Moelnlycke Health Care AB v Brightwake Ltd (t/a Advancis Medical)

Patent claims must be construed purposively by asking what the skilled reader would understand the language to mean. The court must not import limitations from the specification where the claim language does not support them.

A product claim is concerned with the product as it exists, irrespective of its manufacturing process. In a multilayer laminate, the carrier material is the material which carries the claimed gel, not an arbitrarily selected subset of layers.

For novelty, prior art must disclose and enable the claimed subject matter. A general disclosure does not anticipate a particular combination. For obviousness, routine trials and familiar choices do not involve invention, but a simple step is not necessarily obvious without hindsight.

The claimant alleged that the defendant’s Episil and Episil Absorbent wound dressings infringed claims 6, 7 and 10 of European patent EP 0 633 757. The defendant denied infringement and challenged validity on novelty and inventive-step grounds, relying principally on European patent application EP 0 251 810 A2 (Brassington) and United States patent 4,921,704 (Fabo).

The products were multilayer laminates. Silicone was applied before perforations were made, and an unperforated polyurethane backing film formed part of the finished dressing. The central issues were the construction of “carrier material”, “silicone gel”, and the permeability requirements in claim 6, followed by infringement, novelty, enablement and obviousness.

1. Construction. The term “silicone gel” meant a silicone material comprising a polymer network suspended in a liquid, intermediate between uncured fluid and fully cross-linked elastomer. Although gels were usually tacky, the claim did not import a requirement of tackiness or any particular adhesion level.
2. Claim 6 was a product claim, not a product-by-process claim. Its permeability requirements could not be assessed by reference to the defendant’s particular manufacturing process. The carrier material was the material in the finished dressing which carried the silicone gel. In a multilayer laminate it was the whole relevant laminate, not a selected subset of layers.
3. The defendant’s products therefore lacked a perforated carrier material within claim 6. Claims 6, 7 and 10 were not infringed.
4. Novelty and enablement. Novelty required both disclosure and enablement. Brassington disclosed a dressing using an apertured plastics film, but did not disclose the required combination of permeability and silicone gel on only one side. Claim 6 was therefore novel. Brassington nevertheless enabled what it disclosed. The skilled team could use familiar coating techniques and routine trial and error without prolonged research.
5. Inventive step. Applying the structured approach in Pozzoli v BDMO [2007] EWCA Civ 588, it was obvious over Brassington to use an apertured plastic film, a tacky silicone gel on the wound side and a non-tacky silicone rubber on the other side, and to cure the silicone before making the perforations. Claims 6 and 7 were consequently obvious. Claim 10 added only an obvious composite plastic-and-fibre carrier intended to improve adhesion.
6. Coating silicone on only one side, without silicone of any kind on the other side, was not itself obvious over Brassington. That finding did not save claim 6 because the obvious tacky-gel/non-tacky-rubber combination fell within its scope. The Fabo prior art did not render claim 6 obvious.
7. Disposition. None of the products infringed claims 6, 7 or 10. Claims 6 to 10 were invalid.