A solution is 5% w/v. You need 240 mg of the drug. Draw up the volume in the syringe: what volume V is that?
Pharmacy calculations worksheet with answers
Practice exercise (made-up values, not clinical guidance). Express the ratio strength 1:10 000 as a percentage strength p (% w/v).
A solution has a ratio strength of 1:10 000. You need 0.82 mg. Draw up the volume in the 10 mL syringe: what volume V is that?
Practice exercise (made-up values, not clinical guidance). A vial of penicillin G contains 5 000 000 units. Its practice label gives three strengths (see the table). You add 8.2 mL of diluent. The prescribed dose is 2 400 000 units. What volume V do you draw up? Round to one decimal place.
Practice exercise (made-up values, not clinical guidance). You must prepare 450 mL of 15% dextrose by mixing 50% and 5% dextrose. How many mL V of the 50% solution do you need? Round to the nearest whole mL.
Practice exercise (made-up values, not clinical guidance). You must prepare 750 mL of 30% dextrose by mixing 50% and 10% dextrose. How many mL V of the 50% solution do you need? Round to the nearest whole mL.
Answer key
- 1. V = 4.8 mL
- 2. p = 0.01 %
- 3. V = 8.2 mL
- 4. V = 4.8 mL
- 5. V = 100 mL
- 6. V = 375 mL
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