School of Life Sciences, University of Nottingham, Nottingham, United Kingdom.
Department of Neurology, University of Washington, Seattle, Washington.
Adv Physiol Educ. 2020 Sep 1;44(3):305-308. doi: 10.1152/advan.00018.2020.
The relationship between pH, p, and degree of local anesthetic ionization is quantified by the Henderson-Hasselbalch equation. As presented in standard textbooks, the effect of pH on the degree of ionization of any particular local anesthetic is not immediately clear due to the -axis displaying pH - p, which requires conversion to pH, based on the p for each local anesthetic, a complex process. We present a graphical solution that clarifies the interrelationships between pH, p, and degree of ionization by plotting p on the -axis versus the percentage of unionized local anesthetic on the -axis. The vertical intercept from the -axis to the pH curves allows rapid and accurate estimation of the degree of ionization of any local anesthetic of known p.
pH、p 和局部麻醉剂离解度之间的关系可以通过 Henderson-Hasselbalch 方程来量化。由于 - 轴显示 pH-p，需要根据每个局部麻醉剂的 p 值将其转换为 pH，这是一个复杂的过程，因此在标准教科书中，pH 对任何特定局部麻醉剂的离解度的影响并不直接清楚。我们提出了一种图形解决方案，通过在 - 轴上绘制 p 值与 - 轴上非离子化局部麻醉剂的百分比之间的关系，来澄清 pH、p 和离解度之间的相互关系。从 - 轴到 pH 曲线的垂直截距允许快速准确地估计任何已知 p 值的局部麻醉剂的离解度。
