seminar on occular drug delivery systems

1. PRESENTED BY : MR. PRADIPKUMAR G. RATHOD
M. PHARM 1ST YEAR (1ST SEM.) (PHARMACEUTICS)
UNIVERSITY DEPARTMENT OF PHARMACEUTICAL SCIENCES,
R.T.M. NAGPUR UNIVERSITY, NAGPUR.
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2. Introduction :
Ocular administration of drug is primarily associated with the need to
treat ophthalmic diseases.
Eye is the most easily accessible site for topical administration of a medication.
Ideal ophthalmic drug delivery must be able to sustain the drug release and to
remain in the vicinity of front of the eye for prolong period of time.
Composition of eye
Water - 98%, Solid -1.8%, Organic element – Protein - 0.67%, sugar - 0.65%,
NaCl - 0.66% ,Other mineral element sodium, potassium and ammonia - 0.79%.
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3. Routes of occular drug delivery 3

4. Factors affecting intraocular bioavailability:
 1. Inflow & outflow of lacrimal fluids.
 2. Efficient naso-lacrimal drainage.
 3. Interaction of drug with proteins of lacrimal fluid.
 4. dilution with tears.
 5. Corneal barriers.
 6. Active ion transport at cornea.
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5. IDEAL OPHTHALMIC DELIVERY SYSTEM
 Good corneal penetration.
 Prolong contact time with corneal tissue.
 Simplicity of instillation for the patient.
 Non irritative and comfortable form
 Appropriate rheological properties
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OCULAR DRUG DELIVERY SYSTEMS
CONTROLLED
DELIVERY SYSTEMS
Implants
Hydrogels
Dendrimers
Iontophorosis
Contact lenses
Nano suspensions
Micro emulsions
Mucoadhesive
PARTICULATE
SYSTEMS
Nano particles
Micro particles
VESICULAR
DELIVERY SYSTEMS
Liposomes
Neosomes
Pharmacosomes
discomes
ADVANCED
DELIVERY SYSTEMS
Scleral plugs
Gene therapy
Stem cell
CONVENTIONAL
DOSAGE FORMS
SOLUTIONS
GELS
OINTMENTS
SUSPENSIONS
EYE DROPS
RETRO METABOLIC
DELIVERY SYSTEMS
Softdrug approach
Chemical delivery systems

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LIMITATIONS OF CONVENTIONAL
• Rapid precorneal elimination
• Solution drainage by gravity
• Frequent instillation is necessary
• Conjuctival absorption
ADVANTAGES OF AVANCED
DUG DELIVERY
• Sustained and/or controlled drug release
• Site-specific targeting
• Protect the drug from chemical or enzymatic hydrolysis
• Increasing contact time and thus improving
bioavailability
• Better patient compliance.

8. Use of mucoadhesives in ocular drug delivery
Polymereric mucoadhesive vehicle: Retained in the eye due to non-covalent bonding with conjuctival
mucine.
Mucine is capable of picking of 40-80 times of weight of water. Thus prolongs the residence time of drug
in the conjuctival sac.
• Mucoadhesives contain the dosage form which remains adhered to cornea until the polymer is degraded
or mucus replaces itself.
• Types-
1. Naturally Occurring Mucoadhesives- Lectins, Fibronectins
2. Synthetic Mucoadhesives- PVA, Carbopol, carboxy methyl cellulose, cross-linked polyacrylic acid
• Drugs incarporated in to this are pilocarpine, lidocaine, benzocaine and prednisolone acetate.
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• The polymer undergoes swelling in water,
• Entanglement of the polymer chains with mucin on
the epithelial surface.
• The un-ionized carboxylic acid residues on the
polymer form hydrogen bonds with the mucin.
• The water-swellable yet water insoluble
systems are preferred.
Mechanism of mucoadhesion

10. Vesicular system for ocular drug delivery
LIPOSOMES
• Vesicle composed of phospholipid bilayer enclosing aqueous
compartment in alternate fashion.
• Biodegradable, Non-toxic in nature.
• Polar drugs are incorporated in aqeous compartment while lipophilic
drugs are intercalated into the liposomemembrane
•Phospholipids used- Phosphotidylcholine, Phosphotidicacid,
Sphingomyline, Phosphotidyleserine, Cardiolipine.
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Endocytosis Fusion

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ADVANTAGES
•Drugs delivered intact to various body
tissues.
•Liposomes can be used for both hydrophilic
and hydrophobic drug.
•Possibility of targeting and decrease drug
toxicity.
•The size, charge and other characteristics
can be altered according to drug and desired
tissue.
DISADVANTAGES
•Their tendency to be uptaken by RI
system.
•They need many modification for drug
delivery to special organs.
•Cost

12. NEOSOMES
 Niosomes are non-ionic surfactant based multilamellar (>0.05μm), small
Unilamellar (0.025-0.05μm) or large unilamellar vesicles (>0.1μm) in which
an aqueous solution of solute(s) is entirely enclosed by a membrane
resulted from organization of surfactant macromolecules as bilayers
 STRUCTURAL COMPONENTS USED
• Surfactants (dialkyl polyoxy ethylene ether non ionic surfactant)
• Cholesterol.
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•ADVANTAGES:
•The vesicle suspension being water based offers greater patient compliance over oil based systems
•Since the structure of the niosome offers place to accommodate hydrophilic, lipophilic as well as ampiphilic
drug moieties, they can be used for a variety of drugs.
•The characteristics such as size, lamellarity etc. of the vesicle can be varied depending on the requirement.
•The vesicles can act as a depot to release the drug slowly and offer a controlled release.
•They are osmotically active and stable.
•They increase the stability of the entrapped drug
•Improves therapeutic performance of the drug by protecting it from the biological environment and
restricting effects to target cells, thereby reducing the clearance of the drug.
•DISADVANTAGES:
• Physical instability, Aggregation, Leaking of entrapped drug, Fusion.

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Advantages of vesicular systems
1. No difficulty of insertion as in the case of ocular inserts
2. No tissue irritation and damage as caused by penetration enhancers
3. Provide patient compliance as there is no difficulty of insertion as observed in the
case of inserts
4. The vesicular carriers are biocompatable and have minimum side effects
5. Degradation products formed after the release of drugs are biocompatable
6. They prevent the metabolism of drugs from the enzymes present at tear/corneal
epithelium interface
7. Provide a prolong and sustained release of drug

15.  CONTROLLED RELEASE OCULAR DEVICES
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INSERTS:
• Ophthalmic inserts are solid devices intended to be placed in the conjunctival sac and to deliver the
drug at a comparatively slow rate
• Increased ocular permeation with respect to standard vehicles, hence prolonged drug activity and a
higher drug bioavailability;
• Accurate dosing -theoretically, all of the drug is retained at the absorption site;
• Capacity to provide, in some cases, a constant rate of drug release.
• Nonerodible Inserts
OCUSERTS:
• Flexible, oval inserts
• Consists of a medicated core reservior prepared out of hydrogel polymer sandwiched between two
sheets of transperant lipophilic, rate controlling polymer like ethylene/vinyl acetate copolymer
membrane.

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CONTACT LENS :
• The most widely used Material is poly-2 hydroxyethylmethacrylate.
• Its copolymers with PVP are used to correct eyesight , hold and deliver drugs.
• Controlled release can be obtained by binding the active ingredient via
biodegradable covalent linkages.
Erodible Inserts
LACRISERT:
• It is a sterile ophthalmic insert use in treatment of dry eye syndrome.
• The insert is composed of 5mg of HPC in rod-shaped form about 1.27 mm
diameter by about 3.5 m long
MINIDISC:
• It is made up of counter disc with convex front & concave back surface in contact
with eye ball.
• Composition: silicon based pre polymer Hydrophillic or hydrophobic.

17. INTRAOCULAR INJECTIONS 17
• Micro needle used to deliver drug to posterior segment as an alternative to
topical route.
• It shows excellent in vitro penetration into sclera and rapid dissolution of
coating solution after insertion. In-vivo drug level was found to be
significantly higher than the level observed following topical drug
administration.
• To deliver anti-infective, corticosteroids and anesthetic product to achieve
higher therapeutic condition intraocularly, FDA approved intraocular
Injections includes miotics, viscoelastics, and anti-viral agents for intravitreal
injection

18. INTRAOCULAR IMPLANTS 18
• It employed to extend the release in ocular fluids and tissues particularly in the
posterior segment. It may be biodegradable and non-biodegradable.
• With implants, the delivery rate could be modulated by varying polymer composition.
• Implants can be in the form of solid, semi-solid or particulate based delivery systems.
These implants have been applied in the treatment of diseases affecting both anterior
and posterior segments of the eye.
• Implant containing gancyclovir or, anti-neoplastic agents is release drug over a 5 to 8
months.

19. CONCLUSION 19
• The main efforts in ocular drug delivery is to prolong the residence time of drugs
• The development of ophthalmic drug delivery systems is easy because we can easily target the
eye to treat ocular diseases the eye has specific characteristics such as eye protecting
mechanism, which make ocular delivery systems extremely difficult.
• The most widely developed drug delivery system is represented by the conventional and non-
conventional ophthalmic formulations to polymeric hydrogels, nanoparticle, nanosuspensions,
microemulsions, iontophorosis and ocular inserts.
• In future an ideal system should be able to achieve an effective drug concentration at the target
tissue for an extended period of time, while minimizing systemic exposure and the system
should be both comfortable and easy to use.

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