What does it mean by 'less negative elimination slope'?

What does it mean by 'less negative elimination slope'?

• A. Eliminated more slowly; will be in body longer
• B. Eliminated more quickly
• C. No elimination occurs
• D. Clearance decreases with time

Answer: (A)

In pharmacokinetics, the elimination phase on a semi-log plot has a slope equal to the negative of the elimination rate constant (kel). A “less negative” slope means kel is smaller in magnitude, so the concentration declines more slowly. This corresponds to slower elimination and a longer time for the drug to be cleared, i.e., a longer half-life (t1/2 = 0.693/kel). So the best description is that the drug is eliminated more slowly and will stay in the body longer. The other ideas don’t fit: a steeper (more negative) slope would indicate faster elimination; a flat slope would imply no elimination; and clearance changing with time isn’t implied by a less negative slope in the typical first-order framework where kel (and thus clearance given a fixed volume) is constant.

In pharmacokinetics, the elimination phase on a semi-log plot has a slope equal to the negative of the elimination rate constant (kel). A “less negative” slope means kel is smaller in magnitude, so the concentration declines more slowly. This corresponds to slower elimination and a longer time for the drug to be cleared, i.e., a longer half-life (t1/2 = 0.693/kel). So the best description is that the drug is eliminated more slowly and will stay in the body longer.

The other ideas don’t fit: a steeper (more negative) slope would indicate faster elimination; a flat slope would imply no elimination; and clearance changing with time isn’t implied by a less negative slope in the typical first-order framework where kel (and thus clearance given a fixed volume) is constant.