drug targeting

1. DRUG TARGETING
Presented by
Grandhi Sandeep Ganesh
1

2. ABSTRACT
Targeted drug delivery also known as smart drug
delivery ,is a method of treatment that involves the
selective transport of drugs to targeted organs, tissues and
cells through a variety of drugs carrier . It is usually
designed to improve the pharmacological and therapeutic
properties of conventional drugs and to over come
problems such as limited solubility , drug aggregation ,
lack of selectivity and to reduce normal tissue damage.
The various drug targeting strategies are- Active targeting ,
passive targeting , inverse targeting , physical targeting ,
ligand mediated targeting , dual targeting and double
targeting , combinational targeting.
2

3. DEFINITION
It is defined as the ability of a drug to accumulate the
target organ or tissue selectively such that the concentration of
drug at diseased site is high (target organ)and the
concentration is low at non-target organ to prevent unwanted
side effects or toxic effects.
CARRIER
carriers are molecules or any other systems responsible
for the successful transportation of the drug to the site of
interest.
3

4. 4
CARRIER SYSTEMS USED ARE:
1.colloidal carriers
2.cellular carriers
3.supramolecular delivery systems
4.polymer based system
5.macromolecular carriers

5. Pharmaceutical reason:
• Drug instability
• Low solubility
Pharmacokinetic reasons :
• Poor absorption
• Short half –life
• Large volume of distribution
Pharmacodynamic reasons:
• Low specificity
• Low therapeutic index
5
REASON FOR DRUG TARGETING

6. LEVELS OF DRUG TARGETING
6

7. It involves the modification or functionalization of
drug carriers so that the contents are delivered to the site.
TYPES:
1.First order targeting
2.Second order targeting
3.Third order targeting
1.FIRST ORDER TARGETTING:(ORGAN
COMPARTMENTALIZATION)
Restricted distribution of the drug carrier system to the
capillary bed of a pre determined target site,organ or tissue.
Eg:compartmental targeting in lymphatics,peritoneal
cavity,joints,lungs,eyes etc. 7
ACTIVE TARGETING

8. 2.SECOND ORDER TARGETING:( CELLULAR
TARGETING)
The selective drug delivery to a specific cell type such
as tumour cells.
Eg : Selective drug delivery to kupffer cells in the liver.
3.THIRD ORDER KINETICS:(INTRACELLULAR
TARGETING)
Drug delivery specifically to the intracellular
organelles of the target cells.
Eg : Receptor based ligand mediated endocytosis
Lysosomal degradation of liver
8

9. PASSIVE TARGETING
System that target the systemic circulation are generally
characterised as passive drug delivery system.
Passive targeting involves transport of nano carriers
through leaky tumor capillary fenestrations into the tumor
interstitium and cells by passive diffusion.
Drug targeting occurs due to body’s natural response to the
physico chemical properties of drug or carriers.
 Bio distribution of carrier system through which it
eventually accumulate in organ compartment of body.
 Eg : uptake of some colloids by RES especially in
liver or spleen .
9

10. 10

11. INVERSE TARGETING
It is a result of the avoidance of passive uptake of colloidal
carriers by the RES.
It is based on attempts to circumvent and avoid passive
uptake of colloidal carriers by RES leading to reversion of
bio-distribution trend of the carrier.
Other strategies include modification and defined
manipulation of the size , surface charge , composition ,
surface rigidity and hydro-philicity characteristics of carriers
for desirable bio-fate.
It can be achieved by:
Suppressing the function of RES by pre injection of a
large amount of blank colloidal carriers or macromolecules
like dextran sulphate. 11

12. LIGAND MEDIATED TARGETING
 Ligands are carrier surface group and which can
selectively direct the carrier to the pre-specified site
housing the appropriate receptor units to serve as “homing
device” to the carrier/drug.
 most of the carrier are colloidal in nature and can be
specifically funtionalized using various biologically
relevant molecular ligands including
polypeptides,oligosaccharides , viral proteins and
fusogenic residues
 It can be achieved using specific mechanisms such as
receptor dependent uptake of natural LDL particles and
synthetic lipid micro emulsions of partially reconstituted
LDL particles coated with the apoproteins.
12

13. 13

14. PHYSICAL TARGETING
DEFINITION:
It is defined as selective drug delivery that is programmed
or monitored using at external level(ex-vivo) with the help
of physical means like pH , temperature , light intensity &
ionic strength.
 It is also known as triggered release.
 This approach was found exceptional for tumor
targeting as well as cytosolic delivery of entrapped drug or
genetic material
14

15. 15

16. 16
Drug targeting using carrier molecules, having intrinsic
antiviral effect thus synergies the antivira leffect of the
loaded active drug.
Based on this approach, drug conjugates can be prepared
with fortified activity profile against the viral replication.
In this targeting approach, carrier molecule, itself have their
own therapeutic activity and thus increase the therapeutic
effect of drug.
Advantages:
The virus replication process can be attacked at
multiple points, excluding the possibilities of resistant viral
strain development.
DUAL TARGETING

17. 17
In order to achieve a double targeting effect, site specificity of the drug, by
virtue of targeting moiety, a high specificity module(mainly a photosensitizer) is
linked to antibodies
Double Targeting
Targeting drugs to
specific organs, tissues,
cells or even sub cellular
compartment
Spatial
control
Tempo
ral
control
Double
targeting
Controlling the rate of
drug delivery to target
site

18. 18
Suggested by Petit and Gombtz.
Site-specific delivery of proteins and peptides.
These targeting systems are equipped with
carriers, polymers and homing devices of
molecular specificity that could provide a direct
approach to target site
COMBINATION TARGETING

19. REFERENCES
1. Lachman/Liberman’s The Theory and Practice of
Industrial pharmacy .
2. Targeted and controlled drug delivery (Novel
carrier systems),S P Vyas and R K Khar.
3. www.sciencedirect.com
19