Ophthalmic preparations

Definition
Ophthalmic preparations refer to all pharmaceutical formulations intended for application to the eyes (either for therapeutic, prophylactic, diagnostic, or surgical purposes). These preparations are designed to be sterile, isotonic, non-irritating, and free of particulates, with physiological pH and osmolality to maintain ocular comfort and safety. They encompass a wide variety of drug classes and vehicles (e.g., drops, ointments, gels, inserts) formulated for treating conditions that affect the anterior or posterior segment of the eye.

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1. Categories of Ophthalmic Preparations

Ophthalmic preparations include the following major classes based on therapeutic indication:

A. Anti-infective agents

• Antibiotics: for bacterial conjunctivitis, keratitis (e.g., moxifloxacin, tobramycin)

• Antivirals: for herpetic keratitis (e.g., ganciclovir, trifluridine)

• Antifungals: for fungal keratitis (e.g., natamycin)

• Antiseptics: used occasionally in wound cleansing (e.g., povidone-iodine)

B. Anti-inflammatory agents

• Corticosteroids: reduce intraocular inflammation (e.g., prednisolone acetate, dexamethasone)

• NSAIDs: post-operative inflammation and pain (e.g., ketorolac, nepafenac)

C. Anti-glaucoma agents

• Beta-blockers: decrease aqueous humor (e.g., timolol)

• Prostaglandin analogs: increase aqueous outflow (e.g., latanoprost)

• Alpha-agonists, carbonic anhydrase inhibitors, and miotics

D. Lubricants and artificial tears

• Used for dry eye syndrome, contact lens irritation, or computer vision syndrome

• Examples: carboxymethylcellulose, hydroxypropyl methylcellulose, glycerin, sodium hyaluronate

E. Mydriatics and cycloplegics

• Used in diagnostic procedures and to treat uveitis

• Agents: tropicamide, phenylephrine, cyclopentolate, atropine

F. Anesthetics

• Local anesthetics for short procedures (e.g., proparacaine, tetracaine)

G. Anti-allergic agents

• Mast cell stabilizers: e.g., olopatadine, lodoxamide

• Antihistamines: e.g., ketotifen, azelastine

H. Immunomodulators

• Chronic inflammatory eye diseases (e.g., cyclosporine for dry eye, lifitegrast for inflammation)

I. Ocular diagnostic dyes

• Examples: fluorescein sodium, rose bengal, lissamine green for visualizing corneal defects

J. Surgical adjuncts and anti-VEGF agents

• Anti-VEGF injections (e.g., ranibizumab, aflibercept) for macular degeneration

• Viscoelastic agents, antibiotics, and anti-scarring drugs used in procedures

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2. Common Dosage Forms

Formulation	Description
Eye Drops (Solutions)	Most common; easy to use; short retention time
Suspensions	Contain insoluble particles; must be shaken; e.g., corticosteroids
Ointments	Longer retention; blurred vision; preferred at night or for lid conditions
Gels	Better bioavailability and contact time than drops
Emulsions	Oil-in-water for lipophilic drugs (e.g., cyclosporine emulsion)
Implants	Biodegradable or long-acting drug depots (e.g., Ozurdex)
Inserts	Small solid or gel-like forms placed in the conjunctival sac (e.g., Lacrisert)
Intravitreal injections	Directly into vitreous for retinal diseases (e.g., anti-VEGF therapies)
Subconjunctival injections	For depot delivery in severe inflammation or surgery

3. Formulation Considerations

Because of the sensitivity and anatomy of the eye, ophthalmic preparations must meet specific standards:

Property	Requirement
Sterility	Mandatory; usually autoclaved or sterile filtered
Isotonicity	Should be close to 0.9% NaCl (300 mOsm/kg)
pH	Ideally ~7.4 (range: 6.5–8.5) to avoid irritation
Viscosity	Enhances contact time (0.2% to 0.5% methylcellulose used)
Preservatives	Benzalkonium chloride (BAK), thiomersal, EDTA
Buffering agents	Maintain pH; e.g., phosphate, borate, citrate

4. Examples of Ophthalmic Medications by Class

Anti-Glaucoma

• Timolol – beta-blocker

• Brimonidine – alpha agonist

• Dorzolamide – carbonic anhydrase inhibitor

• Latanoprost – prostaglandin analog

Anti-Inflammatory

• Prednisolone acetate – corticosteroid

• Loteprednol etabonate – soft steroid

• Ketorolac tromethamine – NSAID

• Nepafenac – NSAID prodrug

Anti-Infective

• Moxifloxacin – fluoroquinolone

• Tobramycin – aminoglycoside

• Ganciclovir – antiviral gel for HSV

• Natamycin – antifungal

Dry Eye Treatments

• Cyclosporine (Restasis) – calcineurin inhibitor

• Lifitegrast (Xiidra) – LFA-1 antagonist

• Sodium hyaluronate drops

• Carboxymethylcellulose drops

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5. Common Conditions Treated

Condition	Ophthalmic Preparation Used
Bacterial conjunctivitis	Antibiotic eye drops (e.g., moxifloxacin, tobramycin)
Dry eye syndrome	Artificial tears, cyclosporine, lifitegrast
Allergic conjunctivitis	Antihistamines, mast cell stabilizers (e.g., olopatadine)
Uveitis	Corticosteroids (prednisolone), cycloplegics (atropine)
Open-angle glaucoma	Prostaglandin analogs, beta-blockers, carbonic anhydrase inhibitors
Postoperative inflammation	Steroids and NSAIDs
Herpes simplex keratitis	Ganciclovir gel, trifluridine drops
Macular degeneration (wet)	Ranibizumab, aflibercept (intravitreal)
Corneal edema or abrasion	Hypertonic saline, lubricants

6. Administration Guidelines

• Wash hands thoroughly before application

• Tilt head back and pull down lower eyelid to instill drop

• Close eye gently and press nasolacrimal duct to reduce systemic absorption

• Wait at least 5–10 minutes between multiple drops

• Use before ointments if both are prescribed

• Avoid touching the dropper tip to any surface

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7. Adverse Effects

Class	Possible Adverse Effects
Corticosteroids	↑ IOP, cataracts, secondary infections
NSAIDs	Burning, delayed healing, corneal melt (rare)
Antibiotics	Local irritation, hypersensitivity, resistance
Preservatives (e.g. BAK)	Ocular surface toxicity, allergic reactions, dry eye worsening
Prostaglandin analogs	Iris pigmentation, eyelash growth, uveitis

8. Special Populations

Population	Consideration
Pediatric	Use preservative-free if possible
Elderly	More prone to dry eye and glaucoma
Pregnant/lactating	Avoid systemic absorption; consult before use
Contact lens users	Avoid preserved products or remove lenses before use

9. Storage and Stability

• Store at room temperature unless refrigeration is required (e.g., latanoprost)

• Protect from light and moisture

• Discard multi-dose containers within 28 days after opening unless otherwise specified

• Single-use units should be discarded after one application

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10. Emerging Trends

• Preservative-free formulations (especially for chronic use)

• Nanoparticle drug delivery for improved corneal penetration

• Sustained-release ocular implants (e.g., Durysta for glaucoma, Ozurdex for uveitis)

• Gene therapy and biologics under development for retinal diseases

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11. Common Brand Examples

Generic Name	Brand Example	Class
Moxifloxacin	Vigamox	Antibiotic
Loteprednol	Lotemax	Corticosteroid
Cyclosporine	Restasis	Immunomodulator
Timolol	Timoptic	Beta-blocker (anti-glaucoma)
Latanoprost	Xalatan	Prostaglandin analog
Olopatadine	Pataday	Antihistamine
Ketorolac	Acular	NSAID
Proparacaine	Alcaine	Local anesthetic
Fluorescein	Fluor-I-Strip	Diagnostic dye