Question

Problem 6 Dopamine HCI injection is available in 5-mL vials each containing 40 mg of dopamine HCI per milliliter. The injection must be diluted before administration by intravenous infusion. If a pharmacist dilutes the injection by adding the contents of one vial to 250 mL of 5% dextrose injection, calculate the percent concentration of dopamine HCI in the infusion.

Answer 1

Drug concentration is 40mg/ml dopamine hydrochloride.

5 ml of dopamine hydrochloride drug diluted in 250ml of 5% dextrose injection.

it means 200mg dopamine hydrochloride in 255ml.

1 ml containing 0.78mg(0.8mg) of dopamine hydrochloride.

$\dpi{100} \large 200mg\div 255ml = 0.78mg/ml$

In another way, percent of dopamine hydrochloride in 250ml of dextrose will be 2%

$\dpi{100} \large (5mlDrug\div 250ml 5D)\times100 = 2 Percentage$