A drug having 40% absorption and hepatic extraction ratio of 0.6. What is the bioavailability of that drug?
**Core Concept**
The bioavailability of a drug is the fraction of the administered dose that reaches the systemic circulation and is available at the site of action. It is influenced by factors such as absorption, distribution, metabolism, and excretion (ADME). In this question, we are given the absorption rate (40%) and hepatic extraction ratio (0.6), and we need to calculate the bioavailability.
**Why the Correct Answer is Right**
To calculate the bioavailability, we use the formula: Bioavailability (F) = (1 - Hepatic Extraction Ratio) x Absorption Rate. Plugging in the given values, we get F = (1 - 0.6) x 0.4 = 0.4 x 0.4 = 0.16. This means that only 16% of the administered dose reaches the systemic circulation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not take into account the hepatic extraction ratio.
**Option B:** This option is incorrect because it simply states the absorption rate without considering the hepatic extraction ratio.
**Option C:** This option is incorrect because it is a random value that does not relate to the given information.
**Clinical Pearl / High-Yield Fact**
Remember that bioavailability is a critical parameter in pharmacokinetics, and understanding its calculation is essential for predicting the efficacy and safety of a drug. In clinical practice, bioavailability can be affected by various factors, including food, disease state, and drug interactions.
**Correct Answer:** C. 0.16