Appeal No. 95-4669
Application 08/044,674
“high” water sorption. Examples of soft polymers having “low” water sorption are SR
(silicone rubber(cross linked)), PU (polyurethane rubber), and PVC (poly (vinyl
chloride)). Uses of such polymers include tubes, diaphragms, coatings, implants,
pacemakers, adhesives, and blood bags. An example of a soft polymer having “high”
water sorption is PHEMA (poly (hydroxyethyl methacrylate)). Uses of such polymers
include contact lenses, burn dressings, and coatings. On page 18, Hoffman indicates
that the water sorption of PU (polyurethane) is in the range of 1-5%.
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Independent claim 1 calls for an article comprising a hydrophilic polymer having
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an insoluble silver bulk distributed therein, with the polymer having a water absorption
of 5% or more by weight. Independent claim 2 contains similar limitations.
In rejecting claims 1 and 2, and claims 3-5 that depend from claim 2, as being
3Appellant’s specification expressly states on page 2 that, in the present
application, the term “hydrophilic” means “having a water absorption of 5% or more by
weight.”
4Read in light of the supporting specification, it is clear that the term “insoluble”
as used here does not mean zero solubility, but rather very low solubility such that the
active agent (e.g., silver) leaches out slowly during use. See, for example, page 7 of
the specification (“The silver chloride in the catheter of the invention is leached slowly
because of the very low solubility of the salt. This slow leach rate . . . has the
advantage of providing anti-infective activity of long duration.”).
5Appellant’s specification expressly states on page 2 that, in the present
application, the term “bulk distributed” means “substantially evenly distributed
throughout the polymer.”
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Last modified: November 3, 2007