Abstract: 【Abstract】 Objective To explore the effects of oxytocin in pharmacokinetic changes in the late pregnancy and cesarean section rats, for the clinical application of oxytocin. Methods 36 SPF grade SD rats were randomly divided into 6 groups, 6 rats in each group. A, B, C three groups were late pregnancy rats intravenously given 0.1, 0.5, 5 U/kg of oxytocin. D, E, F groups were cesarean section rats given by tail channels 0.1, 0.5, 5 U/kg of oxytocin. All the rats were collected blood at 1, 2, 4, 6, 8, 10, 15, 20, 45, 60 min after injection. We use the high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) to detect the plasma concentration of oxytocin. The pharmacokinetic parameters such as half-life (T1/2), area under the drug concentration time curve (AUC), mean residence time (MRT), apparent volume of distribution (Vd) andplasma clearance (CL) of oxytocin were calculated according to the plasma concentration which has been measured. Statistical analysis were used with analysis of variance. Results ① In the range of 0.01-300 U/L, oxytocin plusmconcentration and peak area had good linear relationship, and the regression equation was y= 1143.36x + 8.78(R2 = 0.9983). The plasma samples extraction recovery rate was high. ② In the late pregnancy group, theplasma concentration increased after injection. There were significantly differences among group A, B andC (P<0.05) . Compared with group A , T1/2 of group B and C were shorter (P<0.05). Compared with groupA and B, the MRT of group C was also significantly shorter (P<0.05). Compared with group A, the CL of group C increased significantly (P<0.05). AUC of three groups had significantly differences (P<0.05). With the increase of drug concentration, AUC showed an increasing trend. ③ After injection of oxytocin, the Tmaxof group D, E and F were 1 min after injection. The maximum concentration (Cmax) of the three groups hadsignificant differences (P<0.05). Compared with the group D, T1/2 of group E and F were significantly shorter(P<0.05). Compared with group D and E, MRT of group F was also significantly shorter (P<0.05). Comparedwith group D, the CL of group F increased significantly (P<0.05). AUC of the three groups had significantlydifferences (P<0.05). As the concentration increased, AUC showed an increasing trend. Conclusions Thehalf-life of oxytocin is about 7-10 min in the late pregnancy and cesarean section rats, and the peak time is 1min. The best way of administration of oxytocin is continuous intravenous drip. At the same time, with the increase of oxytocin concentration, the metabolism of oxytocin accelerates. T1/2 and MRT shorten, while Vd, CL and AUC increase.
刘婷婷 曲冬颖. 缩宫素在妊娠晚期及剖宫产术后大鼠体内的药代动力学研究[J]. 发育医学电子杂志, 2022, 10(1): 31-37,69.
Liu Tingting, Qu Dongying. Study on pharmacokinetics of oxytocin in the late pregnancy and cesarean section ra. Journal of Developmental Medicine(Electronic Version), 2022, 10(1): 31-37,69.
2022, Vol. 10 
