drug administration and absorption Flashcards
what are the four main processes of pharmakokinetics
absorption, distribution, metabolism, elimination/excretion
what are some routes of drug administration
topical, parenternal, enteral
what are some routes of topical administration
skin, inhalers, eye or ear drops
what are some routes of enteral
oral and rectal
what are parenteral routes of adminstration
IV, sub cut, IM, transdermal, intrathecal, sublingual
what is the one organ system we can access topically
the lungs through inhalers
what is the most complex process in adminstration
oral
drugs that are administered first hit what first
the liver first
why thorugh the oral route, is part of the drug lost
a part of the drug is lost and it is metabolized by the liver
what is the route of enteral adminsitration
mouth, liver, metabolism, systemic circulation
what is drug absorption scientifically
the movement of a drug from its site of administration across body membranes, and into circulating fluids
most rapid form of administration
IV
how does route of administration affect the drug absorption
some routes of administration are faster than others when it comes to absorption.
how do drug properties and formulation affect absorption
liquid absorbed faster than drugs in their liquid form
how does drug dosage affect absorption
wiht an increased loading lose, the drug concentration gradient will increase, causing more drug
how can we manipulate how a drug is being absorped
we can give alot of drug (loading dose) at first to increase the concentration gradient of the drug
blood flow how does it affect absorption
administering the drug at a site that has good blood ciruclation so it is able to get in faster
how can intestinal p-glycorprotiens affect drug administration
it will throw the drug to be eliminated
in order for a drug to enter circulation what must a drug pass through
lipid rich plasma membrane
in order for an orally administered drug to be dissolved, what properties must it have?
it must be both water soluble and fat soluble
why must an orally administered drug be both water and fat soluble
because in order to enter circulation, a drug must first pass through the stomach intestinal fluids that are mainly composed of water (water soluble) afterwards, the drug must be able to pass through lipid rich plasma membranes (fat soluble)
for highly fat soluble drugs, what might you advise your client to do?
to take the medication with a big meal, the fats in the meal compensate for the aqueous environment around it
if a drug is highly water soluble, how can you administer it?
through IV, it skips the process of absorption
if a drug is mainly polar, or fat soluble, why must it undergo absorption instead of being put through an IV
only water soluble can be put through an IV, fat soluble needs to be absorped
a drug can not be absorbed untill it is free from what?
its excipient
what is an excipient
these are particles that either add bulk to the tablet, enhance the rate of absorption, or slow the rate of dissolution
if a drug lets go of the excipient quickly, what does this mean
that it is rapid release, durg does not last for as long
what does a slow release excipient do? what kind of drugs would you want to have this?
allows for longer release of the medication, slowly dissolved, slowly absorped - you would want drugs that have a single dose a day
what is passive diffusion
drugs are diffused around the concentration gradient
what is carrier mediated transport
these are larger drugs that must be ascorted across biological membranes to their target site with the use of energy
ph of stomach
2
ph of small intestine
8
acids when you put in water what happens
give up a proton
weak bases
take on a proton in water becoming charged
weakly acidic drugs are absorbed where
stomach
when weakly acidic drugs go into the stomach what happens
they become charged
the fat soluble non-polar form a drug is absorbed where
in the stomach
weak acidic drugs are poorly absorbed where
in the intestines
what does the henderson-hasselbaclh do
as explains how like dissolves like
