinetic studies were carried out at doses of 24, 48 and 96 mg in two volunteers, and 120 mg in one volunteer. To find a suitable dose or dose range, for further evaluation of the drug detailed pharmacokinetics were performed at a selected dose level (24 mg) in 10 volunteers. The pharmacokinetic study showed considerable interindividual variability of the parameters, and only a medium correlation between dose and AUC (r=0.876). At the selected dose level (24 mg p.o.) the peak concentration of the plasma was 67.7 +/- 17.4 ng/ml (Cmax(meas)), the time to peak was 3.6 +/- 1.8 h (t[max(meas)]). The mean of the terminal half-life was 70.0 +/- 23.1 h (t(1/2beta)). The area under the plasma concentration time curve (AUC) calculated by the kinetic equation (AUCcalc) was 4814 +/- 1172 and by the trapezoidal rule (AUCtrap) was 4612 +/- 1357 (ng/ml) h.

Determination of panomifene in human plasma by high-performance liquid chromatography.

An ion-pair HPLC method was developed for the determination of the antiestrogenic drug panomifene, (E)-1,2-diphenyl-1-(4-[2-(2-hydroxyethylamino)ethoxy]phenyl)-3,3,3 - trifluoropropene, in human plasma. Tamoxifen, 20 ng in 1 ml of plasma, was used as an internal standard. The compounds were isolated from plasma by liquid-solid extraction. Fluorescence detection was achieved by on-line photochemical conversion of the compounds into highly fluorescent phenanthrene derivatives. The sensitivity of the method was 1 ng/ml. The within-day and between-day precision, linearity, extraction recovery and stability of panomifene in plasma and in deproteinized plasma were determined for validation of the method. The method is suitable for measuring plasma levels of panomifene and tamoxifen and for pharmacokinetic studies.