Health risk assessment of extractables – a metallocene polyethylene sheath


A medical devices manufacturer.


The company had commissioned extractables and headspace analyses on a metallocene polyethylene sheath that may be in transient contact with internal tissues during implantation surgery. A number of organic and inorganic substances were detected in the analysis.

Project goals

Bibra toxicologists were asked to assess the possible health impact if the calculated exposures were seen in practice.


Bibra estimated “worst-case” exposures that might result from use of the device, and assessed whether these hypothetical exposures might pose any significant health risk to patients – assuming that the extractables might represent genuine leachables. It was assumed that exposure approximated to a single acute dose on the day of implantation. The various detected compounds were grouped into generic chemical classes, where possible, and assessed as combined exposures. Appropriate toxicity data were used in the assessment, focusing on the injection routes (and using inhalation and oral toxicity data where necessary).

Project outcome

Bibra was able to provide the client with a health risk assessment report, clearly showing that that the organic and inorganic extractables, and headspace volatiles, would not pose any significant health risks to patients exposed via leaching, at the estimated exposure levels, from the sheath.

Project Team

Daniel Threlfall

James Hopkins


Extractables and Leachables

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