Lecture 7 - Suppositories Flashcards
(67 cards)
in suppositories, the drug is incorporated into a base which ___ or ____ at body temp to release the drug
melts or dissolves
TRUE OR FALSE
suppositories are really only used for their systemic effects
FALSE - local or systemic
local irritation, hemorrhoids
systemic hormone delivery or pain relief
vaginal suppositories are also called….
pessaries
an adult rectal suppository weighs around…..
2 grams
what is usually the shape of rectal suppositories vs vaginal
rectal are long and cylindrical with 1 tapered end
vaginal is usually globular oviform or cone shaped
around how much do vaginal suppositories typically weigh
more or less than rectal?
more than rectal - around 5g
uses of vaginal suppositories
hormone delivery
birth control
combat infection
restore vagina lmucosa to normal state
major advantages of suppositories***
NO pH degradation or enzymatic degradation of the drug (like in the gut)
very limited 1st pass effect
drugs that irritate the stomach can be delivered this wat to bypass the stomach
what is the approximate rectal pH and what is the advantage of this***
around 6.8
drugs that are degraded by low pH in the stomach thus won’t be affected by rectal administration
true or false
if a drug is susceptible to degradation in acidic environment, rectal suppositories are not a good chouce
false - they are
rectal pH is close to neutral at 6.8
major issues of suppositories*****
UNPREDICTABLE ABSORPTION - results can vary from patient to patient
can be slow and incomplete absoroption
mucosal irritation
give 3 reasons why absorption from suppositories is unpredictable***
contents of the colon
placement of suppository
GI probelms
which has larger surface area for absorption and what does this mean - GI or rectum***
GI
therefore, absorption may be incomplete and slow when things given rectally
true or false
suppositories do not require special storage requirements
FALSE - they do – this is disadvantage
the rectum is the terminal portion of the_____
large intestine
***volume of the rectal fluid
1-3mL
TRUE OR FALSE
the rectum has high buffer capacity
what is significance
false - low buffer capacity
therefore, the drug inserted must be extremely close to neutral
if basic, can turn fluid alkaline by adding a base which can cause irritation
what position are rectal suppositories supposed to be inserted and why – explainnnn**
in the LOWER AND MIDDLE VEINS
this is bc it drains directly into the inferior vena cava and bypasses the liver and first pass effects to go DIRECTLY into circulation
upper rectal vein drains directly into hepatic portal vein – goes right to liver and subject to hepatic metabolism
blood supply of rectum**
upper, middle, and lower hemorrhoidal veins
what is the MAIN ingredient in a suppository
what is the purpose of it
the base
helps to formulate drug in suppository and allows for drug release and bioavailability
explain how a suppository base should behave at room temp vs at body temp
should remain solid at room temp and melt or dissolve at body temp
name 2 different classifications of suppository bases and give examples
oleaginous/fatty base - COCOA BUTTER
hydrophilic bases – glycerinated gelatin and PEG
we want drugs with ______ partition coefficients to be absorbed through the rectum
HIGH
the rectal membrane is lipophilic - want lipophilic drug
what can you say about the desired particle size of a drug in a suppository
want pretty small to be able to permeate the membrane and leave the base
smaller particles = higher surface area — BETTER DISSOLUTION AND RAPID ABSORPTION
