TD50 is defined as what?

• A. The minimum effective dose in 50% of population
• B. Toxic dose for 25% of population
• C. Toxic dose in 50% of population
• D. Therapeutic dose for 50% of population

Answer: (C)

The main idea is the dose at which half of a population shows a toxic effect. TD50 is the dose that produces toxicity in 50% of individuals, typically derived from dose–response curves in toxicology studies. This measure helps gauge safety and compare drugs, and it sits alongside ED50 (the dose giving a therapeutic effect in 50% of the population) and LD50 (the lethal dose for 50%). So the defined concept is a toxic dose in 50% of the population. The other options correspond to TD25 (toxic effect in 25%), the idea of a minimum effective dose, or ED50 (therapeutic effect in 50%), which are not what TD50 represents.