Section 7: Suppositories

Question 1

What are suppositories?

Answer 1

Solid dose forms for insertion into body orifices where they melt, soften, or dissolve releasing drug for local or systemic effect

Question 2

What are suppositories commonly used for?

Answer 2

Rectal or vaginal insertion

Question 3

What is special about the size and shape of suppositories?

Answer 3

Easy to insert and remain in place after insertion

Question 4

What is usually the shape of a rectal suppository for adults?

Answer 4

Bullet-shaped

Question 5

What is usually the weight of a rectal suppository for adults?

Answer 5

2 g

Question 6

What is usually the shape of a rectal suppository for children?

Answer 6

Small and more cylindrical

Question 7

What is usually the shape of a vaginal suppository?

Answer 7

Ovoid/egg shape

Question 8

What is usually the weight of a vaginal suppository?

Answer 8

5 g

Question 9

What happens to a suppository after it is inserted?

Answer 9

It melts, softens, or dissolves and medication is released to surrounding tissues

Question 10

What are rectal suppositories for local effect used to treat?

Answer 10

Pain, inflammation, and itchiness associated with hemorrhoids or other anal-rectal conditions

Question 11

What do rectal suppositories for local effect usually contain?

Answer 11

Local anesthetics, vasoconstrictors, astringents, analgesics, emollients, and protective agents

Question 12

Why are emollients often found in rectal suppositories?

Answer 12

Make things softer

Question 13

What is found in rectal suppositories that treat constipation and why?

Answer 13

Glycerin because it has a local irritating effect and lubricates

Question 14

True or false: some suppositories contain laxative agents

Answer 14

True

Question 15

What are vaginal suppositories usually used for?

Answer 15

Local effect, often for an infection

Question 16

What are less common use of vaginal suppositories?

Answer 16

Contraceptive effects, antiseptics for hygiene, or local delivery of agent to treat infection due to yeast

Question 17

What are some common systemic conditions that can be treated with suppositories?

Answer 17

• Nausea and vomiting
• Migraines
• Analgesics
• Tranquilizers

Question 18

What are 3 advantages for suppository systemic use?

Answer 18

1) Bypasses GI tract and first-pass metabolism
2) Drugs irritating to stomach can be given this way
3) Used for patients unable to use oral route

Question 19

What is a disadvantage to suppository use?

Answer 19

Absorption is erratic with inter-patient variability

Question 20

What are 2 factors that affect drug absorption for suppositories?

Answer 20

1) Physiological

2) Physicochemical

Question 21

How long is the adult rectum and what does it contain?

Answer 21

• 20 cm long

- Contains 2-3 mL of inert mucous fluid

Question 22

Why is absorption efficient in the rectum?

Answer 22

Large surface area and extensive blood and lymphatic vascularization

Question 23

What conditions can affect absorption in the rectum?

Answer 23

Inflammation, diarrhea, tissue dehydration, and presence of tumours or polyps

Question 24

What picks up drugs that have been absorbed by the rectum?

Answer 24

Blood and lymphatic vessels

Question 25

What is the pH of an empty colon?

Answer 25

Neutral, with little buffer capacity

Question 26

True or false: the ionic form of the drug will be affected when it is administered via a suppository

Answer 26

False, the ionic form will not be affected

Question 27

What physicochemical properties affect absorption of suppositories?

Answer 27

- Solubility - Partition coefficient - Particle size

Question 28

What properties of the base of a suppository affect absorption?

Answer 28

- If it melts or dissolves | - If it is hydrophilic/hydrophobic

Question 29

What MUST a suppository base to?

Answer 29

Must remain solid at room temperature but soften, melt, or dissolve at body temperature

Question 30

What is the best suppository base for fat-soluble drugs and why?

Answer 30

Cocoa butter because it melts readily at body temperature but is immiscible with colonic fluid

Question 31

What is the best suppository base for lipid-soluble drugs?

Answer 31

Water soluble polyethylene glycol

Question 32

What are the 2 types of suppository bases?

Answer 32

1) Oleaginous and water soluble | 2) Miscible

Question 33

What is generally used in oleaginous bases?

Answer 33

Cocoa butter

Question 34

At what temperature range does triglyceride melt?

Answer 34

30-36 C

Question 35

What happens when cocoa butter is heated?

Answer 35

It forms polymorphs

Question 36

What happens when cocoa butter is heated beyond its melting point?

Answer 36

It forms alpha polymorphs, which is liquid at room temperature

Question 37

What material can be added to cocoa butter to lower its melting point?

Answer 37

Phenol

Question 38

What is an advantage to using semi-synthetic oleaginous bases?

Answer 38

Do not form low temperature melting polymorphs

Question 39

What are 2 examples of semi-synthetic oleaginous bases and what are they made of?

Answer 39

1) Fattibase -- triglycerides from palm and coconut oil | 2) Witepsol -- triglycerides of C12-C18 saturated fatty acids

Question 40

What type of oleaginous bases are good for rectal irritation and why?

Answer 40

Semi-synthetic because it had soothing emollient properties

Question 41

What are 2 examples of water soluble and miscible bases?

Answer 41

1) Polyethylene glycols | 2) Glycerinated gelatin

Question 42

What is unique about polyethylene glycol?

Answer 42

Comes in a variety of molecular weights, ranging from 200-8000, with lower values being liquid

Question 43

What does a higher value PEG correspond with?

Answer 43

Higher melting point

Question 44

Normally, is one PEG used or is a combination used and why?

Answer 44

A combination is used so they can fuse and incorporate the medication

Question 45

How does a PEG mixture release medication?

Answer 45

Slowly dissolving

Question 46

PEG is hydroscopic. What does this mean?

Answer 46

It needs to be protected from moisture; but must be moistened just prior to use otherwise a stinging sensation will ocur

Question 47

What type of base is usually used for vaginal inserts?

Answer 47

Glycerinated gelatin

Question 48

What does glycerinated gelatin consist of?

Answer 48

20% gelatin, 70% glycerin, and 10% water

Question 49

How does glycerinated gelatin release medication?

Answer 49

Slow, and through softening and dissolution

Question 50

True or false: glycerinated gelatin is not miscible with vaginal secretions

Answer 50

False, the two are miscible

Question 51

What is glycerin base composed of?

Answer 51

85% glycerin, 9.5% sodium stearate, 5.5% water

Question 52

What are the 3 ways to prepare a suppository?

Answer 52

1) Molding 2) Compression 3) Hand rolling and shaping

Question 53

What is the most common method of suppository preparation?

Answer 53

Molding

Question 54

True or false: when preparing a suppository, the least possible amount of heat is used

Answer 54

True

Question 55

True or false: when preparing a suppository, it is best to melt the base right on the hot plate

Answer 55

False, it is best to melt in a water bath

Question 56

How are medicinal substances incorporated when preparing a suppository?

Answer 56

- Mix with some molten base using spatulation | - Stir into molten base and remove from heat

Question 57

When making a suppository, what ingredients are the last to be added?

Answer 57

Labile or volatile ingredients

Question 58

What are 2 tips to use when pouring suppository mixture into molds?

Answer 58

1) Stir while pouring just above congealing temperature to prevent material from settling in tip 2) Pour small excess to allow for contraction

Question 59

_____ molds should be lubricated prior to use

Answer 59

Metal

Question 60

When should excess material be scraped away when preparing suppositories?

Answer 60

After completely cooled, but before opening the mold

Question 61

Why should excess mixture be prepared when making suppositories?

Answer 61

To allow for losses

Question 62

What are the 2 types of suppository molds?

Answer 62

1) Metal | 2) Plastic

Question 63

How should suppositories containing glycerin be stored?

Answer 63

- In glass or otherwise protected from moisture | - May need refrigeration

Question 64

How should suppositories containing PEG be stored?

Answer 64

Keep away from moisture

Question 65

How should suppositories containing cocoa butter be stored?

Answer 65

Individually wrapped to prevent adhesion

Question 66

What should the patient be counselled on when using suppositories (4 points)?

Answer 66

1) Ensure all wrapping is removed prior to use 2) Tip inserted first 3) If half suppository prescribed, cu length-wise 4) Dip PEG or glycerin based products in water prior to use to avoid burning sensation

Question 67

What are 3 common calculations that need to be done when preparing suppositories?

Answer 67

1) Calibrations 2) Base displaced by medication 3) Amount of base and medication needed

Question 68

What is an important note about base displaced by medication calculations?

Answer 68

Suppositories with a mass of 2 g and a drug load less than 100 mg, the mass of base being displaced is generally insignificant and doesn't need to be considered

Question 69

Can tablets be used as the drug source for suppositories?

Answer 69

Yes, but must take into account the weight of excipients

Question 70

What is density factor usually for?

Answer 70

Cocoa butter

Question 71

What does density factor allow for?

Answer 71

Calculation of how much base will be displaced by drug

Question 72

What is the formula for density factor?

Answer 72

df = weight of drug / weight of base displaced