建立超效能液相層析－－串聯式質譜儀定量四種抗排斥藥物（tacrolimus, sirolimus, everolimus, cyclosporine）的方法

Development of An Ultra-performance Liquid Chromatography Tandem Mass Spectrometric Method for Simultaneous Quantitating Four Immunosuppressant Drugs (tacrolimus, sirolimus, everolimus, cyclosporine)

監控血中抗排斥藥物濃度的目的是為了有效降低服用抗排斥藥物病人的移植排斥作用，減少藥物副作用與增加器官移植病人的存活率。目前普遍定量抗排斥藥物濃度的方法為免疫法，但因較缺乏專一性，因此準確性較低。本研究建立以超效能液相層析－－串聯式質譜儀(UPLC-MS/MS)同時定量四種抗排斥藥物(tacrolimus, sirolimus, everolimus, cyclosporine)的方法。使用100 μL的全血檢體與簡單的蛋白質沉澱，合併使用on-line solid phase extraction (on-line SPE)，可在4.5分鐘的分析時間中同時定量四種不同的藥物。此方法的線性範圍在tacrolimus, sirolimus, everolimus 與cyclosporine分別為1.1-38.5 ng/mL、1.1-46.1 ng/mL、1.0-41.1 ng/mL與21.3-919.0 ng/mL，相關係數皆大於0.998，準確度由回收率評估，介於90%至113%，不精準度<6.6%，無carryover與ion suppressant現象。與免疫法結果比較發現，免疫法定量結果皆高於UPLC-MS/MS定量結果，尤以sirolimus最為明顯。本研究建立了以UPLC-MS/MS同時定量四種抗排斥藥物的方法，提供臨床檢驗室更準確的定量抗排斥藥物方法。

Monitoring immunosuppressant drug level helps optimizing the drug dosage to decrease rejection, minimize drug toxicity and improve survival rates of transplant recipients. Many immunoassays can be applied for monitoring the concentration of immunosuppressant drugs. The main disadvantage of these immunoassays is cross-reaction between the parent drug and its metabolites, which may cause overestimation of drug concentration. The purpose for this study was to develop a method to quantitate four immunosuppressant drugs (tacrolimus, sirolimus, everolimus and cyclosporine) at the same time by on-line solid phase extraction (on-line SPE) and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). This method showed linearity over the calibrator range, r>0.998 (1.1-38.5 ng/mL for tacrolimus, 1.1-46.1 ng/mL for sirolimus, 1.0-41.1 ng/mL for everolimus and 21.3-919.0 ng/mL for cyclosporine). The accuracy was between 90 % and 113 %. For intra-day and inter-day precision, the CV was <6.6 %. This method showed no carryover or ion suppressant. By comparing the results obtained from our UPLC-MS/MS method to that of immunoassays, we have found that immunoassays overestimate the concentration of these four immunosuppressant drugs, especially for sirolimus. In conclusion, our newly developed UPLC-MS/MS method for simultaneous quantification four immunosuppressant drugs provides a more accurate measurement for immunosuppressant drugs in a clinical laboratory.