Lecture 19: Suppositories And Calculations

Question 0

What is a pessary?

Answer 0

They are for vaginal administration usually for local effect

Question 1

What are supppositories?

Answer 1

Solid dosage forms for insertion into the rectum where they melt or soften to allow the active ingredients to exert local or systemic effects

They are a drug delivery system where the drug is incorporated into an inert vehicle (the base)

Question 2

What are advantages of rectal administration?

Answer 2

Not exposed to degradation by gastric acid
No direct irritation to stomach
First pass metabolism is avoided
Can be used for patients who cannot swallow
Can be used for patients who are vomiting

Question 3

What is an ideal suppository base?

Answer 3

Melts at just below body temperature
Solidifies quickly after melting
Be easy to mould and remove from the mould
Be chemically stable, even when molten
Release the active ingredient readily
Be easy to handle,
Be non toxic and non irritant

Question 4

What are some examples of fatty suppository bases.

Answer 4

Natural theobroma oil

Synthetic novata B

Question 5

What are examples of water soluble and water miscible bases?

Answer 5

Gelatin bases

Macrogols

Question 6

What are suppositories manufactured in?

Answer 6

Precalibrated moulds

Question 7

What is required to calculate the amount of base displaced by the drug?

Answer 7

The displacement value (unless the density of the drug and the base are the same)

Question 8

What is the displacement value?

Answer 8

This is the number of parts, by weight of drug which displaces one part by weight of base

Question 9

What is the method of making a suppository?

Answer 9

Grate base to give accurate weight
Over water bath, heat until 2/3 is melted
For insoluble powders, place on the tile,
Add half of the molten mixture
Mix with a spatula then return it to heat to remelt if necessary
Remove it from the heat and stir until it is almost set
Overfill the moulds as it contracts on cooling
Scrape of the excess when set towards you with a warmed spatula to avoid chipping
Unscrew the mould and tap gently on the bench to open

Question 10

How are suppositories packaged?

Answer 10

Wrap individually in foil

Pack into cardboard skillet and label

Question 11

What should be on the suppository label?

Answer 11

For rectal use only
And
Do not swallow

Store in a cool place,

Expiry is 1.’onth

Question 12

What should be on the patient advice and label?

Answer 12

Unwrap and insert into the rectum