Question

pharmacy calculations

A drug is supplied as a 30 mg/ml solution in a 50 mL vial. You need to prepare 10 mL of a 20 mg/ml solution. How much concentrate will be needed for the preparation? A prescriber has ordered 200 ml of an iodine topical solution. The pharmacy's recipe book includes a formula for preparing 800 mL of the solution. Determine how much of sodium iodide will be needed to prepare 200 mL of the solution Current Formula Jodine 30 Sodium iodide 258 qsad to 1000 ml Purified water Dexamethasone is available as a 4 mg/ml preparation; an infant is to receive 0.24 mg. Prepare a dilution so that the final concentration is 1 mg/ml. How much diluent will you need if the original product is in a 1 mL vial and you dilute the entire vial?

Answer 1

1.Available concentration=30mg/ml

Required concentration=20mg/ml

Each ml carries 10 units

Hence each unit/0.1ml=3mg

0.66ml carries 20mg

That is concentration required to prepare 20mg/ml solution is 0.66 ml available solution.

2.Quantity of sodium iodide required for preparing 800ml solution is 25g

Quantity of sodium iodide required for 200 ml =25/4=6.25g(As 800/4=200)

3.To dilute the entire vial to make a concentration of 1 mg/ml we have to add 3 ml of diluent to make total volume of 4 ml.As the available form is 4mg/ml,after the dilution into a total of 4 ml we get a concentration of 1mg/ ml.

To administer the drug to infant another method is;

Dilute1ml of Dexamethasone in 9 ml of diluent to make 10 ml solution,then give 0.6 ml to the infant to give 0.24 mg

Because The prepared 10 ml solution contains 0.4mg/ml,(10/4=0.4)