Kinetics of the aeration of ethylene-oxide sterilized plastics.
The aeration of ethylene-oxide (EO) sterilized medical plastic materials is dealth with mathematically, and subsequently the model found is used for calculation of the EO diffusion coefficient in various plastics with the composition and temperature as variables. Absorption and dissolution of EO in various plastic materials are measured at varying concentrations of EO, temperatures and compositions of plastics. The mathematical model is used to evaluate the EO desorption from medical devices under different physico-chemical conditions as well as in vivo. EO analysis methods are evaluated on the basis of the model and are compared with experimental results.
Aeration of medical plastics.
Because the metabolic reaction that gives ethylene oxide is sterilizing qualities also takes place with human protein, it is imperative that any residual gas be removed before the sterilized material is used on the patient. This paper presents a method of estimating aeration time required following sterilization of polyvinyl choride (PVC) to reduced toxic residues to a desired level. The method proposed involves calculation of the coefficient of diffusivity, and the use of a simplified diffusion equation to estimate aeration time.
Sterilization problems of synthetic biocompatible materials.
The past, present, and future of biocompatible materials are reviewed as they relate to cardiovascular prostheses. Many of these materials are no longer simple systems and do not lend themselves to conventional steam or heat sterilization procedures by virtue of their lability. The object of this paper is to briefly discuss sterilization problems encountered with these labile materials using ionization radiation and gases, in terms of their physico-chemical structures.