After six half-lives, how much of a drug remains in the body?

After six half-lives, the amount of a drug remaining in the body can be determined using the half-life concept, which states that after each half-life, half of the remaining drug is eliminated from the body. This leads to a predictable decrease in drug concentration.

To break down the process:

1. After the first half-life, 50% of the drug remains.

2. After the second half-life, 25% remains (half of 50%).

3. After the third half-life, 12.5% remains (half of 25%).

4. After the fourth half-life, 6.25% remains (half of 12.5%).

5. After the fifth half-life, 3.125% remains (half of 6.25%).

6. After the sixth half-life, 1.5625% remains (half of 3.125%).

Rounding 1.5625% gives approximately 1.56%. Consequently, this means that after six half-lives, 98.44% of the drug has been cleared from the body.

This understanding illustrates why the correct choice indicates that 98.43% clearance corresponds to 1.56% remaining in