Please help!?

Question

A solution contains 65mg/ml of sodium pentobarbitol What volume of this drug would be appropiate to adminster to a 33 gram lab rat at a dose of 40mg/kg

Answer 1

well, it's easy

you have a rat of 33g, so calculate the dose: 0.033kg*40mg/kg = 1.32mg of pentobarbital
now you know the concentration of your solution no ?
1.32 mg / 65 mg/ml = 20.3 microliters

I suggest you to dilute a 100 times your solution of pentobarbital in order to deliver the rat with 1-2ml, if you want reproducible results.