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

The research article explores how storing a 1% solution of the drug Voriconazole in a constant-rate infusion (CRI) pump impacts its stability and sterility. The researchers found that the drug solution is unstable in the pump, particularly at temperatures between 23 to 40 °C, and is instead stable when stored in a commercial glass vial under the same conditions.

Methodology

• Nine vials of Vfend® I.V., a 1% solution of voriconazole, were prepared. Each solution was then split with about half used to prime a CRI pump with an attached subpalpebral lavage (SPL) system (CRI/SPL unit) and the remaining half kept in the vial it came in.
• The units and corresponding vials were stored at three distinct temperatures: 23 °C, 33 °C, and 40 °C. The CRI pump operated for seven days while the vials were stored for thirty days.
• Fungal and aerobic bacterial cultures were taken on the first and last day of storage for each container. Regular samples were taken to measure voriconazole concentration via high-performance liquid chromatography.

Results

• Throughout the experiment, no bacterial or fungal contamination was discovered in any of the solutions at any point.
• All solutions stored in the glass vials remained stable for the duration of the experiment.
• However, multiple CRI/SPL units became blocked with crystallized voriconazole, indicating instability of the solution in the pump.
• There was a significant increase in voriconazole concentration after passage through the CRI/SPL units, suggesting that the pumps influenced the solution’s chemical stability.

Conclusion

• The researchers concluded that a 1% solution of voriconazole is incompatible for use in a CRI/SPL unit at temperatures ranging from 23 to 40 °C due to instability and tendency to crystallize.
• On the other hand, when a 1% solution of voriconazole is stored in a commercial glass vial, it remains stable even at high temperatures (up to 40 °C) for a period of up to 30 days.