70.某藥在體內之排除完全經由CYP2D6及CYP3A4兩種酵素之代謝作用,已知CYP2D6及CYP3A4對此藥之代謝 參數如下表,當藥物之穩定狀態血中濃度為0.1mg/L時,經由CYP2D6及CYP3A4代謝之排除速率約占總排除速率分別為何?
(A)82%及18%
(B)67%及33%
(C)33%及67%
(D)18%及82%
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統計: A(4554), B(260), C(546), D(519), E(0) #1631560
統計: A(4554), B(260), C(546), D(519), E(0) #1631560
詳解 (共 1 筆)
#2369692
根據Michaelis - Menten kinetics
排除速率V = ( VMAX x Cp ) / ( KM + Cp )
V2D6 = (10 x 0.1)/(1 + 0.1) = 0.909
V3A4 = (100 x 0.1)/(50 + 0.1) = 0.2
所占排除速率為
V2D6 : V3A4 = 0.909:0.2 = 82% : 18% 選(A)
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