Hyaluronic Acid, Carboxymethylcellulose, Trehalose

Mechanism

💊 Commercial Names

Thealoz Duo, Aquoral, Optive, Artelac Splash, Viscofresh, Systane Ultra, Hylo-Comod.

🔬 Pharmacological Group

Viscoelastic polymers and osmoprotective surface disaccharides. Artificial tears.

🧪 Standard Formulations

Sterile ophthalmic eye drops in preservative-free single-dose containers or in one-way-valve multidose systems (ABAK, COMOD): hyaluronic acid 0.15% - 0.40%, trehalose 3.0%, carboxymethylcellulose (CMC) 0.5% - 1.0%.

Mechanism of Action

These highly hydrating polymers stabilize the layers of the tear film and protect the basal corneal epithelium:

• Viscoelasticity and Retention of Hyaluronic Acid: Sodium hyaluronate is a high molecular weight glycosaminoglycan polymer. Has a behavior non-Newtonian or pseudoplastic:
  1. During Blinking (High Shear Rate): Its viscosity decreases drastically under the friction force of the eyelid, distributing it evenly over the cornea and conjunctiva in a comfortable way, avoiding blurred vision.
  2. Between blinks (low shear): Its macromolecular helical structure expands, retaining water molecules up to 1000 times its weight, stabilizing the tear film and prolonging tear breakup time (TBUT).
• Bioadhesion of Carboxymethylcellulose (CMC): Anionic cellulose polymer that interacts with mucin glycoproteins of the basal corneal epithelium. By physically adhering, it protects the ocular surface from eyelid friction and facilitates the healing of stromal microerosions.
• Osmoprotective and Bioprotective Action of Trehalose: Natural disaccharide that directly penetrates the dehydrated epithelial cells of the cornea subjected to the stress of hyperosmolar dry eye:
  1. Prevention of Protein Denaturation: It forms a transient stabilizing viscoelastic gel around cellular proteins and membrane lipids, preventing their irreversible aggregation and structural denaturation induced by hyperosmolarity.
  2. Preservation of Cell Viability: Reduces damage due to oxidative stress and decreases conjunctival cell apoptosis, protecting the ocular surface from the inflammatory cycle.

Pharmacokinetics

Quantitative Ocular and Systemic Pharmacokinetics

Security

Contraindications

• Absolute: Documented hypersensitivity to any of the components of the tear substitute.
• Relative: Use of formulas with quaternary ammonium preservatives (benzalkonium chloride) in patients with severe dry eye or who require artificial tears to be instilled more than 4 to 6 times a day (the accumulated preservatives exacerbate corneal epitheliotoxicity, inducing iatrogenic punctate keratitis; in these cases the exclusive use of single-dose formulations free of preservatives).

Adverse Effects (ADR)

• Ocular Sites: Mild and transient blurred vision after immediate dural dosage (associated with the high viscosity of hyaluronate or CMC, it subsides after a few blinks); transient ocular itching; accumulation of crystalline or sticky debris on the lower eyelid edge in the morning.
• Systemic: Non-existent with an absolute clinical course.