Occular Drug Delivery System ODDS advantages of OODS disadvantages of ODDS Factors effecting ODDS Barriers of drug permeation methods to overcome barriers drug delivery system novel drug delivery system B. pharmacy M. pharmacy

1. Presented by:
Puttamreddy.Kavyasri
M.Pharmacy(Pharmaceutics)2023-2024
MBschool of pharmaceutical sciences(MBU).
Occular Drug Delivery systems

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Contents
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Ideal characteristics of ODDS
Occular drug delivery system
Definition
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Barriers:
1.Barriers of drug permeation.
2.Methods to overcome barriers.
Advantages and Disadvantages

3. Definition:
ODDS is a dosage form ,vehicle ,or
system intended for instilling
,administering ,delivering
drug/medicine to eye against any
aliment or disorder involving or
affecting vision.
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1.It is mainly associated with need to treat opthalmic disease.
2.These are ment for local therapy and not for systemic action.
3.It is also be defined as the administration between eye lids
and eye ball.
4.Opthalmic preparations are sterile product implant
O c c u l a r D r u g D e l i v a r y s y s t e m s

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S T Y L E / Presentation Template
1.Good corneal penetration.
2.Simplicity of intiallation for patient.
3.Patient compliance.
4.Lower toxicity and side effects.
5.Minimized percorneal drug loss.
6.Should not cause blurred vision.
7.Non-greassy in nature.
I d e a l c h a r a c t e r i s t i c s o f O D D S :
 Epithelium - Only non ionized drug penetrate
 Stroma - Only ionized drug pass
so drug must have capacity to exit in both ionized and
nonionized form for a better penetration.

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S T Y L E / Presentation Template
Advantage: Disadvantage:
Quick absorption.
Eaisly administred by patient.
It can also be given to
unconcious patient if need.
It improve patient compliance
and comfort.
Increased shelf life.
Low bioavailability.
Drug loss occur due to
lacrimal secretion or tears.
Drug solution stay in eye for
small time.
The instability of the
dissolved drug.
FACTORS AFFECTING INTRAOCULAR BIOAVAILABILITY:
• Inflow and out flow of lacrimal fluids.
• Efficient naso-lacrimal drainage.
• Interaction of drug with lacrimal fluid.
• Dilution with tears.
• Corneal barriers.
• Active ion transport at cornea.

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S T Y L E / Presentation Template Corneal absorption:
Outer epithelium: rate limiting barrier, with
pore size 60a ,only access to small ionic and
lipophilic molecules.
Trans cellular taransport:transport between
corneal epithelium and stroma.
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ABSORPTION:

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S T Y L E / Presentation Template
ABSORPTION:
Penetration across sclera and
conjucteva into intra ocular tissues.
Non productive:because penetrated
drug is absorption by general
circulation.
Conjectiva is more permeable than
cornea especially hydrophilic
molecules due to much lower
expression of tight junction proteins
relative to corneal epithelium.

9. 4.Corneal and non corneal routes of absorption:
 Opthalmic medicines are washed away via lacrimal drainage and systemic
absorption through the conjunctiva.
 This allow the absorption of only small concentration of the drug.
 Small lipophilic molecules of topical drugs absorb through the cornea,while large
hydrophilic molecules to topical drugs through -
 Non corneal absorption :
Penetration of drugs accrose sclera and conjuctive into intraoccular tissue.
 Corneal absorption :
Between corneal epithilium and stroma.
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S T Y L E / Presentation Template
1. Drug loss from the
occular surface
4. corneal and non
corneal routes
of abstruction
2. Lacrimal fluid - eye barrier
3. Blood - occular barrier 5. Diluted with tears.
I n t r a
o c c u l a r
B a r r i e r s :
occular drug delivery system

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12. 1. Drug loss from occular surface:
 The corneal epithelium barrier to hydrophilic drug transport through
intercellular spaces.
 Therefore,Lipohilic drugs in compare to hydrophilic drugs are having
higher permeability in corneae.
• The cornea is a very tight multi-layered tissue that is mainly
composed of five sections:
 Epithelium
 Bowman’s membrane
 Stroma
 Descemet’s membrane
 Endothelium.
Out of these it’s the EPITHELIUM which acts as the principal barrier:
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13. another surface layer barrieris stroma
 It is with multiple layers of hexagonally arranged
collagen fibers containing aqueous pores or channels
allow hydrophilic drugs to eaisly pass through but it act
as a significant barrier for lipophilic drugs.
 Thus for a drug to have optimum bioavailability ,it should
have the right balance between lipophilicity and
hydrophilicity. The remaining layers are leaky and do not
act as significant barriers.
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14. 2.Lacrimal fluid eye barriers:
 The lacrimal fluid is an isotonic aqueous solution containing
a mixture of proteins (such as lysozyme) as well as lipids.
 Rapid clearance from the precorneal area by lacrimation
and through nasolacrimal drainage and spillage futher
reduces contact time between the tissue and drug
molecules.
 After administration/installation,the lacrimal fluid
remove the instilled compound from eye.
 The lacrimal turnover rate is only 1 μ l/min,excess
volume of the instilled fluid flows to the nasolacrimal
duct with in few min.
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15. 3. Blood ocular barriers:
• These barriers provide protection to the eye from xenobiotics ,into
blood strem.
• These barriers are 2 types: 1.Blood aquous barriers.
2.Blood retina barriers.
Blood aqueous barrier : It is formed by non pigmented ciliary epithelial cells of ciliary body
and endothilial cells of blood vessels in iris.
Blood retinal barrier : Non fenestrated capillaries of the retinal circulation and tight -
junctions between retinal epithelial from chorio-capillaris into the retina. 15

16. 5. Diluted with tears:
Drugs get diluted with tear and non permeable into the eye.
The average tear volume is 7-9μL with a turnover
rate of 16% per minute
Thus drugs administered as eye drops need to be
isotonic and non irritating to prevent significant
precorneal loss.
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17. Methods to over come
 The main objective of occular drug delivary system is to
increase bioavailability and control release of drug.
 Surface Active Agent:
Agents that reduce surfacetenson,increase corneal wetting
and therefore present more drug for absorption.
Eg : Benzalkonium Chloride used as preservative also act as
wetting agent.
 Prodrug form:
Prodrug is more lipophilic so more absorbed by epithelium
and afterthat converted into another form.
Eg: Dipivefrine(alpha adrenergic agonist antiglaucoma drug) is
lipophilic prodrug which hydrolysed by esterases into
adrenaline.
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18. SELECTED TYPES OF OCDDS::
1.Aquoes eye drops
2.oily eye drops
3.eye ointments
4.eye lotions
5.paper strips
6.ocuserts
7.hydro gel contact lenses
8.collagen shields
9.ophthalmic rods
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19. Mixture of semisolid and
solid hydrocarbons which
are non irritant and have
mealtingpoint and
softening point close to
body temp.
Eye droups undergone
changes by adding viscocity
enhancers - hydrophilic
polymers :
Cellulose ,bioadhesive agents
,polyvinylchloride
Viscous eye drops
Eye ointment
Enhance corneal drug
penetration by changing
liphophilicity and
hydrophilicity
derivatization of drug is
known as prodrugs
It is not only used by good
penetration but also for
sustain release.
Problem assosiate with
administration.
Gel
Prodrugs
Microionized particles
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20.  Liposomes
 Niosomes
 Naoparticles
 Nano suspension
Increase penetration:
Penetration enhancers
Microemulsion:
 EDTA
 Surfactant
 Bile salts
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21. REFERENCES.....
1. Y W. Chien, Novel Drug Delivery Systems, 2nd edition, revised and
expanded, Marcel Dekker, Inc., New York, 1992.
2. Robinson, J. R., Lee V. H. L, Controlled Drug Delivery Systems, Marcel
Dekker,Inc., New York, 1992.
3. Encyclopedia of controlled delivery, Editor- Edith Mathiowitz, Published by
WileyInterscience Publication, John Wiley and Sons, Inc, New York!
Chichester/Weinheim
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