Determination Of Zolpidem By LC-MS/MS In Dog Plasma:Application To The Group Comparison Study Of The Pharmacokinetics Profiles Of Zolpidem Tartrate Sublingual Tablets And Sprays

Zolpidem is an imidazopyridine and is not a benzodiazepine,but zolpidem acts as a benzodiazepine receptor agonist.It has a high binding affinity for the benzodiazepine receptor,which acts as a positive allosteric modulator of the GABAa receptor.Benzodiazepine receptor agonists,such as zolpidem,increase the neuronal transmembrane influx of Cl-ions,which results in neuronal hyperpolarization and decreased neuronal excitability.Zolpidem a typical representative of the third generation of sedative hypnotics because of its rapid onset,good efficacy,high bioavailability,low side effects and other advantages,has been widely used in clinical practice.In this study,the pharmacokinetics of zolpidem tartrate sublingual tablets preparation and zolpidem tartrate sprays and their reference were studied.Zolpidem tartrate was rapidly decompose into tartaric acid and active substance zolpidem in vivo of dogs.Therefore,we developed and validated an LC-MS/MS method for the determination of zolpidem to study its pharmacokinetic profiles in dog.The data was fitted by DAS pharmacokinetics fitting software.The non-compartmental model statistical moment method was used to fit pharmacokinetics parameters of Zolpidem.The results are as follows:1.The Endogenous impurities of Beagle dog plasma do not interfere with the determination of zolpidem in the established LC-MS/MS method;Calibration curves of zolpidem were linear over the concentration ranges of 0.1-50 ng/mL with the coefficients(r2)above 0.99;The lower limits of quantification were 0.1 ng/mL.The matrix effect of zolpidem was 77.3%-81.8%;Intra-and inter-day precisions were less than 8.89%and 10.9%,respectively;Intra-and inter-day accuracies were ranged from-9.20%to 9.44%,and 1.13%to 4.47%,respectively.Dilution accuracy and precision were tested using ten-folds dilutions and was 4.40%and 5.79%,respectively.the stability of pre-process of ice bath(Ice bath for 6 h),stability of the ice bath after 6 h of treatment,the stability of the autosampler(for 8 h),the long-term cryopreservation stability(-80°C placed 60 days)and freeze-thaw stability test(repeated freezing and thawing 3 times).were all fit the biological sample analysis requirements.Thus,this method is suitable for the analysis of zolpidem in dog plasma samples.2.The plasma concentration of zolpidem of spray administration was analyzed by DAS 2.1.1 pharmacokinetics software at different time points.The pharmacokinetics parameters were calculated by non-compartmental model statistical moment method.The peak time Tmax of zolpidem in plasma was 0.500 ± 0.261 and 0.68 ± 0.371 h,respectively.after administration of the reference preparation and the test preparation.The CmaX of the drug-related parameters were 59.3 ± 54.5 and 47.6 ± 54.0?g/L,respectively;the AUC(o-t)were 92.7 ± 69.8 and 72.1 ± 35.4 ?g/L h,respectively;the t1/2 were 1.74 ± 1.81 and 1.12 ± 0.250 h,respectively.The student t test analysis showed there are no significant different between the pharmacokinetic profiles of test preparation and reference preparation of zolpidem tartrate sprays.3.The plasma concentration of zolpidem of sublingual administration was analyzed by DAS 2.1.1 pharmacokinetics software at different time points.The pharmacokinetics parameters were fitted by non-compartmental model statistical moment method.The peak time Tmax of zolpidem in plasma was 1.13±1.18 and 0.771±0.198 h,respectively.after administration of the reference preparation and the test preparation.The Cmax of the drug-related parameters were 22.8±19.3 and 19.5±9.08 ?g/L,respectively;the AUC(o-t)were 43.1±31.3 and 36.8±13.5 ?g/Lh,the t1/2 were 1.53±1.61 and 1.17±0.276 h,respectively.The student t test analysis showed there are no significant different between the pharmacokinetic profiles of test preparation and reference preparation of zolpidem tartrate sublingual tablets.The results showed that the pharmacokinetics characteristics of the two preparations after administration of Beagle dogs were consistent.