pharmacy calculations: alligations

What is the purpose of using alligations in pharmacy?

To find the proportions of two solutions to obtain a desired concentration

When using alligations, where is the desired concentration placed in the grid?

Center

In the alligation grid, the higher concentration solution is placed at:

Top left

Which of the following best describes the concept of 'parts' in alligation calculations?

Proportions of each solution

In an alligation problem, if the desired concentration needs to be 10% and you have a higher concentration of 25% and lower concentration 5% solutions, what is the value of the total parts?

20 parts

You need to create 500 mL of a 10% dextrose solution in water, and you have a 25% and a 5% dextrose solution in water. How many milliliters of a 5% dextrose solution in water should be combined?

375 mL of 5% dextrose solution

You need to create 500 mL of a 10% dextrose solution in water, and you have a 25% and a 5% dextrose solution in water. How many milliliters of a 25% dextrose solution in water should be combined?

125 mL of 25% dextrose solution

If you have a 30% solution and a 10% solution, and you need to make a 20% solution, how many parts of the 30% solution are needed?

1 part

You need to prepare 120 grams of a 2.5% ointment using 1:5 parts of the base ointment to other ingredients. How many grams of the base ointment will you need?

20 grams

You need to prepare 400 mL of a 10% Dextrose in water solution. You have Dextrose 20% solution and Dextrose 5% solution. How many milliliters of each solution should you mix?

133.33 mL of the 20% solution and 266.67 mL of the 5% solution

You have 200 mL of a 30% Sodium Chloride (NaCl) solution. How many grams of NaCl are present in the solution?

60 grams

You want to make 700 mL of a 10% Hydrocortisone (Cortizone-10) solution using a 15% Hydrocortisone solution and a 5% Hydrocortisone solution. How many milliliters of the 5% solution should you use?

350 mL

Match the concept with its definition.

Alligation grid…. Visual representation of proportions

Mean strength ….Average concentration of mixed solutions

Desired concentration ….Target strength for the final mixture

Higher concentration …..Initial solution with the highest strength

What information is needed to fill in the alligation grid? (Select all that apply)

• Higher concentration

• Lower concentration

• Desired concentration

What are the benefits of using alligation in pharmacy? (Select all that apply)

• Accurate mixing of solutions

• Precision in achieving desired concentration

• Simplifies complex calculations