protein binding rate of remifentanil in clinical usage

• Project/Area Number: 18K16476
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 55050:Anesthesiology-related
• Research Institution: Hamamatsu University School of Medicine
• Principal Investigator: Ueda Hiroshi 浜松医科大学, 医学部附属病院, 助教 (40748498)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000); Fiscal Year 2020: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2019: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: 蛋白結合率 / 平衡透析 / レミフェンタニル / 臨床使用中 / 臨床 / 人工心肺 / 質量分析

Outline of Final Research Achievements

The protein binding rate of remifentanil is about 75% according to the drug package insert. This is not the actual measurement result during surgery. In this study, we measured the protein binding rate of remifentanil in the blood during clinical use (patients who have actually undergone surgery).
When the protein binding rate was measured by separating unbound fraction that was not bound to protein by the equilibrium dialysis, the protein binding rate of remifentanil in the plasma of patients during clinical use was about 25%.

Academic Significance and Societal Importance of the Research Achievements

薬剤は蛋白に結合していない分画が薬効を示す。試験管内でレミフェンタニルを血漿蛋白に結合させた場合、75％が蛋白に結合し、残る25％が薬効を示すと言う結果だが、本研究では臨床使用中には血中で蛋白に結合しているのは25％程度であり、残る75％が薬効を示す、という結果となった。これは、レミフェンタニルの薬効が実は想定よりも強いかもしれない、と言う可能性を示唆するものである。