Résumé
The effect of an intramuscular versus intravenous administration of gonadotropin releasing hormone (GnRH) at fixed-time AI (FTAI) on the pregnancy rates of crossbred Bos indicus beef cows was evaluated. Pluriparous nursing calv cows (n=120) were synchronized as follows: d 0 cows received a 2.0 mg injection of estradiol benzoate (EB) and insertion of a controlled intravaginal progesterone releasing device containing 0.558 g of progesterone, d 8 removal of the progesterone device , a 0.15 mg injection of prostaglandin F2α (PGF), a 1.0 mg injection of EB, and 400 IU injection of equine chorionic gonadotropin. Fifty-four hr after PGF, all cows were exposed to FTAI and a 0.084 mg injection of GnRH was administered either via Vena caudalis (n=60), or via Longissimus dorsi (n=60). Cows were inseminated with the same sire and by a single AI technician. Pregnancy was determined by the transrectal ultrasonography on d 40 after AI. Cows receiving the intravenous administration of GnRH had higher (P = 0.04) pregnancy rates than the cows receiving the intramuscular injection of GnRH (65 vs 46.6%, respectively). It was concluded that the intravenous administration of GnRH at the time of AI improved the pregnancy rates of crossbred Bos indicus beef cows submitted to FTAI.
Résumé
The main purpose of this study was to evaluate the pharmacokinetics of levosulpiride in humans after single and multiple intramuscular injections. Six males and six females received single dose of either 25 mg or 50 mg levosulpiride, or multiple doses of 25 mg every 12 h for 5 consecutive days. In the single 25 mg study, the mean peak plasma concentration (C max) was 441 ng/mL, the mean area under the concentration-time curve from 0 to 36 h (AUC0-36) was 1724 ng h/mL, and the mean elimination half-life (t 1/2) was 7.0 h. In the single 50 mg study, the mean C max was 823 ng/mL, the mean AUC0-36 was 3748 ng·h/mL, and the mean t 1/2 was 6.8 h. After multiple doses of 25 mg levosulpiride, the average plasma concentration (C av) was 136 ng/mL, the fluctuation index (DF) was 3.60, and the accumulation ratio (R) was 1.2. Levosulpiride injections appeared to be well tolerated by the subjects, and can be used for successive administration.
Résumé
The pharmacokinetics of 16-dehydropregnenolone (16-DHP),a sterols compound isolated from Solanum lyratum Thunb.,was investigated in rats following a single intramuscular administration (40 mg/kg).The concentration of 16-DHP in rat plasma was determined by a high performance liquid chromatography (HPLC) method with UV detection.Levonorgestrel was used as the internal standard (IS).The pharmacokinetic parameters of 16-DHP were derived by non-compartmental method.After a single intramuscular administration,the maximum plasma concentration (Cmax,) was (289 ±25)ng/mL,time to reach Cmax(tmax) was (0.38±0.14) h,the elimination half-life (t1/2) was (2.5±1.1)h,the area under the plasma concentration-time curve from time zero to the time of the last measurable concentration (AUC10-t)) was (544 ± 73 )ng· h/mL.The results indicated that 16-DHP was alsorbed quickly and eliminated rapidly in rats after the intramuscular injection.
Résumé
The pharmacokinetics of 16-dehydropregnenolone （16-DHP）, a sterols compound isolated from Solanum lyratum Thunb., was investigated in rats following a single intramuscular administration （40 mg/kg）. The concentration of 16-DHP in rat plasma was determined by a high performance liquid chromatography （HPLC） method with UV detection. Levonorgestrel was used as the internal standard （IS）. The pharmacokinetic parameters of 16-DHP were derived by non-compartmental method. After a single intramuscular administration, the maximum plasma concentration （Cmax） was （289±25）ng/mL, time to reach Cmax（tmax） was （0.38±0.14） h, the elimination half-life （t1/z） was （2.5±1.1）h, the area under the plasma concentration-time curve from time zero to the time of the last measurable concentration （AUC（0-t）） was （544± 73）ng· h/mL. The results indicated that 16-DHP was absorbed quickly and eliminated rapidly in rats after the intramuscular injection.