Dont let percentages fool you Percentages are just ratios in disguise Percentages There are 3 types of percentages in pharmacy calculations Percent weightinweight ww Percent volumeinvolume vv ID: 777343
Download The PPT/PDF document "Percentage Calculations Percentage Calcu..." is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Percentage Calculations
Slide2Percentage Calculations
Don’t let percentages fool you! Percentages are just ratios in disguise!
Slide3Percentages
There are 3 types of percentages in pharmacy calculations:
Percent weight-in-weight (w/w)
Percent volume-in-volume (v/v)Percent weight-in-volume (w/v)The units of these percentages will ALWAYS be GRAMS or ML
Slide4Percentage Calculations
Immediately, when you see a percentage, change it to a ratio. It’s always going to be the percentage number over 100.
Example:
3% = 70% =
97% =
Slide5Percentage Calculations
The difficult part will be interpreting which
type
of percentage it is, so you can determine which units to use!Percent weight-in-weight (w/w)Will always be
Percent volume-in-volume (v/v)Will always be
Percent weight-in-volume (w/v)Will always be
Slide6Percentage Calculations
Interpreting the
type
of percentage can only be done with practice. So, let’s do some practice problems- together!
Slide7Question #1
Iodine tincture is available as a 2% solution of iodine. How many grams of iodine will be contained in 40 mL of tincture?
Slide8Answer #1
Iodine tincture is available as a 2% solution of iodine. How many grams of iodine will be contained in 40 mL of tincture?
X = 0.8 grams
Slide9Question #2
You have 25 grams of a drug and need to compound a 30% solution.
How many mL will you prepare?
Slide10Answer #2
You have 25 grams of a drug and need to compound a 30% solution. How many mL will you prepare?
X = 83.3 mL
Slide11Question #3
You add 80 grams of a drug to 600 mL of sterile water. What is the percentage strength of the solution prepared?
Slide12Answer #3
You add 80 grams of a drug to 600 mL of sterile water. What is the percentage strength of the solution prepared?
X = 13.33 grams
13.3%
Slide13Question #4
You have an order for 2 g of calcium gluconate to add to a 1000 mL bag of 5% dextrose injection. The label on the calcium gluconate vial gives the concentration as 10% and 0.465
mEq
/mL. How many mL of calcium gluconate will you need to use?
Slide14Answer #4
You have an order for 2 g of calcium gluconate to add to a 1000 mL bag of 5% dextrose injection. The label on the calcium gluconate vial gives the concentration as 10% and 0.465
mEq
/mL.
How many mL will you need to use?
X = 20 mL
Slide15Question #5
The technician is to prepare 30 mL of a 20% solution using 300 mg tablets. How many tablets are needed?
Slide16Answer #5
The technician is to prepare 30 mL of a 20% solution using 300 mg tablets. How many tablets are needed?
X = 6 grams
6000 mg = 300mg (x)
X = 20 tablets
Slide17Question #6
You have on hand 500 mg of a powder. How many mL of a 2% solution can you prepare?
Slide18Answer #6
You have on hand 500 mg of a powder. How many mL of a 2% solution can you prepare?
500 mg = 0.5g
X = 25 mL
Slide19Question #7
Devonex
is a topical ointment available in a 0.005% concentration. How many mg of the active ingredient are contained in 60g?
Slide20Answer #7
Devonex is a topical ointment available in a 0.005% concentration. How many mg of the active ingredient are contained in 60g?
X = 3 mg
Slide21Question #8
Devonex
is a topical ointment available in a 0.005% concentration. How many mg of the active ingredient are contained in 60g?
Slide22Answer #8
Devonex is a topical ointment available in a 0.005% concentration. How many mg of the active ingredient are contained in 60g?
X = 3 mg
Slide23Question #9
You have in stock a 30 mL 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?
Slide24Answer #9
You have in stock a 30 mL 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?
X = 7.02 grams/30 mL
234 mg/1 mL
Slide25Question #10
Hydrocortisone topical cream is available as a 0.2% concentration in 454 grams. How many mg of hydrocortisone are in the product?
Slide26Answer #10
Hydrocortisone topical cream is available as a 0.2% concentration in 454 grams. How many mg of hydrocortisone are in the product?
X = 0.908 grams = 908 mg
Slide27Question #11
A medication is available as 1 g/3 mL in 20 mL vials. Express this drug concentration as a percentage strength.
Slide28Answer #11
A medication is available as 1 g/3 mL in 20 mL vials. Express this drug concentration as a percentage strength.
X = 33.3%
Slide29Question #12
A physician orders 450 mcg of a medication. The med is available as a 0.025% solution. How many mL will be required to fill the order?
Slide30Answer #12
A physician orders 450 mcg of a medication. The med is available as a 0.025% solution. How many mL will be required to fill the order?
X = 1.8 mL
Slide31Question #13
You need to prepare 750 mL of a 1:500 w/v potassium permanganate solution. How many grams are needed?
Slide32Answer #13
You need to prepare 750 mL of a 1:500 w/v potassium permanganate solution. How many grams are needed?
X = 1.5 grams
Slide33Question #14
A 1:50,000 lidocaine solution is to be given to a patient. What is the concentration of the solution in mcg/mL?
Slide34Answer #14
A 1:50,000 lidocaine solution is to be given to a patient. What is the concentration of the solution in mcg/mL?
X = 0.00002 grams
X = 20 mcg/mL
Slide35Question #15
A technician is to add 1.2 mg of a drug to a 25 mL bag of 5% dextrose injection. On hand is a 2 mL ampoule of a 1:1,000 w/v solution. How many mL should be added to the bag?
Slide36Answer #15
A technician is to add 1.2 mg of a drug to a 25 mL bag of 5% dextrose injection. On hand is a 2 mL ampoule of a 1:1,000 w/v solution. How many mL should be added to the bag?
X = 1.2 mL
Slide37Question #16
A technician is asked to prepare 350 mL of a 22% boric acid solution from a 50% boric acid solution and purified water. How many mL of 50% solution and water will be needed?
Slide38Answer #16
A technician is asked to prepare 350 mL of a 22% boric acid solution from a 50% boric acid solution and purified water. How many mL of 50% solution and water will be needed?
50
22
22
0
28
= 50 total parts
Slide39Question #17
Stock solutions of 27% and 31% are available in the pharmacy. How many mL of each stock solution are needed to prepare 2 L of a 29% solution
Slide40Answer #17
Stock solutions of 27% and 31% are available in the pharmacy. How many mL of each stock solution are needed to prepare 2 L of a 29% solution
31
2
29
27
2
= 4 total parts
Slide41Question #18
An order for 6 L of 0.9% sodium chloride solution is to be prepared from 23.4% concentrated
NaCl
solution and sterile water for injection. How many mL of each should be used?
Slide42Answer #18
An order for 6 L of 0.9% sodium chloride solution is to be prepared from 23.4% concentrated
NaCl
solution and sterile water for injection. How many mL of each should be used?
23.4
0.9
0.9
0
22.5
= 23.4 total parts