The impact of the final rinse on the cytoxicity of critical products submitted for processing

Objective To assess the cytotoxicity of products subsequent to a cleaning process based on a validated standard operating procedure (SOP), and a final rinse with different types of water: tap, deionized, distilled, treated by reverse osmosis and ultra-purified. Method This was an experimental and laboratory study. The sample consisted of 130 hydrodissection cannulas, 26 per experimental group, characterized according to type of water used in the final rinse. The samples were submitted to internal and external contamination challenge with a solution containing 20% defibrinated sheep blood and 80% of sodium chloride 0.9%. Next, the lumens were filled with a ophthalmic viscosurgical device, remaining exposed for 50 minutes, and then were processed according to the validated SOP. Cytotoxicity was assessed using neutral red uptake assay. Results No cytoxicity was detected in the sample extracts. Conclusion The samples did not display signs of cytotoxicity, regardless of final rinse quality. The results obtained were reached by using only a validated cleaning operating procedure, based on the scientific literature, and on official recommendations and related regulation.