US 6,149,864 A · Supercritical fluid sterilization method

Abstract

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. Agitation, pressure cycling, and the presence of water were found to enhance the sterilization method, which promotes diffusion of the supercritical fluid carbon dioxide into the cells of the microorganism to thereby alter the pH within the cells, killing them. The magnitude and frequency of the pressure cycling, as well as the process time and temperature, may vary according to the type and form of the material to be sterilized and the type of organisms to be killed.

Claims5

Dependent claims

A method for sterilizing polymeric materials for medical applications comprising:

(a) introducing the polymeric material to be sterilized into a reactor, wherein the material potentially includes bacteria to be inactivated;
(b) charging the reactor with an effective amount of carbon dioxide;
(c) pressurizing the reactor to an initial pressure approximately supercritical for the carbon dioxide at a temperature of less than about 60.degree. C.;
(d) cycling the pressure in the reactor by changing the pressure from the initial pressure to one or more higher or lower pressures followed by returning the pressure to or about the initial pressure;
and
(e) maintaining the temperature and pressure at about the initial pressure for a period of time effective to achieve a degree of inactivation of the bacteria if present exceeding 6 log orders.

3 more elements

Dependencies are inferred from the claim text.

Supercritical fluid sterilization method

Life of this patent

Supercritical fluid sterilization method

Life of this patent

Abstract

Claims5