Stability study including impact of temperature excursions on a new vancomycin eye drop formulation

Area of Science:

• Ophthalmology
• Pharmaceutical Sciences
• Microbiology

Background:

• Severe bacterial keratitis necessitates highly concentrated antibiotic eye drops.
• These specialized eye drops are not commercially available and must be compounded by hospital pharmacies.
• Stability and efficacy of compounded eye drops under various storage conditions are critical.

Purpose of the Study:

• To develop a novel, preserved 50 mg/mL vancomycin eye drop formulation.
• To assess the physicochemical and microbiological stability of the vancomycin eye drops.
• To evaluate the preservative efficacy and stability during temperature excursions.

Main Methods:

• Vancomycin concentration was quantified using validated high-performance liquid chromatography (HPLC).
• Physicochemical properties (limpidity, particles, pH, osmolality) were assessed.
• Sterility, antimicrobial preservative efficacy, and stability under simulated storage and temperature excursion conditions were tested.

Main Results:

• The vancomycin eye drops maintained specified concentrations and physicochemical properties after 3 months of freezing and subsequent refrigerated storage.
• The formulation remained stable for 7 days at 2°C–8°C after a transient temperature excursion to 25°C for up to 12 hours.
• No microbial contamination was observed during simulated daily use for 7 days.

Conclusions:

• The developed 50 mg/mL vancomycin eye drop formulation demonstrates excellent stability.
• The formulation is robust against temperature fluctuations, ensuring its suitability for hospital compounding and clinical use.