Aspirin is a weak acid drug (pKa 3.5) and propranolol is a weak base (pKa 9.5). Which ONE of the following statements regarding their in vivo disposition is correct?

Question

BlackTom AI · Accepted Answer

Question restatement: The prompt asks which statement about the in vivo disposition of aspirin (a weak acid, pKa 3.5) and propranolol (a weak base, pKa 9.5) is correct, focusing on ionization and plasma protein binding.
Option A: 'Compared to propranolol, aspirin is more extensively ionized in the stomach and highly bound to serum albumin.' While aspirin is indeed bound to albumin, its ionization depends on pH. In the stomach, which has a very low pH, a weak acid tends to be largely non-ionized, not extensively ionized. Therefore this option is inconsistent with the pH-dependent ionization behavior of aspirin in the gastric environment, making it unlikely to be correct.
Option B: 'Compared to propranolol, aspirin is more extensively ionized in plasma and highly bound to serum albumin.' In plasma (pH ~7.4), aspirin (a weak acid) is mostly ionized, which increases its tendency to bind to serum albumin. Propranolol, a weak base, tends to remain more non-ionized in plasma and can bind to alpha-1-acid glycoprotein as well as albumin, but the key comparison is that aspirin is more ionized in plasma and highly albumin-bound relative to propranolol. This option captures the correct trend about ionization in plasma and albumin binding, aligning with well-known pharmacokinetic principles.
Option C: 'Compared to propranolol, aspirin is more extensively ionized in plasma and highly bound to α1-acid glycoprotein.' Although basic drugs like propranolol interact with α1-acid glycoprotein, aspirin is a weak acid and primarily binds to albumin, not α1-acid glycoprotein. This makes the statement inaccurate regarding the binding partner.
Option D: 'Compared to propranolol, aspirin is more extensively ionized in the stomach and highly bound to α1-acid glycoprotein.' In the stomach, aspirin would not be more ionized; weak acids are less ionized in the highly acidic stomach. Moreover, binding to α1-acid glycoprotein is more characteristic of basic drugs, not aspirin. Thus this option misstates both the ionization environment and the binding protein.
Summary of reasoning: The core concepts are the pH-dependent ionization of acids vs bases and the differential plasma protein binding patterns (albumin for many acidic drugs like aspirin; α1-acid glycoprotein for many basic drugs like propranolol). Therefore, the option stating that aspirin is more extensively ionized in plasma and highly bound to serum albumin correctly reflects these pharmacokinetic principles, while the other options misstate the ionization environment (gastric pH) or the primary binding protein (α1-acid glycoprotein) for aspirin or misattribute ionization.

PCOL2021 2025 Module 3 Practice quiz

Aspirin is a weak acid drug (pKa 3.5) and propranolol is a weak base (pKa 9.5). Which ONE of the following statements regarding their in vivo disposition is correct?

查看解析

登录即可查看完整答案

类似问题

Salbutamol (structure below, pKa 9.3):

Salbutamol (structure below, pKa 9.3):

Which of the following regarding the influence of pH on drug passage through membranes is INCORRECT?

Salbutamol (structure below, pKa 9.3):

For a drug that is a weak base with a pKa of 8.4, the predominant species at pH 7.4 will be:

In a consumer society, many adults channel creativity into buying things

Economic stress and unpredictable times have resulted in a booming industry for self-help products

People born without creativity never can develop it

更多留学生实用工具

考试浏览器助手

风格化写作助手

论文查重助手

文献引用助手

课堂转译助手

课堂笔记助手

Quiz搜索助手

学校历年真题

智能刷题助手

智能匹配练习

希望你的学习变得更简单