Suppositories Flashcards

1
Q

what are suppositories?

A

solid dosage forms intended for insertion into body orifices where they melt, soften, or dissolve and exert local or systemic effects

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2
Q

what are the most common forms that suppositories are used?

A

rectally

vaginally

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3
Q

how is shape important with suppositories?

A

need to be able to be inserted easily into the orifice but stay in place once inserted for the appropriate amount of time

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4
Q

how are rectal suppositories usually inserted?

A

using the fingers

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5
Q

when would you need an application appliance for vaginal suppositories?

A

when the insert needs to be inserted high in the tract

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6
Q

what is the usual shape of rectal suppositories?

A

bullet/torpedo shaped

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7
Q

what is the typical weight for adult rectal suppositories?

A

2g

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8
Q

what is the typical weight and size of vaginal suppositories?

A

mass: 5g

cone-shaped or rounded

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9
Q

what are rectal suppositories usually used for (local effect)?

A

treat pain, inflammation, and itchiness associated with hemorrhoids or other anal/rectal conditions
could also treat constipation

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10
Q

what kind of excipient functions would be found in rectal suppositories for local effect?

A
local anesthetics
vasoconstrictor
astringents
analgesics
emollients
protective agents
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11
Q

what agent in suppositories can help treat constipation? how?

A

glycerin - mild local irritating effect and lubricating effect

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12
Q

what are vaginal inserts typically used for?

A

contraception
antiseptics for feminine hygiene
local delivery of agents to treat infections (ex: yeast, protozoa)

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13
Q

what are some systemic uses of suppositories?

A

treat nausea/vomiting

migraine headaches

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14
Q

what are 3 advantages to rectal route for systemic drug delivery?

A

1) the drugs avoid the pH and enzymatic activity of the stomach and intestine and avoids first-pass hepatic metabolism
2) drugs irritating to the stomach may be given this way
3) useful patients who are unable to take medication by mouth for various reasons including vomiting

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15
Q

what are 2 factors that can affect drug absorption?

A

physiologic factors

physicochemical factors

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16
Q

how much inert mucous fluid does the rectum contain when empty?

A

2-3mL

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17
Q

what causes efficient drug absorption in the rectum (physiologically)?

A

great deal of blood and lymphatic vascularization in the tissue as well as large surface area

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18
Q

how will emptying of colon increase drug absorption?

A

there will be more contact between released drug and the colon tissues

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19
Q

what conditions could affect rectal drug absorption?

A

diarrhea
inflammation
tissue dehydration
obstruction by tumours/polyps

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20
Q

why is the drug not affected by the environment of the colon?

A

empty colon has neutral pH and little buffer capacity

ionic form in which the drug is administered will not be affected by the environment

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21
Q

what 3 properties of drugs affect absorption?

A

solubility
partition coefficient
particle size

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22
Q

what are 3 properties of suppository bases that affects absorption?

A

whether it dissolves/melts
whether its hydrophilic/phobic
how it interacts with and releases the drug

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23
Q

what is an important characteristic that make a good suppository base?

A

remain solid at room temp but soften, melt, or dissolve at body temp

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24
Q

how is cocoa butter as a suppository base?

A

melts readily at room temp, but is immiscible with body fluids so fat soluble drugs remain in oil rather then enter aqueous body fluids

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25
Q

what substance tends to release fat soluble drugs better?

A

polyethylene glycol

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26
Q

when is cocoa butter good to use? why?

A

for inflamed tissues

it has a soothing, emollient action

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27
Q

what are the two classifications of suppository bases?

A

oleaginous

water-soluble/miscible

28
Q

what is cocoa butter like at room temp?

A

yellowish white solid with a faint chocolate-like odor

29
Q

what is cocoa butter, chemically speaking?

A

a triglyceride that melts at 30-36°C

30
Q

cocoa butter forms polymorphs. what polymorph is formed when cocoa butter is heated to temperatures way above its MP then cooled quickly?

A

alpha polymorph

31
Q

what is significant about the alpha polymorph?

A

has a much lower MP than the original stable beta polymorph and will be a liquid or semi-solid at room temp

32
Q

how do you properly melt cocoa butter?

A

carefully over a water bath then cooled slowly so beta polymorph will remain

33
Q

what do phenol or chloral hydrate do to cocoa butter? how do you counteract this?

A

lower the MP

beeswax (4%) added to compensate

34
Q

why is appropriate volume of beeswax added important?

A

so the suppository will not be too hard and not melt at body temp

35
Q

what are other examples of oleaginous suppository bases?

A

fattibase

witepsol

36
Q

what types of molecules are found in water-soluble/miscible bases?

A
polyethylene glycols
glycerinated gelatin (20% gelatin, 70% glycerin, 10% water)
37
Q

what is the MW range for polyethylene glycols? why is this significant?

A

300-8000
low MW - liquids
high MW - solids
MP increases with increasing MW

38
Q

how do water-soluble/miscible bases release drugs into the body?

A

by dissolution rather than melting at body temp

release is slower than cocoa butter

39
Q

what are some pros to water-soluble/miscible bases?

A

1) have higher MP so won’t melt on fingers during insertion

2) miscible with body fluids, meaning they do not tend to leak from the rectum

40
Q

how should you store and use polyethylene glycols?

A

store away from moisture (slightly hydroscopic)

dip in water before use otherwise they will draw water from the tissues and cause a stinging sensation

41
Q

what are glycerinated gelatin bases typically used for?

A

vaginal suppositories

42
Q

how do glycerinated gelatin bases release drugs into the body?

A

softening and slow dissolution so release is slower

43
Q

what is something you need to do specifically with glycerinated gelatin bases? why?

A

protect from moisture since glycerin is hydroscopic

44
Q

what are the components of a glycerin base?

A

85% glycerin

  1. 5% sodium stearate
  2. 5% water
45
Q

what are the 3 general methods of preparing suppositories?

A

molding
compression
hand rolling and shaping

46
Q

what are the general steps involved in making a suppository using the molding method?

A

1) melting the base
2) incorporating the medication
3) pouring the melt into the molds
4) allowing them to set
5) removal and packaging

47
Q

what is the best method to melt the base?

A

water bath with the least possible amount of heat used

48
Q

how are the medications introduced into the base?

A

mixed with a small amount of molten base using spatulation and then stir this into the molten base which has been allowed to start cooling

49
Q

when should volatile/hat-labile substances be incorporated into the suppository?

A

just before the congealing point of the base is reached

50
Q

what should you do if pouring a melt containing suspended materials into the mold cavities?

A

stir during the pouring process to ensure homogeneity

51
Q

how do you properly fill the mold cavities?

A

small excess of the melt should be placed in each cavity since they usually contract when cooling
scrape excess away when they harden

52
Q

what types of molds are usually available?

A

metal ones - repeated use

plastic molds for one time use

53
Q

what is a pro about plastic molds?

A

provide a protective shell around the suppository

need to tell pt to remove plastic shell prior to use

54
Q

how should you store glycerin containing suppositories?

A

in a tightly-closed glass containers to protect from moisture

55
Q

how should you store cocoa based products?

A

individually wrapped/separated to prevent contact and adhesion
store in fridge

56
Q

how should you store polyethylene glycol based products?

A

protect from moisture

store at 20-25°C

57
Q

what are some things you should advise the patient on for proper suppository use?

A

1) remove packaging before insertion
2) educate on shape of suppository and which end goes in first
3) proper storage
4) if half a suppository is to be used, say to cut it length wise with a sharp knife
5) dip glycerin/polyethylene glycol containing suppositories in water first to avoid burning

58
Q

what is the first step in suppository calculations?

A

fill all the cavities in the mold with melted base, allow to harden, trim and weigh. determine the total and average suppository wt

59
Q

what is the second step in suppository calculations?

A

divide the total and average suppository weights by the density of the base to determine the volume capacity of the mold and the individual cavities

60
Q

what is the 3rd step in suppository calculations?

A

weigh the meds for preparation of a single suppository and mix with a portion of the melted base insufficient to fill one cavity. this is known from the previous calibration

61
Q

what is the 4th step in suppository calculations?

A

pour the drug-base mix into a cavity then add sufficient melted base to fill the cavity. allow the suppository to harden, trim, and then weight the suppository.

62
Q

what is the fifth step for suppository calculations?

A

the weight of dbase for one suppository is determined by subtracting the weight of the drug from the total weight

63
Q

what is the 6th step for suppository calculations?

A

the weights of drug and base required to prepare the Rx number of suppositories can be determined by multiplying the amounts for a single suppository

64
Q

what is the density factor (df) equation?

A

density factor = wt of rug/wt of base displaced

65
Q

what are the units for df?

A

none, shit’s unitless