This document discusses different ophthalmic dosage forms including liquids, semisolids, and solids. It focuses on ophthalmic ointments, which are semisolid formulations that provide longer drug contact time and bioavailability. It also describes non-erodible and erodible ocular inserts, highlighting examples like the pilocarpine ocusert and lacrisert. The pilocarpine ocusert is an elliptical membrane that controls drug release over time, while the lacrisert erodes gradually to prolong its effects. Soft contact lenses can also be used to prolong drug delivery but have disadvantages related to contamination risks.

1. Types of Ophthalmic Dosage Forms
Liquid
Dosage Form
Solution
Suspension
Emulsion
Powders for
reconstitution
Semisolid
Dosage Form
Ointment
Solid Dosage
Form
Insert

2. Semi solid Dosage Forms
Ophthalmic Ointment
 Interfere with vision unless use is limited to bed
time instillation.
 Often used as adjunctive night time therapy, with
eye drops administered during the day.
 Longer contact time and greater total drug bioavailability,
with slower onset & much more time to reach peak
absorption.
 Vehicle is usually a mixture of mineral oil & white
petrolatum.
Mineral oil is added to:
a)reduce the melting point.
b)Modify the consistency.

3. Petrolatum-based ointments are:
a)Bland.
b)Inert nature
which make them suitable vehicle
for moisture -sensitive drugs.

4.  Ointments used as vehicles for antibiotics,
sulfonamides, antiviral, antifungal, & anti-
inflammatory corticosteroids.
 Anesthesiologists may prescribe the
ointment vehicle for the surgical patient
undergoing general anesthesia to prevent
severe and painful dry eye conditions.
 The anhydrous petrolatum base may be
made more miscible with water through the
use of an anhydrous liquid lanolin
derivative , then aqueous drug solution can
be incorporated.

5. How to use ophthalmic ointment?
1. Wash hands.
2. Remove cap from the tube.
3. With one hand, gently pull the lower eye lid down.
4. While looking up, squeeze a small amount of
ointment (about ¼ to ½ inch) inside lower lid. Be
careful not to touch tip of tube to eye, eyelid,
fingers, etc.
5. Close eye gently and roll eyeball in all directions
while eye is closed. Temporary blurring may occur.
6. The closed eye lid may be rubbed very gently by a
finger to distribute the drug throughout the fornix.
7. Replace cap on tube.

6. Types of Ophthalmic Dosage Forms
Liquid
Dosage Form
Solution
Suspension
Emulsion
Powders for
reconstitution
Semisolid
Dosage Form
Ointment
Solid Dosage
Form
Insert

7. Solid Dosage Forms
Ocular Inserts

8. Non erodible Ocular Inserts
 In 1975, the first controlled release topical
dosage form was marketed in the United
States by the Alza Corporation which was
pilocarpine ocusert.
 Pilocarpine ocusert is an elliptical- shaped
membrane which is soft & flexible designed
to be placed in the cul-de-sac between the
sclera & the eye lid .

9. Intranasal and intraoccular drug delivery 03/10/2009
Intraocular Drug Delivery
1,4. Rate controlling
ethylene-vinyl acetate
copolymer
membranes
2. Annular opaque
ring
3. Drug reservoir
Pilocarpine ocusert consists of :
- A rate controller, ethylene vinyl acetate (EVA) copolymer
membrane.
- A delivery portal, the copolymer membrane.
- Drug reservoir, pilocarpine, carrier material, alginic acid.

10. •Design 0f ocusert:
The ocusert is sterile, oval in shape & flexible,
It is made of a central core or reservoir which contains the
drug embedded in an alginic acid gel-like base,
the drug reservoir is surrounded by a rate-limiting or
controlling membrane made of ethylene vinyl acetate co-
polymer which gives a steady and controlled drug release for
a certain period of time.
The device is bordered by a white annular ring consisting of
ethylene vinyl acetate co-polymer impregnated with titanium
dioxide (a powdered pigment) that darkens the borders of the
ocusert. The border makes the ocusert easier for the patient
to visualize.

11. Ophthalmic Inserts
Pilocarpine Insert
 The release rate of pilocarpine from this system is given by:
 (Fick’s law)
Where
dm/dt is the release rate
D is the diffusion coefficient of the drug in the membrane
K is the partition coefficient that is the ratio of drug concentration at
equilibrium inside the membrane to that outside the membrane
ΔC is the difference of the drug concentration between the inside and the
outside walls of the membrane (concentration gradient)
(The driving force of the release is the concentration of the drug in the
reservoir)
A is the area
h is the thickness of the system
Under routine conditions, the concentration of the drug in the tears is
negligible (2-3 µg/mL) compared to that inside the membrane, which is
essentially the solubility of the drug, so the equation can be rewritten:
h
C
ADK
dt
dm 

h
ADKS
dt
dm


12. Pilocarpine ocusert
•Used to treat Glaucoma because it reduces intraocular pressure
• It is designed to release pilocarpine at a controlled required rate
(for example, 20 micrograms hour or 40 microgram or 80
microgram per hour), for a certain period of time (like 7 days), after
7 days the ocusert is removed & replaced by a new one, so it’s more
convenient than pilocarpine eye drops which is used 4 times a day
normally.
Advantages over drop therapy for the glaucoma patient:
Exposes the patient to only one-fourth to one-eighth the amount of
pilocarpine compared to drop therapy. (reduced local side effects &
toxicity.)
It provides a continuous around – the clock- control of IOP.
Patient convenience & improved compliance.(administered only once
per week.)

13. Erodible Ocular Inserts
 Why ?
1. They do not have to be removed at
the end of the therapy
2. Increase retention time
3. Increase penetration of the drug
4. Prolonged effect
Ex. Lacrisert

14. Lacrisert used to treat dry eyes, keratitis,
and decreased corneal sensitivity
It contain 5 mg of HPMC in a rod-
shaped of about 1.27mm
diameter and 3.5mm long, no
preservative since it is
anhydrous.
It imbibes water from the tears
and forms a gel-like mass after
several hours, which gradually
erodes as the polymer dissolves, it
thickens the tear film and
provides increased lubrication. it
used once or twice daily

15. Soft Contact Lens
Soft hydrophilic contact lens of the hydroxyl ethyl
methacrylate (HEMA) polymer to prolong delivery of
pilocarpine.
 Lens is presoaked in a sterile unpreserved
solution of the drug.
 Placed in the eye over the cornea for a period of
time, usually few minutes to several hours to
increase the amount of drug absorbed or to prolong
the duration of effect.(reduce the frequency of drug
instillation & give diurnal control to the treatment of glaucoma)

16. • Disadvantages: Uncontrolled nature to the
release of drug from it.
Potential for increased risks of contamination
since unpreserved drug solutions must be used
& the patient must disinfect the lens himself.
 Example of contact lenses
 The Bionite lens which is made from
hydrophilic polymer (2-hydroxy ethyl
methacrylate ) has been shown to
produce a greater penetration of
fluorescein.