Effects Of Salvia Lyophilized Powder On Pharmacokinetic Parameters Of Nifedipine Tablets In Rats

Objective:In this study,the effects of salvia lyophilized powder injection?the injection of salvia lyophilized powder solution?on the pharmacokinetic parameters of nifedipine tablets in rats were investigated to explore the interaction between the two common clinical representative drugs used in the treatment of cardiovascular diseases.And by the study for the effects of salvia lyophilized powder on the activity of different subtypes of rat isoenzyme CYP450,the interaction mechanism between the two drugs for combined use was further explained,and pharmacokinetic basis for the combined use of the two clinical drugs was provided,the rational combined use of Chinese patent medicines and chemical drugs was promoted,hoping to improve the therapeutic effect,alleviate the patient's pain and further provide reference for the clinical treatment of cardiovascular diseases and rational use of these two types of drugs.Methods:First,a highly sensitive method for measuring nifedipine in biological samples was established:High performance liquid chromatography was used to detect the concentration of nifedipine in plasma,and method validation was performed by selectivity,standard curve and limit of quantitation,precision,accuracy,stability and so on.Second,the effects of salvia lyophilized powder on the pharmacokinetic parameters of nifedipine tablets in rats were studied:24 SD rats,with half male and half female,were randomly divided into 4 groups.21,42,and 84mg/kg of salvia lyophilized powder solution and the same volumes of physiological saline were injected respectively from their tails for 21 consecutive days.On the 7^th day,10mg/kg nifedipine was given to them immediately after respective injection of 21,42,and 84mg/kg of salvia lyophilized powder solution and the same volume of physiological saline from their tails.Blood was taken at 3,5,10,15,30,45 min,1,2,3,4,6,12 and 24 h after administration;HPLC method was used to determine the concentration of nifedipine in plasma,and pharmacokinetic parameters were calculated by DAS 2.0,in order to analyze the effect of salvia lyophilized powder injection on pharmacokinetic parameters of nifedipine tablets in rats;afterwards,the Ultra-high performance liquid chromatography-tandem mass spectrometry?UPLC-MS/MS?for biological sample analysis was established to simultaneously determine the three major metabolic enzymes?Cyp1a2,Cyp3a1,and Cyp2d2?in rats and the corresponding probe substrates?phenacetin,midazolam,dextromethorphan?.24 SD rats were randomly divided into drug administration group?high,middle and low dose group?and blank control group,with 6 rats in each group.In the administration group,the salvia lyophilized powder solution with the concentrations of 21,42 and 84 mg/kg was injected respectively from their tails at 8 o'clock every morning;the same volume of physiological saline was given to the blank control group at the same time;both groups were continuously administered for 7 days.On the 7^th day after the injection of salvia lyophilized powder solution from their tails,the four groups were injected intravenously from the tail veins with the mixed solution of the“cocktail”probe drugs phenacetin,midazolam and dextromethorphan.Blood was collected from the fundus venous plexus at a predetermined time point,and the established UPLC-MS/MS method was adopted to determine the plasma concentrations of the three probe substrates?drugs?in rat plasma of different drug administration groups,and the DAS 2.0 software was used to calculate the main pharmacokinetic parameters of probe substrates of each group for statistical analysis in order to investigate the effect of salvia lyophilized powder injection on the activity of rat enzyme CYP450.Results:The MRT?mean retention time?of nifedipine was somewhat prolonged in combined use of salvia powder injection.Specifically,compared with nifedipine fed alone,after 21,42 and 84mg/kg of salvia lyophilized powder solution were injected from their tails for 21 consecutive days,and the MRTs?0-??of nifedipine were increased respectively by 51.6%?p<0.05?,102.3%?p<0.05?and 73.3%?p<0.01?;and the MRTs of nifedipine were increased significantly in the meddle dose group,so salvia lyophilized powder injection could slow the elimination and excretion of nifedipine in vivo,but it had no effect on other pharmacokinetic parameters.In order to further explain its possible mechanism of action,the UPLC-MS/MS method for the measurement of probe substrates in rat plasma was established.After the rats were injected with high,meddle and low doses of salvia lyophilized powder injection from their tails for 7 consecutive days,the blood concentrations of the probe substrates in drug administration group were measured and compared with those in the blank control group to analyze the differences between drug administration groups and blank control group in the 3 kinds of rat CYP450 enzymes?Cyp1a2,Cyp3a1 and Cyp2d2?and their corresponding probe substrates?phenacetin,midazolam and dextromethorphan?,as well as blood concentration in rats,drug-time curve and main pharmacokinetic parameters AUC,MRT,T_1/2,CL,V,etc.The results showed that the MRT?0-t?and MRT?0-??of the pharmacokinetic parameters in the middle-dose?ie,the clinical recommended dose?group of the salvia lyophilized powder were significantly higher?p<0.05?,and continuous dose administration for the salvia lyophilized powder may have certain inhibitory effects on the metabolism of enzymes Cyp1a2,Cyp3a1 and Cyp2d2 in rats.Conclusion:Experiments showed that the MRT of nifedipine in rats was somewhat prolonged in the combined use of salvia lyophilized powder injection,and the action time in vivo was increased and related to the administration dose of salvia lyophilized powder.In combined use of middle dose salvia lyophilized powder injection?ie,clinical dose?,the MRT of nifedipine in rats was significantly prolonged,which was statistically significant.The possible mechanism of action was that the continuous administration of salvia lyophilized powder might inhibit the metabolic activity of Cyp1a2,Cyp3a1 and Cyp2d2 enzymes in rats to a certain extent.