Section 8.1 – Concentrations and Dilutions
Terminology:
Concentrate:
Dilution:
Diluent:
A solution is the result of mixing: a ______________________ and a _________________________.
The volumes calculated are only ________________________________.
Ex: We will solve most of these using 2 steps:
1. Calculate the amount of concentrate (in mg/g) and the volume of solution needed.
2. Find the amount of diluent, by subtracting the volume of concentrate from the total.
(a) A drug is supplied as a 40mg/mL solution in a 50mL vial. You need to make 10mL of
a 10mg/mL solution. How much concentrate and diluent will be needed?
(b) Prepare 10mL of a 200mcg/mL folic acid solution by using a 5mg/mL stock solution.
How much folic acid and how much diluent will you need?
(c) Prepare 8mL of a 5mg/mL hydrocortisone solution from 100mg/2mL stock solution.
How many milliliters of hydrocortisone and dilunet are needed?
(d) Prepare 20mL of a 50mg/mL drug dilution from a stock of 2g/5mL. How many
milliliters of diluent and stock drug solution will be needed?
(e) A patient needs 10mL of a 4mcg/mL magnesium sulfate solution. You have
10mcg/mL on hand.
a. How much concentrate will you need?
b. How much diluent?
(f) An order calls for 5mL of 50mg/mL Terramycin. On hand you have 200mg/mL
Terramycin.
a. How much concentrate will you need?
b. How much diluent?
(g) An IV of 0.45% sodium chloride 1000mL needs to be infused. The pharmacy carries
only 0.9% sodium chloride 1000mL.
a. How much concentrate will you need?
b. How much diluent?
(h) A patient needs 35% dextrose 500mL. The pharmacy has only 70% dextrose 1000mL
a. How much concentrate will you need?
b. How much diluent?
(i) You have been instructed to add 1.5g of vancomycin to a 1L bag of NS
a. How many milliliters of a 10g vancomycin solution will you place in the bag?
b. Assuming you have a new 10g vial with 1g/10mL concentration, how many
milliliters will remain in the vial after you have prepared the order?