Smoother catheter coating
A hydrophilic, polymeric coating for urinary catheters that makes them more durable and smooth has been developed by Lombard Medical Technologies, based in Sheffield, UK.
The coating is produced from two biocompatible materials that are commonly used in drug delivery systems, combined with a water-attracting additive (the company could not reveal the composition of the materials). ‘The additive prevents water from evapor-ating, and keeps the coating from drying out,’ explains Dr Kadem Al-Lamee, Managing Director of Lombard.
Traditional PVC catheters are coated with a polymer solution that often contains antimicrobial agents such as nitrofurazone, silver oxide and silver alloy. These are applied to the catheter via UV curing.
However, Al-Lamee explains that these coatings often have problems with durability and drying out too quickly. Water is drawn out of the coating and into the surrounding mucous membrane, causing the catheter’s surface to become sticky. This can damage body tissue when the instrument is later removed.
Lombard’s coating is applied using a dipping process. ‘Just one dip, then it’s taken out to dry. It’s more cost-effective than curing,’ says Al-Lamee. This 20µm layer can remain wet for months without losing viscosity, he adds.
In terms of lubricity, the coating has also shown a coefficient of friction figure of 0.01-0.02, which is comparable to market leading catheter coatings.
Lombard is currently applying for a CE mark to show compliance with European directives, and aims to have the coating available by 1 July. It is also working on a surface modification technique for catheters that will be available at the end of 2008.