Physico-chemical and toxico-hygienic aspects of using ethylene oxide for the sterilization of articles for medical use. Part 2. Toxicity and risk of ethylene oxide entering the organism by non-inhalation routes.

Results of investigation of toxicity of ethylene oxide (EO) entering the organism by routes other than inhalation (subcutaneous, intramuscular, intraperitoneal, intravenous) have demonstrated that the substance causes intoxication characterized by polytropic effect on many vitally important organs and systems. The changes in most of the indices under study show a phasic character and dose-time dependence. In both the acute and chronic effect, impairment of the state of the nervous system, the liver, kidney, blood and reactivity of the organism come to the foreground. After one single entrance, EO becomes manifest as a low-risk (class 4) compound (Limac for subcutaneous, intraperitoneal and intravenous routes being 5.0, 0.5 and 1.0 mg/kg, respectively); after repeated exposure as a high-risk (class 2) compound (Limchr for subcutaneous and intraperitoneal route being 1.0 and 0.1 mg/kg, respectively). In comparison with the subcutaneous route, the intravenous and intraperitoneal routes are more dangerous. The obtained parameters of EO toxicometry can be used as a basis for the calculation of safe levels of residual quantities of the compound in articles for medical use.

The parameters of comparative evaluation of insecticidal activity of preparations in aerosol containers.

On the basis of experimental data, the authors present a group of parameters for the purpose of unification of comparative evaluation of the insecticidal effect of preparations in aerosol containers designed for combatting flying and non-flying domestic insects. The advisability of evaluation of the effect of the preparations for combatting flying insects according to the concentration of insecticides ensuring death of flies in the course of 15 min and the corresponding expenditure of the mixture has been substantiated. Preparations designed for combatting non-flying insects should be evaluated according to the coefficients of acute action, ovicidal and residual effects. To facilitate analysis and evaluation of the preparations in aerosol containers, the authors propose their classification according to the parameters of the insecticidal effect. Classification of the preparations under study according to their parameters is presented. It has been demonstrated that compositions containing pyrethroids and their mixtures with DDVP--Neofos, Neofos-2 and Pif-Paf are the most efficient.

Physico-chemical and toxicologo-hygienic aspects of using ethylene oxide for the sterilization of medical appliances. Part I. Sorption and diffusion of ethylene oxide in polymeric materials.

Sorption ability of polymeric materials for medical purposes was studied with respect to the sterilizing gas - ethylene oxide - at 23, 35 and 55 degrees C. Sorption coefficients of ethylene oxide (EO) for the materials under study were calculated on the basis of results. Investigation of the kinetics of desorption of EO from the polymeric materials for medical purposes has shown that its content changes exponentially depending on the time of degassing. However, the lines in the 1g Q/Q0 - tau coordinates show a sharp break which testifies to a change in the mechanism of the process determining the character of the mentioned dependence. In the first region, corresponding to high concentrations and short periods of time, the determining process is diffusion while in the second region (low concentrations, long time intervals) - it is desorption of EO molecules most firmly bound to the polymer. Diffusion coefficients were calculated for the first region. The possibility of predicting the time periods of removing ethylene oxide from the polymeric materials was demonstrated for both stages on the basis of calculated diffusion coefficients and kinetic curves of degassing. Recommendations were given for the use of polymers for medical appliances and apparatuses.

Insecticidal properties of permethrin and permethrin-based agents.

A study of some insecticidal properties of a new pyrethroid, permethrin, showed that it was a highly effective insecticide at contact, superior in this respect to neopinamin for German cockroaches, houseflies and bedbugs and superior to sumithrin for German cockroaches. Combinations of permethrin with neopinamin displayed synergism. The most active combination contained permethrin and neopinamin in a ratio of 9:1. This combination surpassed in insecticidal activity the most effective combination of sumithrin with neopinamin.