Transport through biological membrane

1. CARRIER
MADIATED
TRANSPORT
Submitted by –
KULDIP DEKA
ROLL NO : 19
B.PHARM 4TH YEAR
DEPARTMENT OF PHARMACEUTICAL SCIENCES
DIBRUGARH UNIVERSITY

2. Carrier mediated transport:
Movement which occurs across membrane,
such as blood-brain barrier and GIT mucosa.
The passage of glucose, amino acids, and
other polar molecules through the cell
membrane is mediated by carrier proteins in the
cell membrane.
Carrier-mediated transport exhibits the
properties of specificity, competition, and
saturation. The transport rate of molecules such
as glucose reaches a maximum when the carriers
are saturated.

3. In case of drug-
If the drug is lipophilic drug may
pass through the cell or go around it.
If the drug has a low molecular
weight and is lipophilic, the lipid cell
membrane is not a barrier to drug
diffusion and absorption.
In the intestine, drugs and other
molecules can go through the intestinal
epithelial cells by either diffusion or a
carrier-mediated mechanism.

4. Types of carrier mediated
transport-
1.Active Transport
2.Passive diffusion
3.Facilitated diffusion
4.Vesicular Transport
5.Carrier mediated intestinal
transport
6.Ion pair formation

5. 1] ACTIVE TRANSPORT:
 Transport method that moves particles
from an area of low concentration to an area
of high concentration or against a
concentration gradient.
 It is an energy-consuming Process, energy
obtained from ATP in active transport can be
direct or indirect. Direct use of ATP is called
primary active transport, and indirect use is
called secondary active transport.

6. Primary active carrier mechanism
• Primary Active Transport of the
sodium/potassium (Na+ /K+) pump in nerve
cells

7. Secondary active transport:
Use an electrochemical gradient as a source of
energy to transport molecules or ions across a cell
membrane
• In this type of active transport, the energy to
pump 1 solute is derived from the downhill movement of
another solute.These are of 2 types:
• 1. Symport: when the concentration gradient are
such that both the solutes move in same direction.
• Eg-Na+/neurotransmitter co-transporters)
• 2. Antiport: when the concentration gradient are
such that both the solute move in opposite direction
• Eg-Na,Ca exchangers

8. 2] Passive
diffusionDrug molecules transport from High conc. to low conc.
 Passive transport is a movement of biochemicals and
other atomic or molecular substances across membranes.
Unlike active transport, it does not require an input
of chemical energy, being driven by the growth
of entropy of the system.
The rate of passive transport depends on the semi-
permeability of the cell membrane, which, in turn,
depends on the organization and characteristics of the
membrane lipids and proteins.
The four main kinds of passive transport
are diffusion, facilitated diffusion, filtration and osmosis.

10. Facilitated
diffusion is the process of spontaneous passive
transport of molecules or ions across a biological
membrane via specific transmembrane integral
proteins,differing from active transport in that the
drug moves along a concentration gradient
Therefore, this system does not require energy input.
3] Facilitated diffusion:
Example: entry
of glucose into
muscle and fat
cells by GLUT4

11. 4] Carrier mediated intestinal
transport
Various carrier-mediated systems
(transporters) are present at the intestinal
brush border and basolateral membrane for
the absorption of specific ions and nutrients
essential for the body. Many drugs are
absorbed by these carriers because of the
structural similarity to natural substrates. A
transmembrane protein, P-glycoprotein (Pgp),
has been identified in the intestine.

12. Intestine Transporters and
Examples of Drugs Transported

13. 5] Vesicular
transport:
Vesicular transport is the process of
engulfing particles or dissolved materials by
the cell. Pinocytosis refers to the engulfment
of small solutes or fluid, whereas phagocytosis
refers to the engulfment of larger particles or
macromolecules, generally by macrophages.
Endocytosis and exocytosis are the processes
of moving specific macromolecules into and
out of a cell, respectively.

14. 6] Ion-pair
formation :
 Highly ionized or charged molecules,
such as quaternary nitrogen compounds and
sulphonic acid transport in this process.
These drugs penetrate by linked up with an
oppositely charged endogenous ions like
mucin, an ion pair is formed in which the
overall charge is neutral. This neutral
complex diffuses more easily across the
membrane.
For example, In case of propranolol, a basic drug
that forms an ion pair with oleic acid.

15. THANK YOU

16. REFERENCES:
•http://www.pharmacorama.com/en/Sections/NAK-
ATPase-Digoxin.php
•Applied biopharmaceutics and pharmacokinetics,5th
edition by Leon Shargel,, Susanna Wu Pong, Andrew
B.C. YU,PUBLISHER:MC GRAW HILL’S
•Essentials of medical pharmacology ,6th edition k.d
tripathi.page no.13-15
•https://www.boundless.com/biology/textbooks/boun
dless-biology-textbook/structure-and-function-of-
plasma-membranes-5/active-transport-66/primary-
active-transport-337-11474/
•http://www.mhhe.com/biosci/ap/foxhumphys/studen
t/olc/chap06summary.html