Evaluation of ultraviolet irradiation efficacy in an automated system for the aseptic compounding using challenge test

Objective Ultraviolet (UV) irradiation efficacy in the intravenous compounding robot APOTECAchemo was evaluated to define the best operative conditions in terms of sterility and time optimization. Design The challenge test was used against Pseudomonas aeruginosa , Escherichia coli , Staphylococcus aureus , Bacillus subtilis spores and Candida albicans . Inoculated plates were placed inside the robot and irradiated for different times. Microbial air and surface quality inside the equipment were monitored utilizing settle and contact plates, swabs. Results After 4 h, no microorganisms were viable with killing rates ranging from 5- to 7-log for different microorganisms after 1 h of exposition. In confirmation of the efficacy of the UV irradiation program adopted, the microbial monitoring inside the equipment always gave negative results. Conclusions This is the first exhaustive investigation of UV irradiation efficacy in the aseptic pharmaceutical production. We demonstrated that UV irradiation plays an essential role in maintaining the sterility condition of the workplace inside the APOTECAchemo and assuring the standards for aseptic manufacturing of medicinal drugs, as required for Class A clean areas. A 4-h UV irradiation also ensures sterility in the case of very resistant microorganisms and in the presence of high microbial charge (108 CFU/ml), but a killing rate of 5 or more is already recorded after the first hour of exposition. The results provide useful information for the best operative conditions in terms of both sterility and time optimization, not only for the automated compounding, but also for the traditional aseptic manufacturing processes.