Pessaries, Suppositories, & Displacement Values
The displacement value is the weight of the base displaced by 1g of drug powder.
• Determine total weight of one pessary or suppository.
• Determine weight of drug per unit.
• Obtain displacement value for the drug powder.
• Calculate displaced base weight
• Calculate base weight per unit
• Multiply number of units to find the total base and drug needed.
1) Prepare 20 pessaries weighing 3 g each, with 0.25 g drug (DV 0.10). Calculate base needed.
2) Prepare 15 suppositories weighing 2.5 g each, 0.1 g drug (DV 0.13). Calculate base required.
3) You want 10 pessaries of 4 g each, with 0.3 g drug (DV 0.12). Calculate total drug and base needed.
4) A suppository contains 0.2 g drug, total weight 3 g, DV 0.18. Find base weight.
5) You want to make 12 suppositories, each 3 g, containing 0.15 g drug (DV 0.15). Calculate total drug and base
needed.
6) You need to prepare 25 pessaries, each weighing 3.5 g and containing 0.35 g of a drug with a displacement value
of 0.18. Calculate the total weight of base required and total drug needed.
7) A formulation requires 15 pessaries of 4 g each with 0.4 g drug per pessary. The displacement value of the drug is
0.22. Calculate how much base and drug powder are needed.
8) You have 40 g of base and want to prepare pessaries weighing 3.8 g each containing 0.25 g drug with
displacement value 0.15. Calculate the maximum number of pessaries you can prepare and the total drug
required.
9) A batch of 20 pessaries weighing 5 g each contains 0.5 g drug with displacement value 0.2. Calculate the weight
of base needed per pessary and total base for the batch.
10) You want to prepare 18 suppositories weighing 3 g each, containing 0.35 g drug with displacement value 0.14.
Calculate total base and drug powder needed.
11) A suppository contains 0.25 g drug and weighs 3.2 g. The displacement value is 0.21. Calculate the weight of base
per suppository and total base required for 25 suppositories.
12) Determine the displacement value of a drug powder if 0.4 g drug displaces 0.06 g base in a suppository
formulation with drug content 0.4 g and total weight 3.5 g.
13) You must prepare 15 suppositories, each weighing 3.2 g and containing 0.42 g of drug A (displacement value
0.16) and 0.10 g of drug B (displacement value 0.12).
a) Total weight of drug A and drug B required
The displacement value is the weight of the base displaced by 1g of drug powder.
• Determine total weight of one pessary or suppository.
• Determine weight of drug per unit.
• Obtain displacement value for the drug powder.
• Calculate displaced base weight
• Calculate base weight per unit
• Multiply number of units to find the total base and drug needed.
1) Prepare 20 pessaries weighing 3 g each, with 0.25 g drug (DV 0.10). Calculate base needed.
2) Prepare 15 suppositories weighing 2.5 g each, 0.1 g drug (DV 0.13). Calculate base required.
3) You want 10 pessaries of 4 g each, with 0.3 g drug (DV 0.12). Calculate total drug and base needed.
4) A suppository contains 0.2 g drug, total weight 3 g, DV 0.18. Find base weight.
5) You want to make 12 suppositories, each 3 g, containing 0.15 g drug (DV 0.15). Calculate total drug and base
needed.
6) You need to prepare 25 pessaries, each weighing 3.5 g and containing 0.35 g of a drug with a displacement value
of 0.18. Calculate the total weight of base required and total drug needed.
7) A formulation requires 15 pessaries of 4 g each with 0.4 g drug per pessary. The displacement value of the drug is
0.22. Calculate how much base and drug powder are needed.
8) You have 40 g of base and want to prepare pessaries weighing 3.8 g each containing 0.25 g drug with
displacement value 0.15. Calculate the maximum number of pessaries you can prepare and the total drug
required.
9) A batch of 20 pessaries weighing 5 g each contains 0.5 g drug with displacement value 0.2. Calculate the weight
of base needed per pessary and total base for the batch.
10) You want to prepare 18 suppositories weighing 3 g each, containing 0.35 g drug with displacement value 0.14.
Calculate total base and drug powder needed.
11) A suppository contains 0.25 g drug and weighs 3.2 g. The displacement value is 0.21. Calculate the weight of base
per suppository and total base required for 25 suppositories.
12) Determine the displacement value of a drug powder if 0.4 g drug displaces 0.06 g base in a suppository
formulation with drug content 0.4 g and total weight 3.5 g.
13) You must prepare 15 suppositories, each weighing 3.2 g and containing 0.42 g of drug A (displacement value
0.16) and 0.10 g of drug B (displacement value 0.12).
a) Total weight of drug A and drug B required
