High Hydrostatic Pressure as Sterilization Method for Drug-Loaded Intraocular Lenses

Sterilization is a key step in the manufacturing of drug-loaded intraocular lenses (IOLs). Two of the most used methods to sterilize commercial IOLs are steam heat and gamma radiation. However, when the IOLs are loaded with drugs, the adequacy of those methods must be questioned because sterilization may affect the activity of the drugs and/or the drug release. Recently, high hydrostatic pressure (HHP), which is increasingly used in the food industry, has been applied in the sterilization of gels for medical applications. The objective of this work was to assess the performance of HHP in the sterilization of a commercial acrylic material used for the production of IOLs, both without and with loaded drugs. Bare samples and samples loaded with an antibiotic and two anti-inflammatories were tested, and the results were compared to those obtained with conventional sterilization methods. HHP not only sterilized highly contaminated samples but also enhanced drug loading and did not affect significantly the hydrogel properties. Gamma radiation degraded the drugs in solution; thus, it is adequate only for dry sample sterilization. Steam heat did not affect the release profiles but cannot be applied to temperature-sensitive drugs. We concluded that HHP may advantageously substitute steam heat and gamma radiation in the sterilization of drug-loaded IOLs.