Pharmacokinetic Study Of Combined Application Of Atorvastatin And Dexamethasone In Rats

Objective:Establish an LC-MS/MS method that can simultaneously detect atorvastatin（ATV）and its active metabolites o-hydroxyatorvastatin（o-ATV）,p-hydroxyatorvastatin（p-ATV）and dexamethasone,to explore the pharmacokinetics of ATV and DXM in rats,to investigate the drug-drug interactions of ATV and DXM combined administration.At the same time,the consistency of the pharmacokinetics of ATV produced by different producers in rats was investigated.Method:Take 500μL of rat plasma sample,add 10μL of 5%acetic acid aqueous solution,use d5-atorvastatin（d5-ATV）,rosuvastatin（RSV）and d5-dexamethasone（d5-DXM）as internal standards Ester liquid-liquid extraction,using ACQUITY UPLC BEH C18 column（1.7μm,2.1 mm×50 mm）for liquid phase separation,the mobile phase is 0.01%formic acid acetonitrile-0.01%formic acid water.Electrospray ionization source positive ion（ESI+）mode,quantitative analysis of analyte characteristic ions in multiple reaction monitoring mode for analysis.The ion reactions used for quantitative analysis were ATV m/z 559.39→440.41;d5-ATV m/z564.45→445.40;o-ATV m/z 575.56→440.48,p-ATV m/z 575.49→440.49.RSV m/z482.37→258.40;DXM m/z 393.03→237.02;d5-DXM m/z 398.37→240.20.According to the Chinese Pharmacopoeia 2015 edition,FDA and other biological sample analysis requirements,a complete methodological experiment was conducted on the established method.In this experiment,Sprague-Dawley rats were randomly divided into Lipitor group（original ATV group）,Lunan ATV group（domestic ATV group）,DXM group,Lunan Atorvastatin dexamethasone compound preparation group（composite preparation group）)Combined with Lipitor in the dexamethasone group（combination medication group）,and containing a single dose of 2.7mg/kg atorvastatin and/or 0.2mg/kg dexamethasone acetate by intragastric administration,via the orbital fundus vein Plexus takes venous blood of rats at 15min,35min,1h,1.5h,2h,3h,4h,6h,8h,12h and 24h to separate the plasma samples,after the above verification LC-MS/MS method is processed for detection and analysis,DAS 3.0Calculate time-blood drug concentration data and calculate pharmacokinetic parameters.Results:The linear range of ATV,o-ATV and p-ATV in rat plasma is 0.083～50ng·m L^-1,the linear range of DXM is 2.05～500 ng·m L^-1,and the linear regression coefficients r² were>0.99,linear Good relationship.The inter-day and intra-day imprecision（RSD）of each analyte is less than 15%,and the accuracy（RE）is between-6.52 and 11.95%.The recovery rate of each analyte was greater than 69.18%.The methodological test results meet the requirements of"Chinese Pharmacopoeia"and FDA biological sample analysis methods. In the pharmacokinetic experiment of oral single-dose atorvastatin calcium and dexamethasone acetate in rats,the pharmacokinetic parameters showed that the ATV Cmax of the co-administration group increased by 0.388 times compared with the original ATV group,AUC_（0-t）increased by 1.156 times.The C_max of o-ATV and p-ATV in the co-administration group had no significant change compared with the original ATV group,but the AUC_（0-t）of the two groups increased by 1.320 and 1.209times,respectively.Compared with the domestic ATV group,the Cmax of plasma ATV,o-ATV and p-ATV in the composite tablet group increased by 2.236-2.751 times,and AUC_（0-t）increased by 0.701 times,1.671 times and 0.951 times. When DXM is used in combination with ATVs of different manufacturers,Cmax,AUC0-t and AUC0-∞of DXM will increase slightly,and their pharmacokinetic parameters change in the same direction. Comparing the pharmacokinetic differences of atorvastatin calcium dosage forms of different manufacturers in rats,the results showed that the C_max and AUC of ATV,o-ATV and p-ATV were significantly lower after oral administration of domestic ATV in rats In the original research ATV group,each active drug t_1/2 was significantly shortened.The pharmacokinetics of atorvastatin calcium tablets produced by the two manufacturers are very different in rats,and the pharmacokinetic results are not equivalent. The results of comparing the compound preparation group with the combination medicine group showed that there were significant differences in AUC_0-t and AUC_0-∞of ATV,o-ATV and p-ATV,and the size of the difference was similar to the domestic ATV compared to the original ATV group,while the domestic ATV and DXM After making the compound dosage form,the C_max of each active drug increased significantly in rats.Conclusion:In this experiment,the LC-MS/MS method was established for the first time to detect the drug concentrations of ATV,o-ATV,p-ATV and DXM in rat plasma simultaneously.The methodological test results meet the requirements of the Chinese Pharmacopoeia and FDA biological sample analysis methods,and are suitable for the pharmacokinetic studies of atorvastatin and dexamethasone in rats. In the pharmacokinetic experiment of oral single-dose atorvastatin calcium and DXM in rats,the results of comparing the pharmacokinetic parameters of single drug and combination drugs of different manufacturers showed that atorvastatin calcium and dexamethason acetate When combined,it can significantly increase the Cmax and AUC of atorvastatin and its active metabolites in rats,and increase the relative bioavailability of atorvastatin calcium in rats.When DXM is used in combination with ATV of different manufacturers,its Cmax and AUC increase slightly,and its pharmacokinetic parameters change in the same direction.The same dose of DXM promotes the absorption of drugs and active metabolites in the same dose of ATV from different manufacturers similar.ATV and DXM have significant drug interactions in rats. The pharmacokinetics of atorvastatin calcium tablets produced by the two manufacturers are very different in rats,and the pharmacokinetic results are not equivalent.After oral administration of rats,Lipitor has the advantages of Bilunanbeit Pharmaceutical Co.,Ltd.The higher relative bioavailability of atorvastatin calcium produced by the batch. Comparing the results of the compound preparation group and the combination medicine group,the effect of DXM on the same dose of ATV of different manufacturers to promote the absorption of drugs and active metabolites in the body is the same,but there are differences in the pharmacokinetic process.