Sterilization of medical devices by ethylene oxide, determination of the dissipation of residues, and use of Green Fluorescent Protein as an indicator of process control.
Ethylene oxide (EO) is used to sterilize Oxygenator and Tubing applied to heart surgery. Residual levels of EO and its derivatives, ethylene chlorohydrin (ECH) and ethylene glycol (EG), may be hazardous to the patients. Therefore, it must be removed by the aeration process. This study aimed to estimate the minimum aeration time for these devices to attain safe limits for use (avoiding excessive aeration time) and to evaluate the Green Fluorescent Protein (GFP) as a biosensor capable of best indicating the distribution and penetration of EO gas throughout the sterilization chamber. Sterilization cycles of 2, 4, and 8 h were monitored by Bacillus atrophaeus ATCC 9372 as a biological indicator (BI) and by the GFP. Residual levels of EO, ECH, and EG were determined by gas chromatography (GC), and the residual dissipation was studied. Safe limits were reached right after the sterilization process for Oxygenator and after 204 h of aeration for Tubing. In the 2 h cycle, the GFP concentration decreased from 4.8 (+/-3.2)% to 7.5 (+/-2.5)%. For the 4 h cycle, the GFP concentration decreased from 17.4 (+/-3.0)% to 21.5 (+/-6.8)%, and in the 8 h cycle, it decreased from 22.5 (+/-3.2)% to 23.9 (+/-3.9)%. This finding showed the potentiality for GFP applications as an EO biosensor.
Dias
Fábio N
FN
Department of Pharmaceutical Technology, School of Pharmaceutical Science, University of São Paulo, São Paulo, SP, Brazil.|Nipro Medical Ltda., São Paulo, SP, Brazil.
Ishii
Marina
M
Department of Pharmaceutical Technology, School of Pharmaceutical Science, University of São Paulo, São Paulo, SP, Brazil.
Nogaroto
Sergio L
SL
Nipro Medical Ltda., São Paulo, SP, Brazil.
Piccini
Bruno
B
Nipro Medical Ltda., São Paulo, SP, Brazil.
Penna
Thereza C V
TCV
Department of Pharmaceutical Technology, School of Pharmaceutical Science, University of São Paulo, São Paulo, SP, Brazil.
D001407:Bacillus / Q000187:drug effects; D015374:Biosensing Techniques; D002849:Chromatography, Gas; D004202:Disinfectants / Q000032:analysis*; D004350:Drug Residues / Q000032:analysis*; D005027:Ethylene Oxide / Q000032:analysis*; D049452:Green Fluorescent Proteins / Q000737:chemistry*; D006813:Humidity; D007202:Indicators and Reagents; D010100:Oxygen / Q000737:chemistry; D013171:Spores, Bacterial / Q000187:drug effects; D013242:Sterilization / Q000379:methods*; D013696:Temperature
D004202:Disinfectants; D007202:Indicators and Reagents; D049452:Green Fluorescent Proteins; D005027:Ethylene Oxide; D010100:Oxygen