28-day oral toxicity study with soft corticosteroid BNP-166 in rats and dogs, followed by a 14-day recovery period.

The aim of the present study was to evaluate the soft corticosteroid BNP-166 in rats and dogs treated orally with 0.2, 2.0, and 20.0 mg/kg for 28 days and the reversibility of any abnormalities during a 14-day post-dosing period. The test substance, BNP-166, was well tolerated during the 28-day treatment period. The observed changes were all characteristic for the pharmacological actions of a glucocorticoid. Treatment related changes occurred in the adrenals and thymus, and, to a lesser extent, in the lymph nodes, spleen and liver. There were no statistically significant reductions in the cortisol levels of all groups in the 0.2 and 2 mg/kg treatments. Significant reductions were observed in the high-dose group (20 mg/kg), but levels returned to normal by the end of the 14-day recovery period. Based on the results, the No Observable Adverse Effect Level (NOAEL) of BNP-166 soft corticosteroid in rat and dog after 28-day oral administration is 2 mg/kg. This value is approximately 40 times higher than that of budesonide. Pharmacodynamic and receptor binding studies have shown BNP-166 to have a similar potency to budesonide; therefore, BNP-166 can be considered safer when administered orally than other corticosteroids such as prednisolone or budesonide.

Study of the bone marrow penetration of radioactivity after oral administration of radiolabelled girisopam (EGIS-5810) in mice.

Girisopam (EGIS-5810) is a potent anxiolytic compound. Recent in vitro studies with the substance, in Chinese hamster ovary cells, indicated dose-dependent mutagenic activity. At the same time, in ex vivo bone marrow micronucleus tests performed after treating CFLP mice with extreme oral doses (875, 1300 and 1750 mg/kg) no mutagenic activity could be observed at any of the dose-levels. On the basis of the above results, it seemed reasonable to study the absorption and distribution of radioactivity and particularly its bone marrow penetration after administering tritiated and 14C-labelled girisopam at the same doses as those applied in the micronucleus test. The animals were sacrificed 30 minutes, 2 and 24 hours after treatment and the radioactivity content of blood, plasma and bone marrow was determined. For whole body autoradiography studies, the animals were sacrificed at the same time points, however they were treated with tritium-labelled girisopam. The results indicated that the absorption of radioactivity from the gastro-intestinal tract of the animals started immediately. The samples collected had well measurable radioactivity even 30 minutes after treatment. At the same time, it was also evident, that, in spite of the high doses, the absolute amount of radioactivity was rather low. At both dose-levels, the radioactivity concentration was the highest in samples collected 24 hours after treatment. This results indicated extremely delayed absorption. The radioactivity level of bone marrow was practically the same as that measured in blood. The samples of animals treated with the high-dose had higher radioactivity content, however the increase was not linearly proportional to the dose. Disproportionality can probably be explained by delayed absorption. The whole body autoradiography was in good agreement with the results of quantitative determinations. This results confirmed the observations obtained by ex vivo micronucleus test. The radioactivity penetrated in the bone marrow resulting a long time exposure of the radioactivity without any mutagenic effect.

[Pharmacokinetic studies of 14C-labeled epervudine in rats]. / 14C-jelzett epervudine farmakokinetikai vizsgálatai patkányokon.

The characteristics of absorption, distribution and elimination of 14C-labelled epervudine were studied in rats treated with 10 mg/kg doses orally and intravenously. The blood level curves were analyzed by appropriate pharmacokinetic models. The results of oral treatment showed a rapid absorption of the radioactivity from the gastrointestinal tracts of the animals (tmax (0.75 h). The elimination rate of radioactivity from blood was fast (t1/2 el = 5.53 h). Blood level curves were characterized by a rapid initial distribution phase after intravenous treatment (t1/2 alpha = 0.17 h). Subsequently, the rate of elimination became slower and the concentration of radioactivity remained at a low level between 2 and 24 hours after the treatment. Studies of distribution did not reveal any specific tissue accumulation. As shown by excretion studies, the elimination of the radioactivity was fast following both the oral and intravenous administration. Within 24 hours ca. 50% excreted with urine and ca. 20% with feces. The ratio areas under blood level curves demonstrated an absorption of 70% (AUCpo: AUCiv x 100).

[Pharmacokinetic studies of epervudine in rats using HPLC]. / Epervudine farmakokinetikai vizsgálata HPLC módszerrel patkányokon.

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.