You have a stock solution of epinephrine at a concentration of 1 mg/ml. knowing that the pipette you will use delivers 20 drops/ml, a. calculate the number of drops of the stock solution that must be added to a smooth muscle bath containing 25 ml of locke’s solution so that the final concentration of epinephrine in the muscle bath will be 100 µg/ml, and

Answer : The number of drops pf the stock solution mist be added are, 50 drops.

Explanation :

As we are given that the concentration of stock solution 1 mg/mL and pipette delivers 20 drops/mL. That means,

1 mg of epinephrine = 1 mL = 20 drops

The final volume of Locke's solution = 25 mL

and the final concentration needed =

As, 1 mL of solution contains =

So, 25 mL of solution contains =

Conversion used :

Now we have to determine the number of drops needed.

As, 1 mg of epinephrine contains 20 drops.

So, 2.5 mg of epinephrine contains 2.5 × 20 = 50 drops.

Therefore, the number of drops pf the stock solution mist be added are, 50 drops.