Local Ugandan Production of Stable 0.2% Chlorhexidine Eye Drops

Area of Science:

• Ophthalmology
• Pharmaceutical Sciences
• Infectious Diseases

Background:

• Fungal keratitis is a significant cause of visual impairment, particularly in tropical regions.
• Current treatments for fungal keratitis may be limited by the availability and stability of medications in resource-limited settings.
• Chlorhexidine (CHX) is an effective antiseptic, but its stability in ophthalmic preparations requires careful formulation.

Purpose of the Study:

• To develop and validate a reproducible protocol for preparing buffered chlorhexidine (CHX) eye drops (0.2% w/v).
• To ensure the stability and sterility of CHX eye drops suitable for use in low- and middle-income countries (LMICs).
• To facilitate the treatment of fungal keratitis in regions with limited pharmaceutical manufacturing capabilities.

Main Methods:

• Buffered CHX eye drops were prepared using sodium acetate buffer (pH 5.90-6.75) in amber glass containers.
• Stability was assessed over 21 months at 40°C (UK) and 30 months at ambient temperature (Uganda) using High-Performance Liquid Chromatography (HPLC).
• Sterilization was achieved via autoclaving (121°C) and water bath (100°C) methods.

Main Results:

• Acetate-buffered CHX eye drops maintained stable pH and concentration over the study period in both UK and Uganda.
• Unbuffered aqueous CHX solutions showed significant pH fluctuations, indicating degradation.
• Both autoclaving and water bath methods successfully sterilized the CHX eye drops.

Conclusions:

• A stable, sterile, buffered CHX eye drop formulation (pH 6.75) was successfully prepared and reproduced in both the UK and Uganda.
• The developed protocol is suitable for implementation in hospital or pharmacy settings with limited resources.
• This provides a cost-effective and accessible treatment option for fungal keratitis in LMICs.