Ocular drug delivery systems aim to overcome barriers to drug absorption by the eye and provide sustained drug release. They include novel formulations like liposomes, niosomes, microparticles and nanoparticles that can target ocular tissues. Controlled release systems like implants, contact lenses and Ocuserts maintain drug levels for extended periods. Alternative routes like intravitreal injections provide direct access to intraocular structures. Together, these approaches enhance ocular bioavailability and drug efficacy while reducing administration frequency.

1. OCULAR DRUG
DELIVERY SYSTEM
Presented By:- Rohit Grover
M Pharmacy 1st Sem
Guru Gobind Singh College Of Pharmacy
Yamuna Nagar , Haryana

2. OCULAR DRUG
DELIEVERY SYSTEM

3. INTRODUCTION
They are specialized dosage forms designed to be instilled onto the
external surface of the eye (topical), administered inside ( intraocular)
or adjacent (periocular) to the eye or used in conjunction with an
ophthalmic device
 The Novel approach of drug delivery system in which drug can
instilled on the cull de sac cavity of eye is known as Ocular Drug
Delivery System
 Cull de sac cavity : the space b/w eye lids and eye balls

4. Difference b/w Ophthalmic and Ocular
Drug Delivery System

5. COMPOSITION OF EYE
 Water – 98%
 Solid – 1.8$
 Organic Element :- Protein (0.67%) Sugar
(0.65%) Nacl (0.66%)
 Other Mineral Element :- Sodium ,
Potassium , Ammonia -0.79%

6. ANATOMY OF EYE
 Diameter 23mm
 Structure comprises of three
layers
1.Outer layer :
cornea( clear, transparent)
sclera(white, opaque)
2.Middle layer:
iris (anterior)
choroid (posterior)
ciliary body (intermediate)
3.Inner layer: Retina

7. SCLERA:
The protective outer layer(White of eye) of
the eye
White colored fibrous membrane
surrounding the eyeball
 it maintain the shape of the eye.
CORNEA:
The front of the sclera, is transparent,
Circular, Bulgy epithelial membrane
and allow light to enter the eye. the
cornea providing much of the eye’s
focusing power.
Cornea composed of 5 layers
Epithelium
Bowman’s Membrane
Stroma
Descemet’s Membrane
Endothelium
5 layers of cornea

8. The cornea has five main layers of cells:
1. Epithelium: The outer layer of the cells that acts as a barrier against damage and infection
2. Bowman's membrane: A thin, tough membrane
3. Stroma: Consist of collagen fibers and account for 90% of the cornea's thickness
4. Descemet's membrane: A thin membrane of collagen and elastic fiber
5. Endothelium: A layer very delicate cells that cannot regenerate and are Responsible for maintaining
partial corneal dehydration and transparency

9. FLUID SYSTEM:
AQUEOUS HUMOR
1. Secreted from blood through
epithelium of the ciliary body.
2. Secreted in posterior chamber
and transported to anterior
chamber.
VITREOUS HUMOR
1. Secreted from blood through
epithelium of the ciliary body.
2. Diffuse through the vitreous
body.

10. LACRIMAL GLANDS:
Secrete tears and wash foreign bodies.
CHOROID: It is the second layer of the eye and lies
between the sclera and retina it contains the blood vessels
that provide nourishment to the outer layer of the retina.
RETINA: It is the inner most layer in the eye. It converts
image into electrical impulses that are sent along the optic
nerve to the brain where the images are interpreted.
MACULA: It is located in the back of the eye in the
center of the retina. This area produces sharpest vision.

11. General Pathway For Ocular Drug Absorption

12. FACTORS AFFECTING OCULAR
ABSORPTION OF DRUGS
Nasolacrimal Drainage

13. Lacrimal Fluid
•When the eye drops are instilled in the cul-de-sac (space b/w eyelids and eye
balls), the drug solution gets diluted with the lacrimal fluid.
•This coupled with continuous tear flow decreases the volume and
concentration of drug reaching the target sites.
Nasolacrimal Drainage
•This drainage system is also responsible for reducing the contact time of the drug
solution with the corneal surface
Molecular size
•Small size particles like mannitol (mol.wt 182) can easily pass through an intact
cornea when compared to large sized particles like insulin and dextran

14. Partition Coefficient
Corneal membrane being lipophilic is highly permeable to lipophilic drugs
while hydrophilic drugs experience greater resistance from the epithelium for
penetration.
Charge
Surface of the corneal epithelium is negatively charged and hence it
favours the absorption of positively charged drug molecules.
Protein Binding
Upon instillation of the drug solution, proteins in the lacrimal fluid
bind with the drug molecules.
Only free or unbound drug molecules are able to undergo corneal
permeation. CONT…
.

15. Upon instillation of the drug solution, proteins in the lacrimal
fluid bind with the drug molecules.
Only free or unbound drug molecules are able to undergo
corneal permeation.

16. INTRAOCULAR BARRIERS
1
2
3
4
5

17. 1) Drug loss From Ocular Surface
 When we Insert the drug into the eye Lacrimal fluid ( tears) remove the drug
compounds from the eye surface Lacrimal Fluid turnover / secretion should be
1ul/min. But if there is increase in the fluid it reaches to the Nasolacrimal Duct within
a few minutes
 Due to this 80% of the instilled dose is lost thereby contact time of drug in the
precorneal surface is lost
2) Lacrimal Fluid Barrier
 Epithelium Layer of the cornea restrict the absorption of the drug from the lacrimal
Fluid into the eye
 The corneal epithelium cells forms the tight junctions to limit the paracellur drug
penetration. So Drug penetration get reduced
 Therefore lipophilic drugs in compare to hydrophilic drugs are having higher
permeability In the cornea.

18. 3) Blood Ocular Barrier
Basically these barriers provide protection to the eye ftom xenobiotics ( foreign substance
like dust)
These Barrier are of 2 types
1) Blood Ocular Barrier
2) Blood Retina Barrier
4) Corneal & Non Corneal Routes Of Absorption
 Lacrimal Drainage ( eye secretion ) & Systemic absorption washout the drug from the
conjunctiva.
 This allow the absorption of only small amount of drug
 Small lipophilic molecules of topical drugs absorb through the cornea while large
hydrophilic molecules of topical drugs through:-

19. 1. Non corneal Absorption :- Penetration of drug across clrea and conjunctiva into
intraocular tissue
2. Corneal Absorption:- B/w corneal epithelium and stroma
5)Dilution with Tears
Drug gets diluted with tears and not permeate inside the eye

20. Methods To Overcome Intraocular Barriers
ALTERNATIVE DRUG DELIVERY ROUTES
NOVEL DRUG DELIVERY SYSTEM

21. ALTERNATIVE DRUG DELIVERY ROUTES
INTRAVITREAL INJECTIONS
SUB CONJUNCTIVAL INJECTIONS
RETROBULBAR ROUTE
PERIBULBAR ROUTE
INTRACAMERAL ROUTE

23. INTRA VITERAL INJECTION
 It involves the delivering of the drug formulation directly into the vitreous humour
 It provides direct access to the vitreous and avoid both cornea and blood vessels
 Formulations such as suspensions , solutions can be administered through this route
SUB CONJUCTIVAL INJECTIONS
 This injection drivers the drug beneath the conjunctival membrane that lines the inner
surface of the eyelid
 It avoids both cornea and conjunctiva allowing the drug direct access to the sclera

24.  It has lesser side effects as compared to intravitreal injections
 Hydrophilic drugs , depot forming formulations can be delivered through this route
RETROBULBAR ROUTE
 Retrobulbar injection is given through eyelid and orbital fascia and it places the drug
into the retrobulbar space
 But it may damage the optic nerve
PERBULBAR ROUTE
 It involves drug in the orbit around the equator of the eye ball (globe).

25.  It is also a viable route of delivery of anaesthesia in the cataract surgery
 It is safer as compared to retrobulbar route
 Rice in intraocular pressure (IOP) is its drawback
INTRACAMERAL INJECTIONS
 This injections delivers drug into the anterior chamber
 It is more efficient and more cost effective methos of delivery of antibiotics

26. NOVEL DRUG DELIEVERY SYSTEM
Novel ocular drug delivery systems have been developed with an aim to provide the
following advantages.
1. Accurate and constant rate of drug delivery.
2. Provide sustained and controlled delivery of drugs.
3. Increase the intraocular bioavailability by prolonging the residence time of the drug in
the precorneal space.
4. Specifically targets the desired ocular tissues, thus preventing systemic drug delivery.
5. Overcomes the barriers to efficient delivery like lacrimation, nasolacrimal drainage,
conjunctival uptake etc.
6. Improve patient compliance and therapeutic efficacy of drugs.

27. Ocular Drug
Delivery
System
Vesicular
Systems
Liposomes
Niosomes &
Discomes
Controlled
Release
Systems
Implants
Contact lenses
Lacrisert
Microneedles
Iontophoresis
Particulate Nanoparticles
Microparticles
Ocuserts

28. VESICULAR SYSTEMS:-
1) LIPOSOMES:-
 These are biodegradable , non toxic and amphiphilic delivery system usually
formulated with phospholipids and cholesterol
 They can be utilized for both improving the permeability as well as well as
sustaining the release of the entrapped drugs
 Liposomes sustain the release of therapeutic agents into the vitreous and retina
choroid and avoids non targeted tissues (sclera & lens)
Liposomes are small artificial vesicles of spherical shape that can be
created from cholesterol and natural non-toxic phospholipids. Due to
their size and hydrophobic and hydrophilic character liposomes are
promising systems for drug delivery.

29. MERITS
Delivers drug at constant rate
Protect form metabolising enzyme
Biodegradable and non toxic
DEMERITS
Have shorter shelf life
Limited loading capacity
Difficulty in sterilization of liposomal formulation

30. HYDROPHILIC
HEAD
HYDROPHOBIC
TAIL
AQUEOUS
INTERIOR

31. 2)NIOSOMES AND DISCOMES
 These are bilayer structures which can entrap both
hydrophilic and lipophilic drugs
 The non- ionic surfactant bilayer exhibit low toxicity
and are chemically stable
Niosomes are similar to liposomes but are made up of nonionic
surfactants instead of phospholipids. They are tiny vesicles that can
encapsulate drugs or other substances. Niosomes are used in drug
delivery systems to enhance the stability and effectiveness of the
enclosed substances. can encapsulate drugs or other substances. and
effectiveness of the enclosed substances.

32.  Niosomes are also used in there modified form i.e
Discosomes in ophthalmology
 It contains non ionic surfactant
 These vesicles fir better in the cul- desac of the eye
and are not drained into systemic circulation because
of there large size and have high entrapment efficiency

33. CONTROLLED RELEASE SYSTEMS
1) IMPLANTS
 Implants are devices that control drug release by utilizing various degradable or non-
biodegradable polymeric membranes.
 Polyvinyl alcohol (PVA), ethylene vinyl acetate (EVA) are most commonly used on
biodegradable implant polymers.
 Advantages: Low burst effects
 Disadvantage: The implants need to be surgically removed
2) CONTACT LENSES (coated with drugs)
 Contact lenses can absorb water soluble drugs when soaked in drug solutions.
 They are placed in the eye for releasing the drug for a long period of time
 They can be used to prolong the ocular. residence time of drugs.
 In recent years, research has been employing silicon-based lences,Examples of drugs

35. 3)LACRISERT
 Lacrisert is a non-medicated, sterile, rod-shaped erodible insert which is made
from hydroxypropyl cellulose.
 It is doesn’t contain any preservative and is useful in the treatment of dry eye
syndrome.

36. 4) Microneedles-
 It is used to deliver drugs to posterior ocular tissues
It may reduce the risk and complication associated with intravitreal injections such as
retinal detachment, cataract haemorrhage ,
It may help to avoid blood retinal barriers and deliver therapeutic drug levels to retina
choroid.
These needles helps to deposit drugs or carries system into sclera or into the narrow
space present between sclera and choroid called suprachoroidal space
For intraocular delivery surface of microneedles is coated with drugs

37. 5) OCULAR IONTOPHORESIS
 It is non invasive and safe method for driving drug loaded nanoparticles including
medicine ions and macromolecules into the eye
 It overcomes barriers to ocular penetration of herbal nano particles
 These herbal nano particles stay in eye longer time and medicine is released in
sustained and prolonged manner
ADVANTAGES
 Relieves eye fatigue
 Improve blurred vision
 Improves Night Vision
 Relives dry eye symptoms

38. PARTICULATE SYSTEM
NANOPARTICLES
 A nanoparticle is a small particle that ranges between 1 to 100 nanometers in size.
 They are undetectable by the human eye, nanoparticles can exhibit significantly different physical and
chemical properties
 This helps in increasing the drug-corneal surface contact and thus
ocular bioavailability.
 These nanoparticles were found to increase the drug activity.
Nanoparticles are extremely small particles or structures that range in size
from 1 to 100 nanometers (one billionth of a meter). They can be made
from various materials such as metals, polymers, or ceramics.

39. MICROPARTICLES
Microparticles are small particles that are larger than nanoparticles but still
significantly smaller than a millimeter in size. Microparticles can be made from
various materials and find applications in drug delivery, cosmetics, and industrial
processes. Their larger size compared to nanoparticles allows for different
properties and uses in various fields.
 Microparticles are particles between 0.1 and 100 μm in size.
 Commercially available microparticles are available in a wide variety of
materials, including ceramics, glass, polymers, and metals
 Microparticles and Nano Particles are promising candidates for ophthalmic
drug delivery

40. OCUSERTS
 Prolonged drug release can be achieved using ophthalmic inserts (solid devices
placed in the eye) but the inserts must be removed when they are no longer
needed.
 Ocuserts are the new drug delivery systems which are designed in such a way
that they release the drug at predetermined and predictable rates thus
eliminating the frequent administration of the drug
Non Erodible Inserts: Ocusert
 It's Non-Erodible Ocular Controlled Drug Delivery System developed by
Alza Corporation.
 The Ocusert therapeutic system is a flat, flexible, elliptical device consisting of
two layers, enclosing a reservoir, designed to be placed in the inferior cul-de-
sac between the sclera and the eyelid and to release Pilocarpine continuously at
a steady rate for 7 days.

41. Structure Of Ocusert:-
The device consists of three layers…
I. Outer layer: ethylene vinyl acetate copolymer layer.
II. Inner layer: pilocarpine gelled with alginate main polymer
III. A retaining ring: of EVA impregnated with titanium di oxide.
Drug Reservoir : Pilocarpine, a para sympathomimetic agent for glaucoma
Carrier material: Alginic acid
Rate controller: Ethylene vinyl acetate copolymer
Energy Source: Concentration of Pilocarpine
Delivery Portal: Copolymer membrane
Annular ring: Impregnated with TiO2 For Visibility.
The Release Rate: 20-40 µg/h for 7 Days

42. OCUSERTS COMPONENTS

43. Advantages of Ocuserts
 A major advantage is that two disturbing side effects of the drug, miosis and
myopia, are significantly reduced, while reduction of intraocular pressure (IOP) in
glaucoma patients is fully maintained. Reduced local side effects and toxicity.
 Around the clock control of Intra ocular pressure (IOP).
 They improves the patient compliance by reducing frequency of dosing and lowers
systemic side-effects.
 Exclusion of preservatives.
 Increased shelf life with comparison to aqueous solutions due to absence of water.

44. Ocuserts Disadvantages /Limitations of Ocuserts
 Retention in the eye for the full 7days has to be maintained.
 Periodical check of unit.
 Replacement of contaminated unit.
 Expensive.
 The insert may be lost immediately.
 Sometimes the insert twists to form 'a figure eight', which diminishes the delivery
rate. A leakage may occur.
 Dislocation of the device in front of the pupil.

45. Ocusert Mechanism
 Ocuserts are also named as Diffusional insert.
 Ocusert system is a novel ocular drug delivery system based on porous membrane.
 The release of drug from diffusional Inserts/Ocusert is based on a diffusional
release mechanism.
 It consists of a central reservoir of drug enclosed in specially designed microporous
membrane allowing the drug to diffuse from the reservoir at a precisely determined
rate.
 Pilocarpine acts on target organs in the iris, ciliary body and trabecular meshwork.

46. Marketed forms of Ocuserts
The ocuserts are available in two marketed forms:
1. Pilo-20:-20 microgram/hour
2. Pilo - 40:-40 micrograms/hour
The Release Rate: The former delivers the drug at a rate of 20 µg/h for 7 days, and the
latter at a rate of 40 µg/h for 7 days.
The dimensions of the elliptical device are (for the 20 ug/h system): major axis:
13.4 mm, minor axis-5.7 mm, thickness-0.3 mm.
The membranes are the same in both systems, but to obtain a higher release rate, the
reservoir of the 40 µg/h system contains about 90 mg of di (2-ethylhexyl) phthalate as a
flux enhancer

47. CONCLUSION
 In the past two decades, ocular drug delivery research has emerged as a novel,
safe and patient complaint formulation delivery /techniques, which may
penetrate these barriers and maintain drug level in
 There novel formulations may help to surpass ocular, barriers and associated
side effects with. conventional topical drops
 They increase the residence time , sustain the drug release and enhance the
ocular bioavailability of therapeutics
 Further improvements are needed to achive effective and highly patient
complaint therapies

48. REFERENCES
 Controlled and Novel Drug NK Jain
 Novel Drug Delivery systems by Y.W. Chien
 Drug Delivery and Targeting (Anya, M. Hillary)
 Ocular Drug Delivering System by Pankaj Verma [SlideShare]
 Ocular Drug Delivery System by Mr Sagar Kishore Savale [ Slide Share]
 Ocular and Delivery: Present Innovations Future Challenges; Winde Aote