Intraocular penetration of netilmicin

Area of Science:

• Ophthalmology
• Pharmacology
• Drug Delivery

Background:

• Aminoglycosides are crucial antibiotics in ophthalmic practice.
• Understanding intraocular penetration is key for effective antibiotic therapy.
• Netilmicin is an aminoglycoside with potential ophthalmic applications.

Purpose of the Study:

• To evaluate the intraocular penetration of netilmicin.
• To compare netilmicin's ocular penetration after intramuscular vs. subconjunctival injection.
• To determine therapeutic aqueous humor levels and duration following different administration routes.

Main Methods:

• A study involving 102 patients undergoing elective cataract surgery.
• Intramuscular injections of netilmicin (1.5 mg/kg single or two doses).
• Subconjunctival injections of netilmicin (12.5 mg or 25 mg).
• Measurement of serum and aqueous humor netilmicin levels.
• Assessment of drug levels and duration in the anterior chamber.

Main Results:

• Intramuscular netilmicin yielded therapeutic serum levels but low aqueous levels (<2.4 µg/mL).
• Subconjunctival netilmicin achieved significantly higher aqueous levels (up to 36 or 85.6 µg/mL).
• Therapeutic anterior chamber levels persisted for 7–9 hours after subconjunctival injection, dose-dependent.
• Ocular penetration was comparable to other aminoglycosides, despite variable aqueous levels.

Conclusions:

• Subconjunctival injection is superior for achieving therapeutic intraocular netilmicin concentrations.
• Netilmicin demonstrates effective ocular penetration and sustained anterior chamber levels via subconjunctival route.
• Both administration routes were well-tolerated, with no major complications observed.