Lab 11 Flashcards by amanda kastel

Suppositories are _____ dosage forms. where are they inserted

solid dosage forms inserted into body orifices (rectum, vagina, and urethra)

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how is the shape of suppositories designed/molded?

so that it can be easily inserted and retained in the intended orifice

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do suppositories exhibit local or systemic effects?

can be local and can be systemic. effects produced upon melting/dissolving

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name some types of drugs that are formulated as suppositories for LOCAL effects (give 4 examples)

antiseptics
anti-infectives
astringents

also used for local action in lower GI tract and the genitourinary system

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give an example of when a suppository would be used over oral administration

when the drug cannot reach the target sight after oral administration due to first pass effects (liver metabolism) or is destroyed by gastric or intestinal pH/enzymes

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when are suppositories used for systemic action?

when the pt can’t swallow (is unconscious/vomiting/seizures) or has GI disorders

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name 2 examples of types of drugs that are used in suppositories for systemic action

analgesics for pain relief
anti-emetics for vomiting

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the drug is mixed with __ for molding

a suitable suppository base

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how are suppository bases classified

into 3 types:

-fatty or oleaginous
-water soluble or water miscible
-misc base

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give an example of a fatty/oleaginous base

cocoa butter

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give an example of a water soluble/water miscible base

PEG (polyethylene glycol)

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give an example of a miscellaneous base

blends of fatty and water soluble/water miscible bases

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give 3 advantages of fatty/oleaginous bases (cocoa butter)

-non-irritating to sensitive tissues

-less reactive and has less stability issues

-contains surfactants/emulsifying agents that enhance the release of hydrophobic drugs

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what type of base is preferred for rectal suppositories?

fatty/oleaginous base

it’s non-irritating to sensitive tissues

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name 4 disadvantages of fatty/oleaginous base suppositories

-may leak out of body cavity – not good choice for vaginal and urethral

-melting point may be lowered by adding other components/drugs. therefore, must be stored in fridge/controlled temp

-poor release of hydrophobic drugs (unless emulsifying agent/surfactant is added)

-may manifest polymorphism

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which type of suppository base is preferred for vaginal and urethral use?

water soluble/water miscible bases (PEG bases)

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name 3 advantages of water soluble/water miscible bases

-does not leak

-may not melt at fairly warm room temp

-more reliable release of hydrophobic drugs because it slowly DISSOLVES into the aqueous secretions of the body cavity

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which base provides a more reliable release of hydrophobic drugs and why

water soluble/water miscible base slowly DISSOLVES in the aqueous secretions

fatty/oleaginous MELTS and can provide hydrophobic drug release only by the addition of an emulsifying agent or surfactant

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name 3 disadvantages of water miscible bases (PEG)

-may cause stinging or burning. defecating reflex when used rectally (that’s why oleaginous/fatty base is preferred for rectal)

-must be dipped into water b4 use if it contains less than 20% water

-may cause chemical incompatibility with some drugs

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the release of drugs from suppositories is dependent on what (3)

the nature of the suppository base

the use of surfactants or other additives

the solubility of the drug in the suppository base

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for effectiveness, when should the drug be released from the suppository

should be released before the suppository is expelled from the patient (by defecation or urination)

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true or false

drug solubility is an important factor for drug release

true

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what kind of bases have a better release for water soluble drugs?

oleaginous bases

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water soluble and water miscible bases are preferred for what kind of drugs

water insoluble drugs

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true or false the suppository base used should be therapeutically inert and exhibit polymorphism

FALSE therapeutically inert and NOT exhibit polymorphism

why must a suppository base NOT exhibit polymorphism

bc polymorphism can alter the melting properties of the base (fatty/oleaginous base may exhibit polymorphism)

true or false the drug must be stable and compatible in the base

true

the base must be non ___, non____, and non____

non toxic non sensitizing non irritating

true or false suppository bases must be free of objectionable odor

true

explain the state of matter that suppository bases should be

should be SOLID at room temp but melt/soften/dissolve at body temp

true or false the drug release from suppositories is more predictable than oral and parenteral drugs

FALSE drug release from suppositories is less predictable bc there is no environment for absorption in the rectum

which has more surface area for absorption and why -- the rectum or the small intestine

the small intestine has more because it has villi

in suppositories, how much of the drug bypasses 1st pass metabolism? how much is actually absorbed rectally?

2/3 of the drug bypasses 1st pass metabolism only 1/3 is absorbed rectally is taken to the liver via hepatic portal system and may be metabolized before reaching the site of action (1st pass)

true or false rectal fluids have POOR buffering capacity

true

rectal _______ may affect drug absorption and stability

what is the acetaminophen density factor for PEG

2.5

how much PEG is displaced by 200mg of acetaminophen? also give the formula

2.5 = 200/x x = 80mg density factor = mg drug/weight of base displaced

what is an important step when considering the amount of PEG base + acetaminophen to use in preparing suppositories

prepare for 1 extra suppository (x+1)

give the formula to calculate density factor

DF = weight of drug/weight of base displaced

what is ALWAYS the density factor when the drug has the same density as the base? what does this mean?

DF = 1 this means that the drug will replace an equal weight of the base. therefore, the weight of the drug can be directly subtracted from the weight of the base

when the drug has a higher or lower density than the base, what is the density factor

either >1 or < 1 respectively

true or false when the drug has a higher density than the base, the DF will be less than 1

false -- greater than 1

to obtain the weight of the base required for preparation, what must be done?

the weight of base displaced by volume of the drug must be calculated and then substracted from the weight of a blank suppository (without drug)

true or false suppository molds have a fixed volume

TRUE

suppository molds are formulated by ____ since they have a fixed volume

weight

the _____ displaces a volume of the __

drug displaces a volume of the base

density of cocoa butter = 0.86g/mL 12mL of cocoa butter required to fill a suppository mold the drug (500mg) in the formula takes up 2.8mL of the mold CALCULATE THE DENSITY FACTOR HOW MANY GRAMS OF COCOA BUTTER ARE REQUIRED TO PREPARE 4 SUPPOSITORIES

12mL-2.8mL = 9.2mL remaining 9.2mL * 0.86g/mL = 7.91g of cocoa butter

relative density factor is used to calculate what

the quantity of base displaced when the density factor for the required base is KNOWN and the density factor for 2 other bases is known

give the formula for relative density factor

RDF = density of base )used in preparation) / density of base with KNOWN drug density factor

the density factors for many drugs and bases in ____ is known

cocoa butter

name 2 preparation techniques for suppositories

fusion method double casting

what method of preparing suppositories is generally used in small-scale manufacture

fusion method

explain how the fusion method for preparing suppositories works

the base is melted drug is uniformly dispersed or dissolved in the base melted mixture is poured into the mold suppository is removed once it is solidified

what is the usual size for an adult rectal suppository

~2g

the ingredients for suppositores are usually given using _____ but are poured into a mold of specified ____

weight volume

true or false the densities of the drug and the base are the same

false - they may differ

the quantity of base used must be adjusted for what?

the volume of base that will be displaced by the drug

explain the double casting method of preparing suppositories

suppositories are manually casted/molded and remelted to a uniformly dispersed suppository base can be used instead of the calculation method

suppositories must be inspected for quality before packaging and dispensing they must be observed for what?

excessive hardening or softening, and for the uniformity of drug distribution smooth even shape with no indentation at the top or the sides

what USP chapter recommends the beyond use date of suppositories what do they state?

USP 795 25% of the time remaining until the product's exp date OR 6 months (whichever is earlier)

when are shorter beyond use times than those used in 795 recommended?

when the stability of the product is a concern based on the manufacturing process, etc

how must suppositories be stored

protected from heat stored under refrigeration (NOT frozen)

which suppositories must be stored in airtight containers and why?

PEG suppositories bc they are hygroscopic

true or false cocoa butter suppositories do not require refrigeration

FALSE PEG suppositories do not require refrigeration