Lecture 7: suppositories

Question 1

When are suppositories a reasonable dosage form?

Answer 1

medicated solid, various weights and shapes, intended for insertion into body cavities: rectal, vaginal, urethral use that melts and dissolves at body temperature,
A good alternative for NPO patients avoiding IV access

Question 2

Why are compounded suppositories often seen as a “last resort”?

Answer 2

1. difficult to comopund
2. unpredictable absorption
3. avoid when narrow therapeutic window (hard to dose)

Question 3

What are characteristics of an ideal suppository base?

Answer 3

1. chemically & phyiscally stable
2. nonreactive and stable w/ drugs and auxillary agents
3. aesthetically pleasing
4. melts and dissolves in the intended body cavity
5. nontoxic, nonirittating
6. nonbinding w/ drugs
7. viscous enough for drug suspension
8. thin enough to pour into mold
9. shrinks on cooling to easily release from molds

Question 4

Types of suppository bases (2)

Answer 4

1. Oleaginous (fatty)
2. Water soluble/miscible

Question 5

Oleaginous base

Answer 5

MELT
cocao butter
fattibase
Drug absorption affected:
1. oil soluble = slow absorptoin (remains in fattibase)
2. water soluble = rapid absorption

Question 6

Water miscible base

Answer 6

DISSOLVE
Polyethylene glycol (PEG)

Drug absorption affected:
1. oil soluble = moderate absorptoin
2. water soluble = moderate absorption

Question 7

Suppository prepration methods (3)

Answer 7

1. hand rolling
2. compression molding
3. fusion molding

Question 8

hand rolling

Answer 8

less equipment
more skill/practice

Question 9

fusion molding

Answer 9

melted, poured, cooled
requires density calculations and mold calibrations

Question 10

Density factor (DF)

Answer 10

Determines how much base will be displaced by drug

ratio of a unit mass of drug powder to the amount of suppository base displaced by the powder
* drug and base specific
* not mold specific
Drug mass: suppository displaced
ex: if 2g of drug = X mL displacement

Question 11

When is density factor needed to be calculated?

Answer 11

DF only needed when:
1. drug has a quantity dose and used for systemic effect (500mg APAP in 1 suppository, systemic pain)
2. quantity of drug is a relative significant portion of the dosage form (500mg of drug in 2g base)
3. when density difference exists between the base and drug
(density of drug and base not the same)

some can look up, other times calculated

Question 12

Mold calibration

Answer 12

the average mass of one pure base suppository cast in mold
* mold and base specific
* not drug specific
Cocoa butter weights different amount than PEG made from the same mold

you are JUST working with the base: mold, base specific

Question 13

What if the drug source for a suppository is a suspension?

Answer 13

1. levigation/geometric necessary
2. constant stirring during pour
3. pour at cool temperature to increase viscosity

Question 14

Factors to consider for mold lubricating agent

Answer 14

should not be miscible w/ suppository base
1. cocao butter/fattibase –> green soap
2. PEG and glycerin –> mineral oil

Question 15

Do we ever use water in suppository compounding?

Answer 15

NO, avoid water
1. supports bacterial/fungal growth
2. increases degredation of drugs
3. accelerates oxidiation of fats
4. contributes to brittleness

Question 16

Counseling suppositories

Answer 16

1. proper technique education
2. REMOVE FOIL/wrapper
3. proper storage temperature