Ocular drug delivery system is a method to deliver drugs to the eye to treat various eye conditions. This includes eye drops, ointments, and implants, which are designed to improve drug efficacy, minimize side effects, and provide sustained drug release. It is an important area of research and development in the field of ophthalmology, as it enables targeted and effective treatment of eye diseases. Here we have discussed about various preparations along with their evaluation parameters.
2. INTRODUCTION
GENERAL ANATOMY OF EYE
DRUG DELIVERY SYSTEM TO EYE
TYPES OF ODDS
ADVANTAGES
DISADVANTAGES
CONCLUSION
3. INTRODUCTION
DRUG DELIVERY SYSTEM-
It is a formulation or a device which brings the drug to a specific site of the body at a certain
rate to achieve an effective concentration at the site of drug action.
Mainly used to carry the drug components to the targeted part of the body without
reaching non target tissues and organs.
OBJECTIVES-
Increase patient compliance
Enhance drug efficacy
4. Cornea(Transparent part of the eye)
Iris(coloured part of the eye)
Pupil(the round opening at the centre of the
eye)
Lens(serves to transmit light to retina)
Vitreous body(clear gel fills the space
between the lens and retina)
Retina(contains millions of light sensitive
cells)
Optic nerve(a bundle of nerve carries visual
images)
5.
6. OCULAR DRUG DELIVERY
SYSTEM
Definition-
Ocular drug delivery system (ODDS) is a dosage form or system intended for
installing and administering the drug /medicine to eye against any disease or
disorder.
The most common disease or disorders that require ODDS are glaucoma, cataract,
infection on the ocular surface, inflammation, dry eye syndrome etc..
By the ODDS either the drug can be curable or provide a short term relief to various
diseases.
7. Non irritative and non-toxic
Prolong contact time with corneal tissue
Non greasy
Patient compliance
Must have good corneal penetration
9. TYPES
CONVENTIONAL DRUG DELIVERY SYSTEM
Eye drops
Ointments and gels
Ocuserts
VESICULAR SYSTEM
Liposomes
CONTROLL DRUG DELIVERY SYSTEM
Implants
Dendrimer
Nanosuspension
microneedles
NANOPARTICLES AND MICROPARTICLES
10. CONVENTIONAL DRUG DELIVERY SYSTEM-
EYEDROPS-
Applied directly to the surface of the eye
Contains saline and one or more medications
Less risk of side effects
Shelf life- no longer then three months after opening
Drawbacks- redness of eye, widened pupils
OINTMENTS AND GELS-
Prolonged drug contact time with external ocular surface can be achieved
Shelf life- 1 to 3 months
Drawbacks- blurring vision, matting of eyelids
11. OCUSERTS
Sterile preparations placed in conjunctival sac
Delivers drug at constant rate by diffusion mechanism
The device consist of three layers
1. Outer layer
2. Inner core
3. A retaining ring
Two types-
Insoluble Ocuserts
Soluble Ocuserts
12. RESERVOIR SYSTEM
The reservoir system can release drug
either by diffusion or by an osmotic
process.
It mainly contains a liquid, a gel, a
colloid, a semisolid, a solid matrix and
a carrier containing drug.
The carriers are made up of
hydrophobic, hydrophilic, organic,
natural or synthetic polymers.
MATRIX SYSTEM
The matrix system can be represented
by contact lens.
It comprises of a covalently cross-
linked polymer that forms a three
dimensional network capable of
retaining water, aqueous drug solution
or solid components.
The hydrophilic or hydrophobic
polymers swells by absorbing water.
13. Offers the advantages of being entirely soluble
Need not to be removed from the site of application
Natural polymer-
Collagen is mainly used
As the collagen dissolves, the drug binds between the collagen is gradually released.
Synthetic and semi-synthetic polymer-
Semi-synthetic polymers such as cellulose derivatives are mainly used.
14. VESICULAR SYSTEM
LIPOSOMES-
It is used for the effective drug delivery to the posterior chamber of the eye.
These are biodegradable and biocompatible lipid vesicles made up of natural lipids
and about 25-10000 nm in diameter.
They are having an intimate contact with the corneal and conjunctival surfaces which
is desirable for drugs that are
poorly absorbed
With low partition coefficient
Poor solubility
With high molecular weights
They can contain a wide range of both hydrophilic and hydrophobic therapeutic
agents.
15. Continue…
Liposomes have good effectiveness for
both the anterior and posterior segment
of eye.
LIMITATIONS-
Chemical instability
Oxidative degradation of phospholipids
The cost of natural phospholipids
16. Continue…
NIOSOMES-
Non ionic surfactant vesicles that have potential
applications in the delivery of hydrophobic and
amphiphilic drugs.
They are chemically as stable as liposomes and can
entrap both hydrophobic and hydrophilic drugs.
Non toxic and don't require any special handling
technique.
17. CONTROL DRUG DELIVERY SYSTEM
IMPLANTS-
• It is of two types
• Biodegradable implants
• Non-biodegradable implants
• Biodegradable implants- Implants containing biodegradable polymers and here the
drug is released during polymer degradation.
• Non-biodegradable implants- Can be presented in form of matrix and reservoir
system.
• Matrix system- here the drug is dispersed homogenously in the polymeric matrix.
• Reservoir system-here the drug is surrounded by a non degradable membrane which can control
the diffusion of drug.
18. The dendrimer generally means a synthetic
polymer with a structure of repeatedly
branching chains.
It can enhance the drugs water solubility and
bioavailability.
They also have permeable enhancer
properties.
Here is a schematic representation of drug
entrapped in dendrimers.
19. NANO-SUSPENSIONS
They basically enhance the rate and extent of drug
absorption and also increase the duration of drug effect.
There are various techniques used for the commercial
preparation of the nanosuspensions.
MICRONEEDLES
They had shown prominent in-vitro penetration in to sclera
and rapid dissolution of coating solution after insertion.
20. NANOPARTICLES AND
MICROPARTICLES
The maximum size limit for nanoparticles are 5-10mm above which itching occurs
upon installation.
The nanoparticles are prepared by using various bio adhesive polymers to provide
sustained effect to the entrapped drugs.
These are mainly designed to
Overcome the barriers
Increase the drug penetration at the target site
Increase the drug retention for controlled delivery.
21. EVALUATION OF ODDS
Thickness of the film
Drug content uniformity
Uniformity of weight
Percentage moisture absorption
Percentage moisture loss
INVITRO EVALUATION METHODS-
Bottle method
Diffusion method
Accelerated stability study
22. THICKNESS OF THE FILM-
Measured the thickness at different points and the mean value is calculated.
DRUG CONTENT UNIFORMITY-
The cast film cut at different places and tested for drug as per monograph.
UNIFORMITY OF WEIGHT-
Three patches are weighed.
23. PERCENTAGE MOISTURE ABSORPTION-
Here the ocular films were weighed and placed in a desiccator containing
1. 100ml of saturated solution of aluminum chloride
2. 75% of humidity was maintained.
After 3 days the ocular films were reweighed and percentage moisture absorbed is
calculated.
initial weight –final weight
Percentage moisture absorbed= x 100
initial weight
24. PERCENTAGE MOISTURE LOSS-
Ocular films are weighed and kept in desiccator containing anhydrous calcium
chloride.
After 3 days, the film were reweighed and percentage loss in moisture is calculated
using ..
initial weight – final weight
Percentage moisture loss= x 100
initial weight
25. BOTTLE METHOD-
Here the dosage forms are placed in a bottle containing dissolution medium
maintained at specified temperature and pH.
The bottle is then shaken and sample is taken at appropriate intervals and analyzed.
DIFFUSION MEHOD-
Drug solution is placed in donor compartment and buffer medium is placed in
between donor and receptor compartment.
Drug diffused in receptor compartment is measured in different time intervals.
26. Carried out to predict the breakdown that may occur over period of time.
Here the dosage form is kept at elevated temperature or humidity or intensity of light
or oxygen.
Then after regular interval of time the sample is taken and analyzed for drug content.
From the result graphical data is plotted and self life and expiry date are determined.
27. ADVANTAGES OF ODDS
Improve bioavailability by increasing ocular resistance
Providing a prolonged drug release
Increase self life with respect to aqueous solutions
Less visual and systemic side effects
Better patient compliance
Having quick absorption and effect
28. DISADVANTAGES
Foreign body sensation
High cost
Unwanted migration of the implants inside the eye
Interference with vision
Difficulty in the insertion of ocular implants
Necessity of using preservative
29. CONCLUSION
The controlled ocular drug delivery systems increase the efficacy of the drug
by reducing its wastage and by enhancing absorption by increasing contact
time of drug to the absorbing surface.
This improve patient compliance by reducing the frequency of dosing.
As they reduce the frequency of dosing, the adverse effect of the drug is
minimalized.
30. How vision works-
https://www.youtube.com/watch?v=s0B_CiOEXSI
Detailed explanation of ocular drug delivery system-
https://www.youtube.com/watch?v=46luf1uwwfE&t=3s
https://www.youtube.com/watch?v=4L8kUNdtRnM
https://www.youtube.com/watch?v=Vd2zRLWQ1sg
Ocuserts-
https://www.youtube.com/watch?v=_OOFuyjuW6s