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1. Absorption of Drugs
• 213005 Rushab Jain
• 213006 Pratiik Lokhande
• 213013 Vaishali Kale
• 213008 Shweta Khandare

2. INTRODUCTION
A drug is injected intravascularly (iv or ia)
directly enters into systemic circulation.
Majority of drugs are administered
extravascularly (generally orally).
Such drugs can exert the pharmacological
action only when they come into systemic
circulation from their site of administration

3. Definition of
absorption
The process of movement of unchanged drug
from the site of administration to systemic
circulation.
The effectiveness of a drug can only be
assessed by its concentration at the site of
action.
It is difficult to measure the drug
concentration at such site.Instead, the
concentration can be measured more correctly
in plasma.

4. CELL
MEMBRANE
• Cell membranpermeable es living
cell from nonliving surroundings Thin
barrier = 8nm thick
• Controls traffic in & out of the cell
selectively permeable
• Allows some substances to cross
more easily than others hydrophobic
vs hydrophilic.
• Made of phospholipids, proteins &
other macromolecules

5. Topic :-Mechanism Of DrugAbsorption

6. 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.

7. 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.

8. 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.

9. 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.

10. B) Active Transport
This transport mechanism requires energy in the form ofATP.Active
transport process subdivided into:-
a) Primary active transport:-
 A
TP 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 inAbsorption of
diphenydramine.

11. II) ABC transport:-
Responsible for transporting small foreign molecules specially out of
cells. So these pumps are called efflux pump.
 Example ofABC 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 ofATP
 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.

12. 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 likeA,D,E,K and water soluble vitamin like Vit B12,
Drugs like insulin.
 Endocytosis
Pirocytosis
uptake of fluid solute.
Phagocytosis
Adsorptive uptake
Of solid materials.
 Orally administered Sabine polio vaccine, botulihicim toxin are
observed by

13. 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.

14. FACTORS AFFECTING
DRUG ABSORPTION

15. pH
• The cell membrane characteristics demand
that drug be in unionised form for good
absorption
• Acidic drugs are best absorbed in acidic
medium. Ex- Salicylates(like aspirin),
Barbiturates
• Basic drugs are best absorbed in basic
medium. Ex- Amphetamines, Morphine,
Quinine

16. Blood Flow

17. Surface Area
and Contact
Time

18. Multidrug
resistance

19. Solubility

20. Instability of
drug

21. First Pass
Effect

22. BIOAVAILABILITY
• The rate and extent to which the active
ingredient or active moiety is absorbed from
a drug product and becomes available at site
of action
• It is defined as rate and extent of absorption
of unchanged drug from its dosage form and
become available at site of action.

23. Concept of
Bioavailability
• Rate and extent at which therapeutically
active drug reaches system circulation.
• The fraction of administered dose that
reaches systemic circulation in contrast to
that stated on labels
• Rate and extent of absorption of unchanged
drug from its dosage form
• A measure relative to some standard of rate
and amount of drug, which reaches systemic
circulation unchanged following
administration of dosage form

24. Types of
Bioavailability
• Absolute Bioavailability
Bioavailability of orally administered drug is
compared with bioavailability obtained of same
drug when it is administered intravenously
• Relative Bioavailability
Bioavailability of a formulation of a certain drug
(A) is compared with another formulation (B) of
the same drug. It is used to assess the
bioequivalence of two drug products.

25. • Range of Bioavailability- 0 to 1
• Usually expressed in percentage. Absolute
Bioavailability of 1 (100%) indicates
complete absorption.
• Relative bioavailability of 1 (or 100%) implies
that bioavailability of drug from both the
dosage forms is same but does not include
completeness of systemic drug absorption.