[Comparative pharmacokinetics of 800 mg of acyclovir-containing Telviran and Zovirax tablets in healthy volunteers]. / Telviran és Zovirax 800 mg acyclovir hatóanyagtartalmú tabletták összehasonlító farmakokinetikája egészséges önkénteseken.

The authors performed a detailed comparative clinical and pharmacokinetic study with two 800 mg acyclovir containing tablets, namely the Telviran (EGIS Pharmaceuticals Ltd.) and the Zovirax (Wellcome Foundation Ltd.). The determination of the detailed pharmacokinetic parameters and the relative bioavailability was carried out on 24 healthy male volunteers in a two way, open, randomised, cross-over design study after single dose administration. The plasma concentration of acyclovir was determined by a newly developed and validated highly sensitive (LLOQ = 10 ng/ml) HPLC-UV bioanalytical method after sample preparation with RP-18 solid phase extraction method (SPE). The individual pharmacokinetic parameters calculated from the time-plasma concentration curve (tmax, Cmax, AUC0-infinity, AUC0-16, AUC0-t, AUC0-z, AUCRest, t beta 1/2, MRT, Cmax/AUC0-infinity) were compared with statistical methods (ANOVA, ANOVAlog, Confidence interval, Schuirmann, Wilcoxon tests). On the basis of the results of the statistical evaluation and the clinical study, there was no significant difference found between the two acyclovir containing preparations. The comparative pharmacokinetic study demonstrated, that the relative bioavailability of the 800 mg Telviran and Zovirax tablets are equivalent and the two products are bioequivalent.

Food interaction pharmacokinetic study of cordaflex 20 mg retard filmtablet in healthy volunteers.

The aim of the present study was to investigate the effect of food consumption on the pharmacokinetics of Cordaflex 20 mg retard filmtablet in healthy volunteers through measuring nifedipine plasma levels by an HPLC-ED method both after fasting and food ingestion. The food interaction pharmacokinetic study of Cordaflex 20 mg retard filmtablet was carried out in 12 healthy male volunteers treated with a single dose of the preparation both after fasting and after food ingestion, in a crossover design allowing 1 week of wash-out period between the 2 treatments. Nifedipine concentration of plasma samples were determined by an isocratic HPLC-ED method [Horvai et al. 1994] with robotic sample processing [Horváth et al. 1995, 1996]. The pharmacokinetic parameters (AUC0-infinity, AUC0-t, Cmax, MRT) were analyzed by calculating 90% confidence interval for logarithmic transformed test/reference ratio values, and Schuirmann's statistical tests, the tmax and HVD values were analyzed by Wilcoxon's nonparametric statistical test. The above statistical tests of the present food interaction study indicated significant differences for each one of the respective pharmacokinetic parameter pairs calculated for treatments after fasting and after food ingestion. On the basis of the above findings and also by comparing the mean pharmacokinetic curves, it was evident, that, in agreement with the data of literature [Kleinbloesem et al. 1993, Schall et al. 1994], food ingestion increased the relative bioavailability and maximum plasma concentration (Cmax). Considering the average of the parameter values and also the respective statistical tests, it was also apparent that the time to maximum plasma concentration (tmax), the mean residence time (MRT), and the half-value duration (HVD) all decreased significantly upon the effect of food ingestion.

Pharmacokinetic and bioequivalence study of two gemfibrozil preparations.

A comparative pharmacokinetic study has been performed in 19 healthy male volunteers in a single-dose, randomized, two way cross-over design with two preparations of gemfibrozil (CAS 25812-30-0) capsules each of them containing 300 mg active ingredient. The test preparation was Innogem 300 mg capsule. The plasma concentration of gemfibrozil was determined by a validated HPLC-UV analytical method. The statistical comparison of individual pharmacokinetic parameters (AUC0-16, AUC0-oc Cmax, tmax) of the two capsule preparations was performed by three-way analysis of variance (ANOVA), Wilcoxon's, Westlake's, Schuirmann's and Hanck-Anderson's method as well as by the calculation of confidence intervals on the ratio of test/reference. The relative bioavailability of the test preparation with respect to the reference preparation in terms of the AUC0-oc was 104.06 +/- 21.61%. No statistically significant difference was found between the pharmacokinetic parameters, calculated from plasma concentration-time curves, indicating that the two preparations were bioequivalent.

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.

[Human pharmacokinetic study of nerisopam and its n-acetyl metabolite]. / A nerisopam és N-acetil metabolitjainak humán farmakokinetikai vizsgálata.

It was established during the human phase I study of nerisopam, a new anxiolytic drug, that nerisopam (EGIS-6775) shows two, while N-acetyl metabolite (EGIS-7649) shows one compartmental pharmacokinetic behaviour. Acetylation of nerisopam is polymorph, so that volunteers belonging into slow or fast acetylating group show significantly different plasma concentration. Observed pharmacokinetic differences are primarily manifested in the absorption phase, and not in the elimination one. Accordingly, slow acetylators have higher nerisopam levels, while fast acetylators possess higher metabolite levels. Elimination phase is practically parallel for both compounds. At the same time, significant differences are found in the AUC and Cmax values. Nerisopam is rapidly absorbed, but N-acetyl metabolite is appeared especially fast in the blood. Our consideration is, that nerisopam undergoes significant "first-pass" metabolism process, the extent of which is different between the two acetylator phenotypes.

Food interaction study of a new theophylline (Egifilin) 200 and 400 mg retard tablet in healthy volunteers.

The aim of the present food interaction study was to determine the blood plasma levels of theophylline upon the administration of new Egifilin 200 and 400 mg retard tablets, either on an empty stomach or after meal, and to make comparative pharmacokinetic evaluation in 26 healthy volunteers. For determination of the plasma levels of theophylline an improved isocratic HPLC-UV method was used in the concentration range of 0.1-18 micrograms/ml. The mean pharmacokinetic curves obtained with 200 and 400 mg tablets before and after meal were in good agreement also on the basis of statistical evaluation, although, as usual with theophylline, the evaluation of the individual pharmacokinetic curves indicated great variations. The pharmacokinetic parameters (AUCzero-t, AUCzero-infinity, HVD, MRT, Cmax, tmax) calculated for Egifilin 200 and 400 mg retard tablets were analyzed by ANOVA, ANOVAlog, Wilcoxon, and Schuirmann statistical tests as well as by the confidence interval calculation. As it was found, under the circumstances of the present food interaction study, food consumption did not have a biologically significant effect on the pharmacokinetic parameters of either the 200 or the 400 mg Egifilin retard preparations.

[Bioanalysis of gemfibrozil. Comparative human pharmacokinetics of 300 mg of gemfibrozil-containing Innogem and Lopid capsules]. / A gemfibrozil bioanalitikája Innogem és Lopid 300 mg kapszulák humán összehasonlító farmakokinetikai vizsgálata.

Comparative pharmacokinetic study was performed in 19 healthy male volunteers in a single-dose, randomized, two way cross-over trial on two preparations of gemfibrozil (Innogem and Lopid capsules) each of them containing 300 mg active ingredient. After administration either the test preparation (Innogem, EGIS Pharmaceuticals Ltd.,) or the reference preparation (Lopid, Parke-Davis) in human, the plasma concentration of gemfibrozil was determined by validated HPLC-UV (225 nm) bioanalytical method. After the relatively simple liquid-liquid extraction of the plasma samples the separation was carried out under isocratic condition on Nucleosil 10, C-18 column. On the basis of the validation process the limit of quantitation (LOQ), of the HPLC method was 250 ng/0.5 ml. All the validation parameters fell within the internationally accepted range. The comparison of individual pharmacokinetic parameters (AUC0-16, AUC0-infinity Cmax, tmax) of the two capsule preparations was accomplished by three-way analysis of variance (ANOVA), Wilcoxon's, Westlake's, Schuirmann's and Hauck-Anderson's method as well as by the calculation of confidence intervals on the ratio of test/reference values. The relative bioavailability of Innogem with respect to Lopid 300 mg capsule for AUC0-infinity was 104.06 +/- 21.61%. No statistically significant difference was found in the clinical results and between the pharmacokinetic parameters calculated from plasma concentration-time curves indicating that the two gemfibrozil preparations were bioequivalent after single administration.

[Endocrine effect of a new anti-estrogen compound (EGIS-5650, panomifene) in healthy volunteers: phase I/a study]. / Az antisztrogén hatású új vegyület (EGIS-5650, panomifene) endokrin hatásairól egészéges önkénteseken: fázis I/a vizsgálat.

Influence of a new Hungarian antiestrogen, panomifene (PAN) was investigated on some hormone levels of 10 postmenopausal healthy women during a partially double-blind placebo controlled phase I/a study. Following a single oral administration of PAN serum estradiol (E2), follicle-stimulating hormone (FSH), luteinizing hormone (LH) and prolactin (PROL) levels were measured by RIA at two selected dose levels: 12 mg and 120 mg. The low dose (12 mg) results in an increased E2 level in some cases probably due to the intrinsic estrogenic (agonistic) character of the drug. The high dose (120 mg) seems to have a strong antiestrogenic (antagonistic) action. FSH and LH changed within the normal postmenopausal range at both doses, PROL slightly decreased at 12 mg dose level. During the 14-day follow up, the 120 mg PAN considerably suppressed the PROL secretion proving the antiestrogenic character of the "high" dose. PAN seems to be a safe tamoxifen analogue, the single oral dose of which does not exert any noteworthy (pathogenic) side effect on some hormone levels of healthy women.