This document discusses the mechanisms of drug absorption. It outlines the main processes including passive diffusion, pore transport, ion pair transport, and carrier-mediated transport systems like facilitated diffusion and active transport. Active transport includes primary active transport, which requires ATP directly, and secondary active transport, which utilizes the energy from transporting one ion to transport another. Endocytosis is also discussed as a minor mechanism of absorption involving engulfing materials within the cell membrane. In conclusion, drug absorption is a key part of the ADME process and proper pharmacokinetics is important for effective drug activity.

1. Topic :-Mechanism Of Drug Absorption
Presented By
Tuhin Samanta
B.Pharm

2. INTRODUCTION
Pharmacokinetics and pharmacodynamics helps to
maintain the products effective measurement of any
kind of formulation by invitro and invivo test.
ADME is the main function process after
administration of a doses from and this process can
be were defined by pharmacodynamics and
pharmacokinetics.

3. Pharmacokinetics
 Pharmacokinetics means what the body dose to the drug.
 it is mainly concerned with absorption, Distribution, metabolism and
excretion of the drug.
A. Absorption :- Absorption can be defined as the process of
movement of unchanged drug from the site of administration into
systemic circulation.
Mechanism Of Drug Absorption :-
1) Parive diffusion :-
 Also called non-ionic diffusion.
 90% of drugs absorbed by passive diffusion process.
 No carrier is required.
 No energy is required.

4. 2) Pore transport :-
 Also called connective transport, bulk flow, filtration .
 Here passage of the drugs occur through the aqueous pores present in
the membrane.
 The driving force is the osmotic pressure difference across the
membrane.
 This process important for Absorption of low molecular weight and
low molecular size and water soluble drugs. E.g.- water, glucose etc.
3) Ion pair transport :-
 Drugs like quaternary ammonium compounds, sulphonic drugs,
which are ionized at all pH vales are absorbed ley ion pair transport.
 Due to ionization, these drugs having very low lipophilicits-test they
penetrate the membrane by forming revisable neutral complexes
with endogenous ions of the GIT like mucin such Neutral complexes
have required lipophilicity for passive diffusion.

5. 4) Carrier Mediated Transport System
A. Facilitated Diffusion B. Active transport
A. Facilitated Diffusion:-
 Carrier mediated transport system.
 Passage of the drug molecule occurs from higher
concentration to lower concentration.
 Driving force is the concentration gradient error the
membrane.
 No energy is required.

6. B) Active Transport
This transport mechanism requires energy in the form of ATP. Active
transport process subdivided into:-
a) Primary active transport:-
 ATP required directly.
 This process transfer only one ion or molecule in one direction. So it
is uuiporter . E.g. Absorption of glucose.
 Carrier proteins involved in primary active transport are mainly two
types: I ) Ion transporter
II ) ABC transporter
I ) Ion transporters:- Responsible for transporting ions in or out of
the cell. Two types of ion transporter are present which responsible
for intestinal. Absorption of drugs:- Organic anion transporter :-
helps in absorption pravastatin , Atorvastatin.
Organic cat ion transporter:- helps in Absorption of
diphenydramine.

7. II) ABC transport:-
Responsible for transporting small foreign molecules specially out of
cells. So these pumps are called efflux pump.
 Example of ABC transporter is P- glycoprotein .It responsible for
pumping hydrophobic drugs out of the cells.
 Presence of these types of transporter molecule in cells makes the cell
resistant to variety of anti cancer drugs. That’s why P- glycoprotein
called multi-drug resistant (MDR) protein.
b) Secondary Active Transport :-
 No direct requirement of ATP
 The energy required in the transporting an ion aids transport of
another ion or molecule either in the same direction or in the opposite
direction.

8. Endocytosis
Minor transport mechanism which involves engulfing extracellular
materials with in a segment of the cell membrane to form a vesicle
which is then pricked off intracellular .
 This phenomenon is responsible for absorption of fat starch, oil
soluble vitamin like A,D,E,K and water soluble vitamin like Vit B12,
Drugs like insulin.
 Endocytosis
Phagocytosis Pirocytosis
Adsorptive uptake uptake of fluid solute.
Of solid materials.
 Orally administered Sabine polio vaccine, botulihicim toxin are
observed by

9. Conclusion
The drug absorbent is the main function of
ADME if the absorption process are as per the
standard pharmacokinetics norms then activity
by the product will be better.

10. Reference
Abdou, H.M.: Dissolution, Bioavailability and
Bioequivalence, Pennsylvania, Mack Publishing
Company, 1989.
Bankar, U.V.: Pharmaceutical Dissolution Testing,
New York, Marcel Dekker, Inc., 1992.
Florence, A.T and Attwood, D.: Physicochemical
Principles Of Pharmacy, London, Macmillan, 1981.