Question

To assess the acute toxicity of caffeine, rats were administered caffeine in corn oil by oral gavage. The average body mass of the rats was 500g and the median fatal dose was 96 mg. Estimate the the LD50.

Question 13 options:

1)	LD50 rat, oral gavage 96 mg/kg

2)	LD50 rat, oral gavage 47.5 mg/kg

3)	LD50 rat, oral gavage 192 mg/kg

4)	LD50 rat, oral gavage 192 mg

Answer 1

Answer is option B LD50 Rat;oral gavage 47.5mg/kg.

This question is a very simple question and it is a tricky question . The LD50 is also known as Median lethal dose or Median fatal dose.

As given in the question it is given earlier the Median fatal dose was 96 mg for 500 gm mice so

as in the options it is asked for the value in mg/kg

so we will convert 500gm to kg which is

500/1000=1/2kg

now LD50 will be 96mg×1/2kg=48mg/kg

so this answer resembles the 2nd option which is 47.5mg/kg it is the answer.