Percentage Calculations Percentage Calculations Dont let percentages fool

Percentage Calculations

Percentage Calculations Don’t let percentages fool you! Percentages are just ratios in disguise!

Percentages There are 3 types of percentages in pharmacy calculations: 1. Percent weight-in-weight (w/w) 2. Percent volume-in-volume (v/v) 3. Percent weight-in-volume (w/v) The units of these percentages will ALWAYS be GRAMS or ML

Percentage Calculations •

Percentage Calculations •

Percentage Calculations Interpreting the type of percentage can only be done with practice. So, let’s do some practice problems- together!

Question #1 Iodine tincture is available as a 2% solution of iodine. How many grams of iodine will be contained in 40 m. L of tincture?

Answer #1 •

Question #2 You have 25 grams of a drug and need to compound a 30% solution. How many m. L will you prepare?

Answer #2 •

Question #3 You add 80 grams of a drug to 600 m. L of sterile water. What is the percentage strength of the solution prepared?

Answer #3 •

Question #4 You have an order for 2 g of calcium gluconate to add to a 1000 m. L bag of 5% dextrose injection. The label on the calcium gluconate vial gives the concentration as 10% and 0. 465 m. Eq/m. L. How many m. L of calcium gluconate will you need to use?

Answer #4 •

Question #5 The technician is to prepare 30 m. L of a 20% solution using 300 mg tablets. How many tablets are needed?

Answer #5 •

Question #6 You have on hand 500 mg of a powder. How many m. L of a 2% solution can you prepare?

Answer #6 •

Question #7 Devonex is a topical ointment available in a 0. 005% concentration. How many mg of the active ingredient are contained in 60 g?

Answer #7 •

Question #8 Devonex is a topical ointment available in a 0. 005% concentration. How many mg of the active ingredient are contained in 60 g?

Answer #8 •

Question #9 You have in stock a 30 m. L vial of 23. 4% concentrated sodium chloride injection. How many grams of sodium chloride are in the vial? How many mg are in 1 ml?

Answer #9 •

Question #10 Hydrocortisone topical cream is available as a 0. 2% concentration in 454 grams. How many mg of hydrocortisone are in the product?

Answer #10 •

Question #11 A medication is available as 1 g/3 m. L in 20 m. L vials. Express this drug concentration as a percentage strength.

Answer #11 •

Question #12 A physician orders 450 mcg of a medication. The med is available as a 0. 025% solution. How many m. L will be required to fill the order?

Answer #12 •

Question #13 You need to prepare 750 m. L of a 1: 500 w/v potassium permanganate solution. How many grams are needed?

Answer #13 •

Question #14 A 1: 50, 000 lidocaine solution is to be given to a patient. What is the concentration of the solution in mcg/m. L?

Answer #14 •

Question #15 A technician is to add 1. 2 mg of a drug to a 25 m. L bag of 5% dextrose injection. On hand is a 2 m. L ampoule of a 1: 1, 000 w/v solution. How many m. L should be added to the bag?

Answer #15 •

Question #16 A technician is asked to prepare 350 m. L of a 22% boric acid solution from a 50% boric acid solution and purified water. How many m. L of 50% solution and water will be needed?

Answer #16 • 50 22 22 0 28 = 50 total parts

Question #17 Stock solutions of 27% and 31% are available in the pharmacy. How many m. L of each stock solution are needed to prepare 2 L of a 29% solution

Answer #17 • 31 2 29 27 2 = 4 total parts

Question #18 An order for 6 L of 0. 9% sodium chloride solution is to be prepared from 23. 4% concentrated Na. Cl solution and sterile water for injection. How many m. L of each should be used?

Answer #18 • 23. 4 0. 9 0 22. 5 = 23. 4 total parts