Properties, dosage forms in ophthalmic preparations. Action mechanisms, uses & adverse effects of cholinergic agents used in ophthalmic preparation..

1. BY: Syeda Aiman
Cholinergic agents usage in ophthalmologic preparation
Ophthalmic Preparation:
These are specialized dosage forms that are designed to
be administered
 Onto external surface of eye (Topical)
 Inside the eye (Intraocular)
 Adjacent to it (Periocular)
Properties of Ophthalmic preparation:
Sterility (main requirement)
Preservation
Particle limitations
pH
Stability
Eye comfort
Dosage forms in ophthalmic preparations:
Solutions, Suspensions
(Liquids)
Ointments, Gel
(Semi-solids)
Ocular inserts, Contact lenses
(Solids)
Injections, irrigation solutions
(Intraocular)

2. BY: Syeda Aiman
Cholinergic
agents
Direct
acting
Acetylcholine
Pilocarpine
Carbachol
Indirect
acting
Echothiophosphate

3. BY: Syeda Aiman
Action mechanisms of cholinergic agents used
in ophthalmic preparations:
Direct-Acting cholinergic agents:
(Acetylcholine, pilocarpine, carbachol)
These are the drugs that bind directly to cholinoceptors
and activate them;
muscarinic or nicotinic receptors.
Indirect-Acting cholinergic agent:
(Echothiophosphate)
It is an irreversible agent. It produces its
effect by inactivating acetylcholinesterase
enzyme (breaks down acetylcholine into
acetic acid and choline) thus increasing
acetylcholine level at the cholinergic
receptors.

4. BY: Syeda Aiman
 It is a synthetic choline ester.
 It is also called
parasympathomimeticbecause it
mimics the effect of acetylcholine
on both the muscarinic and
nicotinic receptors.
 It is applied to the conjunctiva.
 It is a direct acting miotic agent
(induce miosis). Miosis occurs
within 2-5 minutes after
application of intraocular solution
in form of injection.
 It belongs to miotic cholinergic
class of drugs. It is alkaloid and
has a positively charged
ammonium compound.
 It usually comes as a solution to
be instilled in eyes and as an eye
gel to be applied to the eyes
 Miosis occurs within 10-30
minutes after administration.
 It has been in use for 100 of years
for the treatment of glaucoma.
Carbachol
Pilocarpine

5. BY: Syeda Aiman
An ester of acetic acid and choline.
It is used as a parasympathetic preparation
for intraocular use.
Produce miosis in seconds which can last
upto 20 minutes.
It is a long-acting acetylcholinesterase
inhibitor.
It is administered as eye drops for topical use
It is used in ophthalmic preparations to
increase drainage of intra ocular fluid. Also
used as a miotic for treating glaucoma.
Acetylcholin
e
Echothiophosphate

6. BY: Syeda Aiman
Cholinergic agents in ophthalmic preparations
are used to:
Pilocarpine, Carbachol, Echothiophosphate
 Treat Glaucoma
(A condition in which intra
ocular pressure increases in
the eye which can lead to
gradual loss of vision).
These agents allow excess
fluid drainage from the eye
by contracting iris sphincter
muscle and ciliary muscle
leading to reduction in IOP.
Acetylcholine, Carbachol.
 Induce miosis in cataract surgery and other ophthalmic
surgeries when rapid miosis is required.
Miosis:
Excessive constriction of pupil leads to a condition called
miosis.

7. BY: Syeda Aiman
Adverse effects of cholinergic agents in
ophthalmic preparations:
 Ophthalmic cholinergic agents are often well-tolerated.
 Ocular and Systemic adverse effects that have been
reported with cholinergic agents tend to be rare and mild.
Ocular Systemic
Acetylcholine
 Clouding,
 corneal edema
(Rare)
Nausea
Vomiting,
Bradycardia,
Diarrhoea,
Salivation,
Perspiration
Pilocarpine
 Burning,
 Supraorbital
headache,
 lacrimation,
 ciliary spasm.
Carbachol
 Burning,
 corneal clouding,
 irritation
Echothiophosph
ate
(Anti-
cholinesterase)
 Blurred vision,
 browache,
 burning eyes,
 ciliary redness,
 conjuctival
redness/thickening,
 increased IOP

8. BY: Syeda Aiman
References:
istockphoto.com
researchgate.net
perfectlens.ca
Medicaid.utah.gov
ferapharma.com
dozepharmacy.com
sciencedirect.com