Biocompatibility and health risk assessment of a silver nanoparticle wound dressing

Background

The client wished to market a new anti-bacterial dressing utilising nanoparticles of silver and intended to be worn for up to 30 days. Bibra was asked to assess a) the biocompatibility of the dressing and b) whether or not there would be any significant toxicological risks to patients should any nanoparticles leach out of the dressing and be absorbed.

Client

A leading manufacturer of advanced wound care products.

Project goals

To evaluate the biocompatibility of the dressing and assess whether or not the nanoparticles in question could pose any significant health risk to users if systemically absorbed.

Approach

An assessment of the dressing’s biocompatibility was carried out according to ISO 10993, Council Directive 93/42/EEC and US FDA guidelines utilising extensive data generated by the client.

A toxicological health risk assessment was carried out, in compliance with ISO 10993-17, on the silver nanoparticles. As no leaching was detected in an ISO 10993-18 (chemical characterisation) test, an estimated “worst-case” scenario was assumed where the nanoparticle was able to leach from the dressing at the analytical Limit of Quantification. A comprehensive literature review was carried out and the key hazard points of this particular nanoparticle were summarised and a suitable toxicological point of departure was identified. Health precautionary allowable limits were then calculated for neonates/infants, children, women and men. These limits were then compared against two exposure scenarios, the first being that all elutable nanoparticles were systemically absorbed, the second using Expert Group-proposed values for absorption through abraded skin.

Project outcome

After evaluating the relevant data against the endpoints required by the guidelines mentioned above, it was concluded that the dressing was considered to be biocompatible when applied for its intended use.

In both risk assessment scenarios it was concluded that there was no significant health risk to patients, even if all (hypothetical) leachable nanoparticles were to enter the blood stream.

Bibra project team

Pete Watts

Charlie Johnson

 

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