This document summarizes various ocular drug delivery systems including conventional eye drops and novel controlled release systems. It discusses the need for controlled delivery to overcome issues with frequent dosing from drops and increase ocular bioavailability. Approaches to optimization include improving contact time, permeability and site specificity. Recent controlled delivery systems described are polymeric solutions, phase transition, mucoadhesive, collagen shields, pseudolattices, penetration enhancers and iontophoresis. Matrix, capsular and implantable pump devices are also summarized.

1. DEPARTMENT OF
INDUSTRIAL PHARMACY
A
SEMINAR
ON
OCCULAR DRUG DELIVERY SYSTEM
SONAM M.GANDHI
FIRST M.PHARM

2. Introduction
 A drug delivery system ideally should deliver a
specified amount of medication to site of action at
an appropriate time and date.
 Novel ocular drug delivery system are designed
in order to over come various drawbacks of
conventional medications and having improved
patient convenience and better therapeutic
efficacy.
 Ocular administration of the drug is primarily
associated with need to treat ophthalmic diseases.
 Systemic action by using eye as a portal is
generally avoided in order to prevent the risk of eye
damage from high blood concentration of drug not
intended for eye.

3. EVALUATION OF OCULAR DELIVERY
SYSTEM
 The conventional ocular dosage forms for the
delivery of drugs are:
i. Eye drops,
ii. Eye ointments and
iii. Eye suspension.

4. Requisites of controlled ocular delivery
system:-
 To over come the side effects of pulsed dosing
(frequent dosing and high concentration)
produced by conventional dosage form.
 To provide sustained and controlled drug delivery .
 To provide comfort and compliance.
 To provide prolonged drug release.
 To increase the ocular bioavailability of drug by
increasing corneal contact time. This can be
achieved by effective coating or adherence to
corneal surface.

5. Approaches made towards optimization of
ocular delivery system:-
1) Improving ocular contact time.
2) Enhancing corneal permeability.
3) Enhancing site specificity.

6.  The following recent trends of dosage forms are in
vogue:-
1. Controlled ocular delivery system:
i. Polymeric solution
ii. Phase transition system
iii. Mucoadhesive / bioadhesive dosage form
iv. Collagen shields
v. Pseudolatics
vi. Ocular penetration enhancers
vii. Ocular ion phoresis.

7. 2. Ocular drug delivery devices:
1)Matrix type drug delivery systems.
1. Hydrophilic soft contact lenses
2. Soluble ocular inserts
3. Scleral buckling materials.
2)Capsular type drug delivery system.
1. Ocuserts and releated devices
2. Implantable silicone rubber device
3)Implantable drug delivery pumps.
1. Osmotic mini pump and implantable infusion system
4)others
1. Ocufit and lacrisert
2. Minidisk ocular therapeutic system
3. New ophthalmic delivery system.

8. 1.Controlled ocular delivery system
I. Polymeric solution :
The addition of polymers like methyl cellulose, poly vinyl
alcohol, hydroxyl propyl methyl cellulose and poly vinyl
pyrolidine to the eye drop solutions increases the corneal
penetration of drug .
ll. Phase transition system :
These are the liquid dosage forms which shift to the gel
or solid phase when instilled into the cul-de-sac.
There are three types of phase transition system :
a. Temperature dependent.
b. PH triggered.
c. Ion activated.

9. III. Mucoadhesive / Bioadhesive dosage form:
Any polymer solution or microparticle suspension
placed in the eye first encounter mucin at the
cornea and conjunctival surface. This polymer
adheres to mucin, t he interaction reffered to as
mucoadhesion.
mucoadhesives polymer are usually
macromolecular hydrocolloides with numerous
hydrophilic functioal groups. These groups are –
COOH, -OH, CONH2 and SO4²¯.
A good bioadhesive should exhibit a near zero
contact angle to allow maximal contact with
mucin coat.

10. IV. COLLAGE SHIELDS :
Collagen is the structural proteins of the bones, tendons
ligaments and skin and comprises more then 25% of
total body protein in mammals. Collagen is the main
constituents of food grade gelatin and derived from
intestinal has several biomedical application.
V. Pseudolattices :
Are a new class of polymeric colloidal dispersions and
films foaming agents used for topical application into
the animal’s and the human being used for sustaining
the drug activity in vivo

11. Vi Occular penetration enhancers:
like actin filament inhibitors, surfactants inhibitors,
bile salts, chelators and other compounds have
been used to increase the bioavailability of topically
applied peptide and protiens which are otherwise
poorly absorbed due to unfavourable unfavourable
molecular size, charge, hydrophilicity.
Vii Occular iontophoresis:
Is a process in which the direct current drivse
ions into the cell or tissue.

12. 2. CONTROLLED DRUG DELIVERY DEVICES.
A) MATRIX-TYPE DRUG DELIVERY SYSTEM:
i. Hydrophilic soft contact lenses:
Are easy to fit and tolerated and rapidley tolerance, hydrophilic soft contact are
more popular for correction of hydrogels like PHP copolymer.
The ability of available disposable soft contact lenses to absorb various ocular
therapeutic agents and release them. After a 2hr or 4hr presoaking time, they
measured the amount of drug released into fresh saline baths for upto 3hr.
ii. Soluble ocular inserts:
Are thin, elastic, oval plates and made from polymers and co-polymers of
polyacrylamide, ethylacrylate and vinyl pyyrolidone. When soluable ocular
inserts inserted into a conjunctivl sac, it absorbs tears rapidly, swells and
dissolves in about 30-90min releasing the active subsance in a controlled
manner.
iii. Scleral buckling materials:
Are used in retinal detachment surgery as they cause postoperation. So to
prevent this complication, scleral buckling matrials can be made to absorb an
antibiotic. Two common scleral buckling materials, gelatin film and solid
silicon rubber.

13. B) CAPSULAR TYPE DRUG DELIVERY SYSTEM:
i. Ocuserts and related devises:
The system consists of pilocarpine and alginic acid core sandwiched
between 2 thin transparent , rate controlling ethylene- vinyl acetate
copolymer membrane.
eg: pilo-20 contains 5mg drug are used.
pilo- 40 contains 11mg drug.
ii. Implantable silicone rubber device:
the constant release rate implantable silicone rubber device for
hydrophobic drug like BCNU an intraocular maligancy agent.
C) IMPLANTABLE DRUG DELIERY PUMPS:
i. Osmotic minipump and implantable infusion system: the osmotic
minipump is a useful implanatable drug delvery system with a constant
drug delivery rate with a pumping duration of upto 2 weeks. The
implantable infusion system , the pumping force is generated by an
expending fluid at body temperature.
The implantable devices and osmotic minipump, which have developed
and used as drug peelet coated with PVA and ethylene vinyl acetate and
polysulfone capillary fiber.