The Development Of Analytical Method In Plasma And Pharmacokinetic Studideis Of Memantine Hydrochloride In Healthy Chinese Volunteers

Objective:1.To establish a sensitive HPLC-MS/MS method for determination of memantin in human plsma;2.To study the pharmacokinetics of memantine in healthy Chinese volunteers after a single-dose of 5mg,10mg,15mg or a multiple-dose of 10mg of Memantine Hydrochloride Capsule,to investigate the process of absorption,distribution,elimination and dosedependability, and the accumulation after multiple-dose,to provide evidence for clinical rational administration.Methods:1.The plasma samples were analyzed and separated on a Ultimate XB-C₁₈ column (150mm×4.6mm,5μm),eluted with the mobile phase of methanol-water(including 0.5% formic acid)(70:30,V/V) at a flow rate of 0.5 mL·min^-1.The injection volume was 10μL.The column temperature was maintained at 30℃.The mass spectrometer was operated in the positive ion and MRM(multiple reaction monitoring) mode with precursor to product qualifier transition of m/z 180→163 for memantine and m/z 152→135 for IS.The turbo ion spray source temperature was set at 350℃,gas flow 8 L·min^-1,nebulizer 35 psi,and the capillary voltage 4000V.The fragment voltage was optimized at 120V for both memantine and IS. Nitrogen was used as collision gas and collision energy was 18V and 20V for memantine and IS, respectively.The EMV was 400.2.The thirty volunteers were divided into three groups.A single dose of 5mg,10mg,15mg of Memantine Hydrochloride Capsule were orally administrated to the three groups respectively after an ovemight fast.Blood samples were collected before and at 1,2,3,4,5,6,7,8,12,24,48, 96,120,144,192h after administration for 5mg and 1,2,3,4,5,6,7,8,12,24,48,96,120,144, 240h for 10mg and 15mg dose.The blood samples were collected in plastic tubes dealt with heparin and then centrifuged.The plasma was siphoned into plastic tubes and stored at -20℃.3.A multiple dose(10mg once daily for 10days) of Memantine Hydrochloride Capsule was orally administrated to 10 volunteers for 7 days continuously.Blood samples were collected at -48,-24,0,1,2,3,4,5,6,7,8,12,24,48,96,120,144 and 240h after administration,and plasma was siphoned into plastic tubes and stored at -20℃.3.The pharmacokinetic parameters were calculated by DAS 2.0.Adverse effect was observed and recorded during the whole study.Results:1.Good linearity of memantine in plasma was observed in the range of 0.2～100ng·mL^-1(r=0.9981),with a low limit of quantitation(LLOQ) was 0.2ng·mL^-1.The absolute recovery was more than 48%.The relative recovery was 97.37～103.73%.Intra-batch and inter-batch RSD were both less than 7%.Memantine in plasma frozen at -20℃for 21day and after three freeze-thawing cycles was stable,with the RSD ofless than 6%.2.The main pharmacokinetic parameters of memantine after single oral dose of 5mg, 10mg,15mg Memantine Hydrochloride Capsules were as follows:Tmax 5.60±1.17h,5.20±1.99 h and 4.90±1.10h;Cmax 4.449±0.909ng·mL^-1,8.855±1.578ng·mL^-1 and 16.518±2.845ng·mL^-1,AUC_0～t 304.349±33.874ng·mL^-1·h,529.680±118.948ng·mL^-1·h and 1101.144±264.716ng·mL^-1·h,AUC_{0～∞}325.306±30.272ng·mL^-1·h,547.600±126.256 ng·mL^-1·h and 1146.958±272.783 ng·mL^-1·h,t_1/2 47.26±10.26h,46.88±9.27h and 50.73±8.70h.3.The main pharmacokinetic parameters of memantine after multiple oral dose of 10mg, Memantine Hydrochloride Capsules were as follows:Tmax 6.00±1.41h,Cmax 31.776±5.998 ng·mL^-1,AUC_0～240 2276.231±730.134ng·mL^-1·h,AUC_{0～∞}2354.860±782.739ng·mL^-1·h,t_1/2 45.84±8.38h.4.No adverse reactions were observed during the whole studyConclusion:1.The HPLC-MS/MS method developed for the determination of memantine in human plasma in this paper was rapid,sensitive and selective,and successfuUy applied to the memantin pharmacokinetic study after a single or multiple dose administration of Memantine Hydrochloride Capsule.2.An excellent linear correlation was obtained between Cmax,AUC and given doses after single oral dose of 5mg,10mg and 15mg Memantine Hydrochloride Capsules.3.Comparing the pharmacokinetic parameters of single dose and multiple dose,meman-tine may accumulate in human body after a multiple dose of 10mg once daily administration.4.The trial was well done and all volunteers were in good compliance.No adverse reactions were observed during the whole study.