Ex parte Walder

Board of Patent Appeals and Interferences

Aug 13, 1998

08044674 (B.P.A.I. Aug. 13, 1998)

Application for patent filed April 9, 1993.1
1
THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered today (1) was not written for
publication in a law journal and (2) is not binding precedent of the Board.
Paper No. 17
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte ANTHONY J. WALDER
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Appeal No. 95-4669
Application 08/044,6741
___________
ON BRIEF
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Before ABRAMS, JOHN D. SMITH, and STAAB, Administrative Patent Judges.
STAAB, Administrative Patent Judge.
DECISION ON APPEAL
Anthony J. Walder appeals from the final rejection of claims 1-6. Claims 7-10,
the only other claims pending in the application, stand withdrawn from consideration
pursuant to 37 CFR § 1.142(b).
The subject matter on appeal relates to an anti-infective medical article designed
Appeal No. 95-4669
Application 08/044,674
2
to inhibit or reduce bacterial growth during its use in a living body. Claim 1 is
illustrative and reads as follows:
1. An anti-infective medical article comprising a hydrophilic polymer having
an insoluble silver salt bulk distributed therein, said polymer having a water absorption
of 5% or more by weight.
The references of record relied upon by the examiner as evidence of
obviousness are:
Pratt et al. (Pratt) 4,849,223 Jul. 18, 1989
Laurin et al. (Laurin) PCT/US83/01404 Sep. 15, 1983
Allan S. Hoffman, Synthetic Polymeric Biomaterials, in Polymeric Materials and Artificial
Organs, 13-29 (Charles G. Gebelein, ed., 1983).
The claims on appeal stand rejected under 35 U.S.C. § 103 as follows:
(a) claims 1-5 as being unpatentable over Laurin in view of Hoffman; and
(b) claim 6 as being unpatentable over Laurin in view of Hoffman and further in
view of Pratt.
Reference is made to appellant’s brief (Paper No. 13) and to the examiner’s
answer (Paper No. 14) for the respective positions of appellant and the examiner with
regard to the merits of these rejections.
Laurin, the examiner’s primary reference, pertains to “compositions useful in
making medical devices and useful in providing antimicrobial coatings on medical
devices” (page 1). As explained on page 3, Laurin’s coating
is prepared by mixing a suitable resin and a compound of a physiological,
Appeal No. 95-4669
Application 08/044,674
In the answer, the examiner refers to Hoffman as Gebelein or Gebelein2
(Hoffman).
3
antimicrobial metal in an appropriate solvent for the resin. . . . The
coating can be applied to a medical device by dipping in the mixture of
resin, solvent and physiological, antimicrobial metal compound and
thereafter allowing the solvent to evaporate. . . . Alternatively, the
medical articles may be sprayed with the mixture and the solvent allowed
to evaporate.
In addition, Laurin states that “a quantity of physiological, antimicrobial metal
compound may be mixed with a resin for direct molding of an article” (page 4).
On page 4, the Laurin reference lists a number of suitable resins and
physiological, antimicrobial metal compounds usable in formulating the mixture. The
listed resins include polyurethane, which is one of the polymers indicated by appellant
as being suitable for use in the present invention, and the listed metal compounds
include silver chloride, which is the silver salt preferred by appellant in making his anti-
infective medical article. Laurin is silent as to the water absorption properties of the
resin used in making the coating.
Hoffman, the examiner’s secondary reference, pertains to applications of2
synthetic polymers in medicine. Hoffman states that “[w]ater sorption in biomaterials is
very important to the functioning of some polymers, such as hydrogels in soft contact
lenses” (page 15). On page 17, Hoffman lists the properties of several solid polymers,
including soft (rubbery) polymers. Such soft polymers may have “low” water sorption or
Appeal No. 95-4669
Application 08/044,674
Appellant’s specification expressly states on page 2 that, in the present3
application, the term “hydrophilic” means “having a water absorption of 5% or more by
weight.”
Read in light of the supporting specification, it is clear that the term “insoluble”4
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.”).
Appellant’s specification expressly states on page 2 that, in the present5
application, the term “bulk distributed” means “substantially evenly distributed
throughout the polymer.”
4
“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%.
Independent claim 1 calls for an article comprising a hydrophilic polymer having3
an insoluble silver bulk distributed therein, with the polymer having a water absorption4 5
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
Appeal No. 95-4669
Application 08/044,674
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unpatentable over Laurin in view of Hoffman, the examiner has taken the following
positions:
Laurin et al disclose an anti-infective medical article comprising a
hydrophilic polymer which includes an insoluble silver salt bulk. . . .
While Laurin et al do not specifically state that the polymers are
hydrophilic, such a property is inherent in most of the polymers disclosed.
For example, it is well known that polyurethane may be hydrophilic.
Laurin et al do not disclose a polymer with a water absorption of 5% or
more.
Gebelein (Hoffman) teaches several polymers which are
hydrophilic with a water absorption of 5% in the area of biomaterials
where water absorption is critical. (See pages 15-18).
It would have been obvious to one having ordinary skill in the art at
the time the invention was made to include the polymers with low water
absorption (1-5%) disclosed in Gebelein (Hoffman) in the invention
disclosed in Laurin et al in order to select a polymer that has a water
absorption of 5% or a low water uptake.
We will not sustain this rejection. From our perspective, what is missing from the
examiner’s evidentiary basis is any teaching of the desirability, and thus the
obviousness, of using a resin in Laurin that has a relatively high water absorption, i.e.,
in the range of 5% or more by weight, as now expressly set forth in claims 1 and 2.
Notwithstanding the examiner’s theory that some sort of disclosure of significant water
absorption for Laurin’s resins may be attributed to the primary reference because (1)
Laurin merely does not “specifically state” that the polymers are hydrophilic, (2)
polyurethane, one of Laurin’s resins, may be hydrophilic, and/or (3) hydrophilicity is, in
the examiner’s opinion, an inherent property in most of the polymers disclosed in
Appeal No. 95-4669
Application 08/044,674
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Laurin, it is our view that the only reasonable conclusion to be drawn from Laurin’s
silence on the matter of water absorption for the resins used therein is that water
absorption is simply of no concern to Laurin. Nothing in Hoffman, and in particular
Hoffman’s statement that water sorption is important in the functioning of some
polymers, such as those used in soft contact lenses, overcomes this fundamental
deficiency in the disclosure of Laurin. While we acknowledge that Hoffman teaches
that the water sorption of polymers used as biomaterials may vary, and for some uses
is a very important consideration, there is nothing in Laurin and Hoffman, taken either
individually or collectively, that would have suggested to the artisan that relatively high
water sorption like that called for in claims 1 and 2 is important for Laurin’s purposes.
In this regard, we do not agree with the examiner that Hoffman teaches or suggests
that water absorption of 5% is critical in the field of biomaterials.
Therefore, we shall not sustain the standing 35 U.S.C. § 103 rejection of claims
1 and 2, nor claims 3-5 which depend from claim 2.
We also shall not sustain the standing 35 U.S.C. § 103 rejection of claim 6 as
being unpatentable over Laurin in view of Hoffman and further in view of Pratt.
Although claim 6 does not expressly call for the water absorption of the second,
hydrophilic polyurethane to be 5% or more by weight, the ordinarily skilled artisan
would understand this to be the case in light of the requirement of claim 6 that the
second polyurethane is “hydrophilic,” and the definition of that term as set forth on page
Appeal No. 95-4669
Application 08/044,674
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2, lines 21-22 of appellant’s specification. The Pratt reference additionally cited
against claim 6 does not overcome the deficiencies of Laurin and Hoffman in this
regard. In fact, Pratt’s teaching at column 3, lines 61-66 that “the polymer . . . may be
substantially hydrophobic in nature. . . . it is preferred to use polyurethane” (emphasis
added) tends to support appellant’s argument that one of ordinary skill in the art would
consider the polyurethane polymers of Laurin and Pratt to be of negligible or low water
absorption (i.e., hydrophobic).
The decision of the examiner is reversed.
REVERSED
)
NEAL E. ABRAMS )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
JOHN D. SMITH )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
LAWRENCE J. STAAB )
Administrative Patent Judge )
Richard J. Rodrick
Becton, Dickinson and Company
One Bection Drive
Appeal No. 95-4669
Application 08/044,674
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Franklin Lake, NJ 07417-1880