**Question:** Voluntareer Ram will receive a new drug in Phase 1 clinical trial. The clearance and volume of distribution of the drug in Ram are 1.386L/hr and 80L respectively. The life of the drug in him would be approximately

**Core Concept:**

*Pharmacokinetics* refers to the study of how the body absorbs, distributes, and eliminates drugs. In Phase 1 clinical trials, drugs are tested for safety and pharmacokinetic parameters such as clearance (CL) and volume of distribution (Vd) are measured. These parameters help determine the drug's half-life.

The **Clinical Trial Phase** is a crucial step in drug development, where safety, efficacy, and pharmacokinetic parameters are assessed. In this case, we are given the clearance (CL) and volume of distribution (Vd) values for the drug in Ram.

**Why the Correct Answer is Right:**

In order to calculate the half-life (t1/2) of the drug, we can use the following formula:

t1/2 = ln(2) / CL

Where:
- t1/2 is the half-life of the drug
- ln(2) is the natural logarithm of 2 (approximately 0.693)
- CL is the clearance (1.386L/hr in this case)

**Why the Other Options are Incorrect:**

*Option A* is incorrect because it does not consider the given clearance and volume of distribution values.

*Option B* is incorrect because it is the reciprocal of the clearance value and does not represent the actual half-life of the drug.

*Option C* is incorrect because it is also the reciprocal of the clearance value, similar to Option B.

**Clinical Relevance and Application:**

Understanding pharmacokinetic parameters like clearance and half-life is crucial in drug development, as they help determine how long it takes for a drug to be eliminated from the body. The half-life helps doctors adjust the drug dose for optimal treatment outcomes. A higher half-life indicates a drug that stays in the body for longer periods, potentially leading to fewer dosing intervals; conversely, a shorter half-life indicates a drug that is eliminated from the body quickly, requiring more frequent dosing.

**Explanation of the Formula:**

The half-life calculation involves the natural logarithm of 2 divided by the clearance (CL). The clearance is a measure of how fast the drug is eliminated from the body. A lower clearance value indicates a drug that is cleared more quickly from the body, potentially leading to more frequent dosing.

**Correct Answer Explanation:**

Using the formula t1/2 = ln(2) / CL, we can calculate the half-life of the drug in Ram's body. In this case, the clearance (CL) is given as 1.386 L/hr. Plugging this value into the formula, we get:

t1/2 = ln(2) / 1.386

Calculating