3. The process of movement of
unchanged drug from the site of
administration to systemic
circulation.
3
4. The majority of drug are administered
extravascularly generally orally
The drug can exerts their pharmacological
action when they come in to blood
circulation from their site of application,
and for this absorption is an important step
Drug absorption is defined as the process
of movement of unchanged drug from the
site of administration to systemic circulation
4
5. 1. Passive diffusion
2. Pore transport
3. Carrier mediated transport
4. Facilitated diffusion
5. Active transport
6. Electrochemical diffusion
7. Ion-pair transport
8. endocytosis 5
6. Direction of diffusion always from higher to lower
concentration.
down the equilibrium exchange of
gradient solute 6
7. Driving force is concentration gradient.
Down hill transport occur.
Drug transfer directly proportional
to concentration gradient across
membrane.
Greater membrane/water partition
coefficient faster the absorption.
7
8. Which states that the drug molecules
diffuse from a region of higher conc. to
lower conc. until equilibrium is attained.
Sink condition.
8
9. Absorption of low molecular weight
drug .
Driving force is hydrostatic pressure.
Solvent drag.
Permeation through water filled
channel.
9
13. Operate down the concentration
gradient.
Faster than passive diffusion.
No energy expenditure involved.
Glucose transport occur.
13
14. Uses transport proteins
Facilitated Diffusion to Equilibrium
Figure 5- 21: Diffusion stops at equilibrium (panoramic lower left 66%)
14
15. cell uses energy
actively moves molecules to where
they are needed
Movement from an area of low
concentration to an area of high
concentration
(Low High)
15
16. Carrier proteins used in active transport
include:
-uniporters – move one molecule at a
time
-symporters – move two molecules
in the same direction
-antiporters – move two molecules
in opposite directions
16
17. Charge on the membrane influence
the permeation of drug.
Unionized molecule>anions>cations
When cations atached to negatively
charged intracelular membrane then
create electrical gradient.
17
18. Drug penetrate the membrane by
forming reversible neutral complex
with endogenous ions of GIT like
mucin.
Example; sulfonic acid
18
19. Transport large particles or fluid
droplets through membrane in vesicles
uses ATP
Exocytosis –transport out of cell
Endocytosis –transport into cell
phagocytosis – engulfing large
particles
pinocytosis – taking in fluid
droplets
19
21. Milo Glibaldi Biopharmaceutics and
Clinical
Pharmaceutics, Reprint 2006 , 4thEdn
published by Pharma book syndicate
Hydrabad, page number 24-32
Robert E.Notari Biopharmaceutics and
clinical Pharmaceutics, Second Indian
reprint 2008, CBS Publisher and
distributors New Delhi, Page no. 22-44
Leon Shargel /Andrew B.C. YU.
Biopharmaceutics and Pharmaceutics,
4th Edn 1999, Published by McGraw-Hill
companies New York, page no. 99-108
21