Determination Of Diclofenac Sodium In Human Plasma By GC-MS

IntroductionDiclofenac sodium is a non-steroidal anti-inflammatory drug(NSAID) with properties of analgesic,anti-inflammatory and antipyretic.These properties are primarily achieved by its ability to block the enzyme cyclooxygenase,but also by an additional direct effect on hyperalgesia due to the functional down regulation of sensitized peripheral pain receptors.The main objective of this study was to develop a simple,selective and sensitive analytical method for the determination of diclofenac sodium in human plasma using liquid-liquid extraction(LLE) and solid phase extraction(SPE) followed by GC/MS.MethodsReagents and materials1.Shimadzu GC-MS QP20102.TDZ4-WS Desktop Centrifuge,DELTA 302 pH,LG WD700(MG5055M) Microwave Ovens3.Diclofenac sodium,Ibuprofen,1,3,5-tribromobenzene(TBB)(National Institute for the Control of Pharmaceutical and Biological Products,Beijing,China)4.Bis-(trimethylsilyl) trifluoroacetamide(BSTFA)(The Ministry of Public Security, Beijing,China)and Heptafluorobutyryl chloride(Wako Pure Chemical Ind.,Ltd.Tokyo, Japan)5.Diatomaceous earth(Wako Pure Chemical Ind.,Ltd.Tokyo,Japan)6.Blank plasma(China Medical University,Shenyang,China)7.Ethanol,Ether,n-hexane,Butyl propionateExperimentalMethod 1:The analytes were back-extracted from acidized plasma,further derivatized with TMS and detected by GC/MS.Selected ion monitoring(SIM) was performed for quantification of diclofenac at m/z 367 and internal standard ibuprofen at m/z 263.Method 2:Used a solid-phase extraction(SPE) as a sample clean-up procedure followed by GC/MS.Selected ion monitoring(SIM) was performed for quantification of diclofenac at m/z 214 and internal standard TTB at m/z 314.ResultsMethod1:The calibration curve was linear within the range of 0.005-10μg·mL-1(r=0.9997),with the minimum limit of quantification at 0.5ng·mL-1.The recoveries were 94%-98%,with both intra-day and inter-day at less than 5%.Method 2:The calibration curve was linear within the range of 0.005-10μg·mL-1(r=0.9978),with the minimum limit of quantification at 0.5ng·mL-1.The recoveries were 79%-88%,with both intra-day and inter-day at less than 8%.ConclusionThe method is rapid,sensitive and suitable for the monitoring of plasma concentration and pharmacokinetics of diclofenac sodium.