Cold ionizing radiation sterilization
AssigneeMedtronic, Inc.
InventorsDrew Powell Amery, Matthew F. Myntti
Life of this patent
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Abstract
A hydratable gel-forming polymer may be sterilized by chilling the polymer below ambient temperature and sterilizing the chilled polymer using ionizing radiation (e.g., E-Beam radiation). Doing so may reduce the degradation in physical properties caused by ionizing radiation sterilization of the polymer while at ambient temperature, and may preserve or retain desired hydration or gel-forming characteristics.
Claims34
A method for polymer sterilization, which method comprises:
- a) providing a dry hydratable gel-forming polymer chilled below ambient temperature, the polymer having a weight average molecular weight before sterilization of at least about 7 kDa;
- and
- b) sterilizing the chilled polymer using ionizing radiation while the polymer is chilled below ambient temperature, to provide a sterile hydratable gel-forming polymer whose polydispersity index is greater than that of the polymer if it has not been sterilized, or whose weight average or number average molecular weight is greater than the respective weight average or number average molecular weight of the polymer if sterilized using ionizing radiation while at ambient temperature.
A medical device comprising a sterile dry hydratable gel-forming polymer, which sterile polymer is prepared by a method comprising:
- a) providing a dry hydratable gel-forming polymer chilled below ambient temperature, the polymer having a weight average molecular weight before sterilization of at least about 7 kDa;
- and
- b) sterilizing the chilled polymer using ionizing radiation while the polymer is chilled below ambient temperature, to provide a sterile hydratable gel-forming polymer whose polydispersity index is greater than that of the polymer if it has not been sterilized, or whose weight average or number average molecular weight is greater than the respective weight average or number average molecular weight of the polymer if sterilized using ionizing radiation while at ambient temperature.
A treatment method, which method comprises:
- a) hydrating a gel-forming polymer to form a cohesive hydrogel, and
- b) injecting or spraying a layer of the cohesive hydrogel onto tissue or other body structure
- wherein said polymer is prepared by:
- i) providing a dry hydratable gel-forming polymer chilled below ambient temperature, the polymer having a weight average molecular weight before sterilization of at least about 7 kDa;
- and
- ii) sterilizing the chilled polymer using ionizing radiation while the polymer is chilled below ambient temperature, to provide a sterile hydratable gel-forming polymer whose polydispersity index is greater than that of the polymer if it has not been sterilized, or whose weight average or number average molecular weight is greater than the respective weight average or number average molecular weight of the polymer if sterilized using ionizing radiation while at ambient temperature.
Dependencies are inferred from the claim text.