Stability of 1% voriconazole solution in a constant‐rate infusion pump for topical ocular delivery to horses

OBJECTIVE: To establish the effect of storage in a constant‐rate infusion (CRI) pump on the sterility and stability of voriconazole 1% solution. PROCEDURE: Nine vials of voriconazole (Vfend® I.V.) 1% solution were prepared. Approximately half of each solution was used to prime a commercially available CRI pump with attached subpalpebral lavage system (CRI/SPL unit) with the remaining solution stored in the commercial glass vial. Three CRI/SPL units and their three corresponding vials were stored at one of three temperatures: 23 °C, 33 °C, and 40 °C. The CRI pumps ran for 7 days, and the vials were stored for 30 days. Fungal and aerobic bacterial cultures were performed on the first and last day of the storage period for each vessel. Samples were obtained at regular intervals for determination of voriconazole concentration using high‐performance liquid chromatography. RESULTS: No bacterial or fungal contamination was identified in any solution at any time point. All solutions stored in the commercial glass vial remained stable throughout the study period. Multiple CRI/SPL units became blocked with crystallized voriconazole. There was a significant increase in voriconazole concentration after passage through the CRI/SPL units. CONCLUSIONS: Voriconazole 1% solution is not compatible for use in a CRI/SPL unit at temperatures between 23 and 40 °C. Voriconazole 1% solution is stable in the commercial glass vial when stored at controlled temperatures as high as 40 °C for up to 30 days.