Unit 2 Section A Answers

1. When can a solution be termed isotonic? A solution is termed isotonic when it has the same osmotic pressure as that of body fluids such as blood or tears. This prevents water movement across cell membranes, avoiding cell shrinkage or swelling. 2. Determine 80% v/v alcohol in terms of proof spirit. 100 proof spirit = 57.1% v/v alcohol. Proof strength = (80 ÷ 57.1) × 100 = 140.1° proof spirit. 3. Define allegation. Allegation is a method used in pharmacy for calculating the ratio in which two or more ingredients of different strengths are to be mixed to obtain a desired strength. 4. Write the use of geometric dilution. Geometric dilution is used to ensure uniform mixing of a small amount of potent drug with a large amount of diluent by gradually mixing equal proportions in geometric sequence. 5. How can we calculate pediatric dose? Pediatric dose can be calculated using formulas such as: Young’s rule: (Age / (Age + 12)) × Adult dose Clark’s rule: (Weight in lbs / 150) × Adult dose Surface area method: (Child’s BSA / 1.7) × Adult dose 6. What do you understand by proof spirit? Proof spirit is an alcoholic liquid containing 57.1% v/v of ethanol at 15.5°C. It is used as a standard reference to express the strength of alcoholic preparations. 7. Calculate the dose for a child of 5 years with a surface area of 1.5 m², given the adult dose is 40 mg. Using Surface area method: Child dose = (Child’s BSA / 1.7) × Adult dose = (1.5 / 1.7) × 40 = 35.3 mg. 8. Calculate the number of tablets prepared from 5 kg of aspirin if a tablet contains 325 mg of aspirin. Total aspirin = 5 kg = 5,000,000 mg Number of tablets = 5,000,000 ÷ 325 = 15,385 tablets (approximately).


1. When can a solution be termed isotonic?
A solution is termed isotonic when it has the same osmotic pressure as that of body fluids such as blood or tears. This prevents water movement across cell membranes, avoiding cell shrinkage or swelling.

2. Determine 80% v/v alcohol in terms of proof spirit.
100 proof spirit = 57.1% v/v alcohol.
Proof strength = (80 ÷ 57.1) × 100 = 140.1° proof spirit.

3. Define allegation.
Allegation is a method used in pharmacy for calculating the ratio in which two or more ingredients of different strengths are to be mixed to obtain a desired strength.

4. Write the use of geometric dilution.
Geometric dilution is used to ensure uniform mixing of a small amount of potent drug with a large amount of diluent by gradually mixing equal proportions in geometric sequence.

5. How can we calculate pediatric dose?
Pediatric dose can be calculated using formulas such as:

Young’s rule: (Age / (Age + 12)) × Adult dose

Clark’s rule: (Weight in lbs / 150) × Adult dose

Surface area method: (Child’s BSA / 1.7) × Adult dose

6. What do you understand by proof spirit?
Proof spirit is an alcoholic liquid containing 57.1% v/v of ethanol at 15.5°C. It is used as a standard reference to express the strength of alcoholic preparations.

7. Calculate the dose for a child of 5 years with a surface area of 1.5 m², given the adult dose is 40 mg.
Using Surface area method:
Child dose = (Child’s BSA / 1.7) × Adult dose
= (1.5 / 1.7) × 40
= 35.3 mg.

8. Calculate the number of tablets prepared from 5 kg of aspirin if a tablet contains 325 mg of aspirin.
Total aspirin = 5 kg = 5,000,000 mg
Number of tablets = 5,000,000 ÷ 325 = 15,385 tablets (approximately).