Somogyi A, Eichelbaum M, Gugler R
Eur J Clin Pharmacol. 1982;22(1):85-90. doi: 10.1007/BF00606430.
For drugs with a high hepatic clearance, bioavailability is low due to the so-called "first pass effect". Prediction of the bioavailability for these drugs has been only loosely tested. It is proposed that by plotting the reciprocal of bioavailability versus the oral clearance, a straight line with intercept of unity and slope of reciprocal of hepatic blood flow should ensue. For lignocaine and verapamil, this relationship was found to be strong and gave good predictability, whereas for propranolol this relationship was weak and gave poor predictability. The proposed method may be of value in determining whether the low bioavailability of a drug is due to hepatic first pass metabolism.
对于具有高肝脏清除率的药物，由于所谓的“首过效应”，其生物利用度较低。这些药物生物利用度的预测仅经过了粗略测试。有人提出，通过绘制生物利用度的倒数与口服清除率的关系图，应该会得到一条截距为1且斜率为肝血流量倒数的直线。对于利多卡因和维拉帕米，发现这种关系很强且具有良好的预测性，而对于普萘洛尔，这种关系较弱且预测性较差。所提出的方法在确定药物的低生物利用度是否归因于肝脏首过代谢方面可能具有价值。
