Sterility Assessment of Reclosable Ophtioles with Unpreserved Autologous Serum during Single-Day Use.

Background: According to the European Pharmacopoeia, multidose containers for eye drops must either contain antimicrobial agents, preservatives, or be fitted with filters or non-return valves to prevent microbial contamination after opening. Vials for single-day use do not have filters or non-return valves. The aim of this study is to demonstrate the safety of reclosable vials (ophtioles) containing unpreserved autologous serum eye drops (ASEDs) by evaluating their sterility during single-day use.

Material and methods: Two types of reclosable ophtioles were evaluated, one with a screw cap (Meise System, Heinz Meise GmbH, Schalksmühle, Germany) and the other one with a plug cap (COL System, BIOMED DEVICE S. R. L., Modena, Italy). Drop application over 12 hours was simulated in the laboratory following the manufacturer's instructions. For the Meise System, drops were applied at 2-hour intervals, while for the COL System, drops were applied at 1-hour intervals. Each application involved inoculating a chocolate-agar PolyViteX plate (PolyViteX, bioMérieux SA, Marcy-l'Étoile, France) with two drops spaced apart on the same plate and then incubating the plate. After 24 hours, a final inoculation was performed to check for sterility, and the plates were scored after 24 and 48 hours of incubation.

Results: In the Meise System test series, 12 vials were tested, providing 192 measurements over 12 hours with a 2-hour application interval. With the COL System, 16 vials were tested, resulting in 448 measurements with a 1-hour application interval over 12 hours. Neither the Meise nor the COL System showed contamination of any application after 24 hours of incubation. After 48 hours of incubation, two vials of the Meise System showed a contamination in one measurement, but subsequent applications were sterile again. In the COL System, nine measurements in seven vials were positive. In three of these vials, the last application at 24 hours showed contamination after 48 hours of incubation, where no further drops were applied.

Conclusion: The study confirms the sterility of ASEDs in two reclosable types of ophtiole systems during single-day use in laboratory-simulated conditions within 12 hours of application and 24 hours of incubation time. This is consistent with our several years of clinical experience of the absence of ocular infections caused by the use of ASEDs in the described ophtioles.