HTHSCI 2H03 Study Guide - Fall 2018, Comprehensive Midterm Notes - Prescription Drug, Pharmacotherapy, Pharmacology
12 Oct 2018
School
Department
Course
Professor
HTHSCI 2H03
MIDTERM EXAM
STUDY GUIDE
Fall 2018
DRUG ADMINISTRATION &
ABSORPTION
DWE D
.
§D
.
a
.
I
⇒§DD
Pharmacokinetics
• 4main processes :Administration
Distribution
Metabolism
Elimination IExcretion
Routes of Drug Administration
y
hot Involving Gl ..
°
Top
.
cat
°
parenteral bloodstreamtransports drug to desired organ the tallest
-
Skin
-
Intravenous →fastest route t most complete
-
Inhalers
-
Subcutaneous
-
-
Eye tear drops Intramuscular Fastest Route
°
Enteral
→ Involving Gl -
transdermal
-
Inhaled
-
Rectal
-
Oral
--
.
--
Oral Intra the cat → spine sublingual Subcutaneous Transdermal
-
-
Rectal Sublingual
Routes of Administration
y
Drug administration first hits portal circulation thaving gone through the
G1 system tthen having to go into liver ,
it diminishes the drugs full amount
Drug Administration
°
Drug Administration :the movement of a drug from its site of administration across body membranes
,
and into
circulating fluids Ibloodstream )
Factors Affecting Drug Absorption
°
Route of Administration
°
Drug properties and formulation
→
liquids are absorbed faster than solids
•
Drug dosage →Drugs more from Tto t;take loading dose then lower to maintenance dote :.gradient allows Tabsorption
•
Blood How at administration site → site has to be well vascularized
°
Digestive motility
→Diarrhea =Ttransit time i.Iv drug exposure tXdrug absorption
°
Digestive tract enzymes
→
Enzymes digest meds before they reach desired Site
• Intestinal P-Glycoproteins IP -Gp )→It affinity ,transporters grab dmg tput it hack In intestine to be eliminated
Absorption -Acomplicated Process
°
Oral drugs are most commonly available in tablet or capsule form
°
Drugs must dissolve first Iseparate from excipient )in stomach and/or intestinal fluids which are mostly water
•
To enter the circulation lie . absorption ),drugs must pass through lipid rich plasma membranes ¥arehbe
both water tfat soluble
Dissolving Drum 1h Biological Fluids
°
orally administered drugs must first be dissolved before they can be absorbed into the bloodstream
°
Biological fluids dissolve drugs that share the same physicochemical characteristics .
'
.like dissolves like
•
Biological fluids consist mostly of water
,
apopular environment →Oral meds need to be sufficiently water soluble
to be absorbed
•
This process takes time especially it the drug is highly non polar ,tonset of action →take fat soluble drug w/ food as
fat from food will help dissolve
•
It a drug is highly water soluble lie .polar )then the drug can be easily administered the excipient
IV
,
as it 'll did solve In the blood
IIV drug administration "
skips
"
the process of absorption
Afast onset of action can be expected
•
If a drug is poorly water soluble lie . mainly nonpolar ,or fat soluble )then the drug cant be administered N
-
All other routes require absorption
-
oral administration is the most common form of drug administration
-
ASlower onset of acton should be expected
•
Most drugs are bound to excipient Iparticles )that either :
-
Add bulk to the tablet
-
Trate of distribution
-
y
ex apent are large and cant cross
trate of dissolution membranes
•
Adrug cant be absorbed until Its tree of exc ,plants , it must be dissolved -slow release drugs slowly let go Ot
excipient to tr dotes to get same
coverage while rapid release drugs let
Absorption go of excipient quickly
•
Drugs can be absorbed via two distinct processes
Ipassive Diffusion
-
Drugs must be small in molecular size and nonpolar Inon whiled ,lipid soluble )to pass through biological
membranes Via diffusion
-
Movement dictated by the concentration gradient
2Carrier mediated transport
-
Drugs that are large in molecular size or polar (water soluble )must be actively transported across
biological membranes 1h order to reach target Site
-
This process often requires energy
Dissolving ,Absorbing t Distributing Drugs Across Membranes tTissues
°
Drug =D
and Excipient
= Orange block
°
No drugs are tree .
'
. encouraging
drugs to free themselves
• once in blood Stream , it bound to albumin or PGP they wont cross
•
With I concentration of thee drug ,albumin will release drugs ,
and P.Gp 's purpose Is to grab tree drugs
t send them to intestines
Document Summary
Gl bloodstreamtransports drug to desired organ the tallest. G1 administration first hits system t then having to portal into go circulation t having gone through the liver it diminishes the drugs full amount y. Administration the movement of a drug from its site of administration across body membranes and into circulating fluids. Drug properties and formulation liquids are absorbed faster than solids. T to t take loading dose then lower to maintenance dote gradient allows. How at administration site site has to be well vascularized. It affinity transporters grab dmg t put it hack. Oral drugs are most commonly available in tablet or capsule form. I separate from excipient in stomach and/or intestinal fluids which are mostly water. To enter the circulation lie . absorption drugs must pass through lipid rich plasma membranes. Fluids orally administered drugs must first be dissolved before they can be absorbed into the bloodstream.
