Stability of voriconazole 10 mg/mL ophthalmic solution during 90 days

Abstract Objectives Fungal keratitis is a rare but severe cause of infectious keratitis and can lead to blindness. To cure fungal keratitis, antifungal like voriconazole eye drops must be immediately administered. As no brand is available on the market, voriconazole ophthalmic solution is compounded in hospital pharmacies using voriconazole powder for intravenous infusion. The aims of our study were to both assess the physico-chemical and microbiological stability of eye drop solutions stored at +2 to 8 °C. Two different High-Density-Polyethylene (HDPE) eye drop dispensing containers were assessed, one with a sterility preserving cap Novelia®(Nemera) and the other without sterility preserving cap both provided by CAT laboratory. In addition microbiological quality was assessed during 15 days simulated patient use. Methods Multiple batches of voriconazole 10 mg/mL eye drops were prepared and stored at +2 to 8 °C to study their stability over 90 days. All analyses were performed in triplicate. Physical stability was determined, pH determination, osmolarity measurement, and a particle count test was also performed. A high performance liquid chromatography (HPLC-UV) stability indicating method was used to determine chemical stability of the ophthalmic solution over 90 days of storage. For microbiological stability, a sterility test was performed using closed membrane filtration method (Steritest®, Merck Millipore) at D0, D90 and D90+15 days after simulated administration of eye drops (D90+15). Results For both containers, no variation of visual aspect, pH, osmolality, particle count and final concentration were observed. No microbiological growth was observed after 90 days of storage. At the end of the simulated administration period (D+15), unconstant microbiological growth was only observed in HDPE vials without sterility preserving cap, whereas HDPE vials with a sterility preserving cap Novelia®(Nemera) remained sterile. Conclusions Voriconazole 10 mg/mL ophtalmic solution was stable during 90 days at +2 to 8 °C in lightproof HDPE vials without sterility preserving cap and HDPE vials with a sterility preserving cap Novelia®(Nemera). However, vials with classical cap which are not airtight systems, may microbiologically contaminated during patient’s use than vials with Novelia® cap thanks to their innovative valve system.