Sterilisation

Disclosed are compositions and methods for the biocompatible sterilization of materials, in particular, of medical devices and implants. Sterilization is achieved by deactivation of microorganisms through treatment of the material with a mixture of at least one microbiocidal additive and a high-pressure or supercritical fluid, for example, high-pressure carbon dioxide or supercritical carbon dioxide. This abstract is intended as a scanning tool for purposes of searching in the particular art and is not intended to be limiting of the present invention.

This study reports the effect of exposure to liquid carbon dioxide on the mechanical properties of selected medical polymers. The tensile strengths and moduli of fourteen polymers are reported. Materials were exposed to liquid CO2, or CO2 + trace amounts of aqueous H2O2, at 6.5 MPa and ambient temperature. Carbon dioxide uptake, swelling, and distortion were observed for the more amorphous polymers while polymers with higher crystallinity showed little effect from CO2 exposure.

Sterilization methods and apparatus are effective to achieve a 6-log reduction in CFUs of industry standard bacteria and bacterial spores, i.e., B. stearothermophilus and B. subtilis spores, by subjecting sterilizable materials to a chemical additive-containing carbon dioxide sterilant fluid at or near its supercritical pressure and temperature conditions. Most preferably, the chemical additive-containing supercritical carbon dioxide sterilant fluid is agitated during sterilization, e.g., via mechanical agitation or via pressure cycling.

Gentle alternatives to existing sterilization methods are called for by rapid advances in biomedical technologies. Supercritical fluid technologies have found applications in a wide range of areas and have been explored for use in the inactivation of medical contaminants. In particular, supercritical CO2 is appealing for sterilization due to the ease at which the supercritical state is attained, the non-reactive nature, and the ability to readily penetrate substrates.

Disclosed are processes for sterilization of cyanoacrylate adhesive compositions, the compositions, comprising 2-cyanoacrylate ester monomers, so produced and a method for assaying the effectiveness of the sterilization process. The process comprises heating the adhesive composition to from about 70° C. to about 140° C. for an effective amount of time.

A method is provided for sterilizing materials, particularly polymers, for drug delivery and implantation, wherein the material is treated with supercritical fluid carbon dioxide at pressures in the range of 2000 to 3000 psi (140 to 210 bar) and temperatures preferably between 30 and 45.degree. C. for periods between 20 minutes and six hours, more preferably between 0.5 and 2 hours.

The use of CO2 under pressure (dense CO2) is one of the most promising techniques to achieve cold pasteurization and/or sterilization of liquid and solid ma- terials, and is likely to replace or partially substitute currently and widely applied thermal processes. Although the ability of CO2 to inactivate microorganisms has been known since the 1950s, only within the last 15 years it has received special attention, and the scientific and economic interest towards practical applications is presently growing more and more.

Sterility is required for medical devices use in invasive medical procedures, and for some situations in the food industry. Sterilization of heat- sensitive or porous materials or devices, such as endoscopes, porous implants, liquid foodstuff, and liquid medicine, poses a challenge to current technologies. There has been a steady interest in using high-pressure carbon dioxide as a process medium for new sterilization technology. Among the potential advantages are that CO2 may sterilize at low temperatures.