Rectal and vaginal solid dosage forms

Question 1

Fate of drug administered by superior haemorrhoidal vein

Answer 1

Drains into portal system, first pass metabolism

Question 2

Fate of drug administered into middle and inferior haemorrhoidal veins

Answer 2

Drain directly into venous system, no first pass metabolism

Question 3

Local effects of the rectal route

Answer 3

Relieve constipation, increase water content in bowel, relieve pain and itching of haemorrhoids, local anaesthetics and vasoconstrictors

Question 4

Systemic effects of rectal route

Answer 4

Pain relief, anti nauseants, anti inflammatories

Question 5

Advantages of the rectal route

Answer 5

Suitable when oral route not possible, less invasive than parenteral, can avoid 1st pass metabolism

Question 6

Disadvantages of rectal route

Answer 6

Absorption unpredictable, less convenient, low acceptability by patients

Question 7

Why are suppositories shaped a certain way

Answer 7

Tapered at one end to aid insertion, wider at other end to aid retention

Question 8

How do suppositories work

Answer 8

Solid at storage temp, melt or dissolve in rectum to release drug

Question 9

How do lipophilic bases work

Answer 9

Melt to release drug

Question 10

How do hydrophilic bases work

Answer 10

Dissolve to release drug

Question 11

Release rate of lipophilic drug in lipophilic base

Answer 11

Slow

Question 12

Release rate of hydrophilic drug in hydrophilic base

Answer 12

Moderate

Question 13

Release rate of hydrophilic drug in lipophilic base

Answer 13

Rapid

Question 14

Main types of suppository bases

Answer 14

Fatty (oleaginous) and water miscible

Question 15

Types of fatty (oleaginous) bases

Answer 15

Theobroma oil, hard fat

Question 16

Heating of cocoa butter

Answer 16

If melt base keep under 36 degrees and allow to solidify will slowly form beta form (most stable), if heat above 36 degrees allow to cool, form other polymorphic forms, take several days to set

Question 17

Disadvantage of synthetic hard fat base

Answer 17

Less viscous than theobroma oil on melting, uneven distribution of drug in base

Question 18

How do water soluble/miscible bases work

Answer 18

Dissolve in rectal fluids to release drugs

Question 19

Types of water soluble/miscible bases

Answer 19

Glycero-gelatin base, PEGs

Question 20

Other excipients in suppository formulations

Answer 20

Surface active agents, agents to reduce hygroscopicity, agents to manipulate MP of base

Question 21

Large scale manufacture of suppositories

Answer 21

Preparation heated in vessel, molten material dosed into mold, cooled, mechanically removed, automatically packaged into final container

Question 22

Benefits of using the vaginal route

Answer 22

Abundant blood vasculature, local and systemic effects, first pass metabolism can be avoided

Question 23

Benefits of vaginal tablets

Answer 23

Stable, less messy to handle, disintegrate in vagina and release drug, offer advantage of manufacture and insert

Question 24

Factors to consider with vaginal rings

Answer 24

Mostly flexible and non irritating, normally non-biodegradable, not messy to use, release predetermined amount of drug per day for extended period, must be removed after use