Radiation sterilization compatibility of medical packaging materials

Abstract

We have examined gamma sterilization compatibility for many of medical packaging materials. Techniques used include thermal analysis, physical testing, optical property evaluations, and failure analysis. For a variety of PVC formulations, gamma radiation often leads to discoloration. This results from conjugated poly‐ene sequences formed through dehydrohalogenation degradation during ionizing radiation. In addition to unacceptable color formation, excessive pH shifts and high extractables are often observed. For most polylefins, radiations was found to deplete the antioxidant package and lead to discoloration and/or mechanical failures. For polypropylenes, the degradation can lead to the well‐publicized catastrophic failures during post radiation shelf life storage. These examples and methods to ensure radiation compatibility and shelf‐life stability are presented.

Analytical Methods

“…• rapid determination of di-2-ethylhexyl phthalate, 332 • quantification of plasticizers 351 • leaching of plasticizers from dialyzers, 333,334 • migration of plasticizer to saliva from PVC products chewed by volunteers, 335 • anionic species formed during PVC degradation analyzed with use of ionic conductivity detector, 336 • stabilizer concentration in PVC, 337 • phenol concentration in PVC, 338 • reverse-phase HPLC use for determination of plasticizer hydrophobicity. 339 Gel permeation chromatography, GPC, is used to determine molecular weight and its distribution.…”

“…339 Gel permeation chromatography, GPC, is used to determine molecular weight and its distribution. [336][337][338][339][340][341][342][343][344][345][346] Electric cables used for a long time were analyzed for molecular weight distribution and its change. [336][337][338][339][340][341][342][343][344][345][346] Electric cables used for a long time were analyzed for molecular weight distribution and its change.…”

Principles of Stabilization

“…[308][309][310] Studies of Irganox 1076 and 1011 show that 30-40% antioxidant becomes inactive when a dose of 10 kGy is applied; when the dose was increased to 50 kGy, the loss of antioxidant increased to 61-66%. The major use is polymerization, but also some formulations used in medical applications may contain antioxidants.…”

“…The major use is polymerization, but also some formulations used in medical applications may contain antioxidants. 309 Oxidation of the PVC resin is believed to be a significant cause of compound darkening during exposure to γ-radiation. 308 The increase in yellowness index was related to the polyene formation in PVC and quinone and hydroquinone formation from phenolic antioxidants due to radiation and thermal exposures.…”