Ex Parte Madsen

Board of Patent Appeals and Interferences

Apr 29, 2010

11892919 (B.P.A.I. Apr. 29, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte NIELS JJOERGEN MADSEN
____________

Appeal 2009-014216
Application 11/892,919
Technology Center 1700
____________

Decided: April 29, 2010
____________

Before MICHAEL P.COLAIANNI, LINDA M. GAUDETTE, and
JEFFREY B. ROBERTSON, Administrative Patent Judges.

GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL
Appellant appeals under 35 U.S.C. § 134(a) from the Examiner’s
decision twice rejecting claims 36-56 (Office Action, mailed Jun. 23, 2008,
1), the only claims pending in the application. (Appeal Brief (“App. Br.”),
filed Feb. 11, 2009, 6.) We have jurisdiction under 35 U.S.C. § 6(b).
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We AFFIRM, but denominate our affirmance as a NEW GROUND
OF REJECTION pursuant to 37 CFR § 41.50(b).
The Examiner maintains (Examiner’s Answer (“Ans.”), mailed May
13, 2009, 3-4), and Appellant requests review of (App. Br. 12), the rejection
of claim 36-56 under 35 U.S.C. § 103(a) as unpatentable over Hansen (EP 0
591 091 A1, published Apr. 6, 1994) in view of Johansson (US 4,906,237,
issued Mar. 6, 1990), Rodsten (WO 94/16747, published Aug. 4, 1994) and
Lorenz (US 4,769,013, issued Sep. 6, 1988).
Appellant does not present separate arguments in support of
patentability of any individual claim or sub-grouping of claims. (See
generally, App. Br. 13-22.) Accordingly, we decide the appeal as to all
claims rejected under 35 U.S.C. § 103(a) on the basis of independent claim
36. See 37 C.F.R. § 41.37(c)(1)(vii) (2009).
“Appellant’s invention is directed to coatings [on] medical devices,
such as catheters, and specifically, to coating compositions developed to aid
in the insertion and/or removal of such devices from a patient.” (App. Br. 9
(citing Spec. 1:4-9).) According to Appellant, it was known in the art at the
time of the invention to use hydrophilic polymer coatings on medical
devices. (App. Br. 9.) A “problem with the prior art hydrophilic coatings
was that these coatings were not very durable and easily wore off.” (Id.) By
cross-linking the hydrophilic polymer, it was possible to significantly
increase the durability and useful life of the coating. (Id. (citing Spec. 4:22-
23).) A drawback of cross-linking was that it significantly degraded the
slipperiness of the coating and reduced the drying resistance of the coating.
(App. Br. 9 (citing Spec. 2:10-17 and 3:7-15).) Appellant is said to have
invented a coating comprising a cross-linked hydrophilic polymer which has
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“greatly improved slipperiness and better water retention over the prior art
coatings.” (App. Br. 10.) Claims 36 and 50 are representative of the
claimed invention and are reproduced below from the Claims Appendix to
the Appeal Brief:
36. A hydrophilic coating suitable for use in a medical device
comprising a covalently cross-linked hydrophilic polymer and urea.

50. A method of producing a medical device or instrument suitable for
introduction into a human cavity and said device or instrument having a
hydrophilic coating comprising a covalently cross-linked hydrophilic
polymer and urea, said method comprising the steps of:
a) applying to the medical device or instrument an aqueous solution of
a hydrophilic polymer and urea;
b) evaporating the water present in the aqueous solution of step a);
and
c) cross-linking the hydrophilic polymer of the coating by activation
through radiation and optionally hydrolyzing and optionally
neutralizing the hydrophilic coating.

ISSUES
The dispositive issues presented on appeal are:
1. Did the Examiner err in finding that Hansen’s coating comprises a
covalently cross-linked hydrophilic polymer? and
2. Did the Examiner err in determining that it would have been
obvious to have added urea to Hansen’s coating material as an osmolality-
increasing compound?
We answer these questions in the negative.

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FINDINGS OF FACT (“FF”)
The Appealed Claims
1. Independent claims 36, 43, and 50 broadly recite a coating
comprising “a covalently cross-linked hydrophilic polymer.” The
independent claims do not recite a specific hydrophilic polymer and do not
preclude the presence of a second hydrophilic polymer in the recited coating.
The Specification states that “cross-linking is [preferably] effected through
polymerization of vinylic unsaturated groups” and that “[o]ther preferred
cross-linking may be obtained using . . . polyethylene glycols.” (Spec. 5:1-
6; see also, Example 3 (“A dispersion of polyisocyanate was prepared from
50 parts of a PVP/hydroxyethylmethacrylate-copolymer having 10 mole %
HEMA, 10 parts polyethyleneglycol having Mw 10,000, 30 parts of
polyisocyanate (Bayhudur® VP LS 2032 from Bayer AG) and 10 parts of
sodium chloride in the form of a 10% dispersion in water.”).)
2. According to the Specification, “[c]ross-linking of hydrophilic
coatings according to the invention may be effected by radiation and is
preferably effected by activation using UV light.” (Spec. 5:7-8.) The
independent claims do not require a photo initiator (see Spec. 6:27; claim 50
(reciting “cross-linking . . . by “activation through radiation”).)
3. The independent claims require that the coating comprise urea.
The Specification describes urea as a “water soluble compound” and an
“osmolality-increasing compound.” (See Spec. 5:16-24.) The claims do not
preclude the presence of a second water soluble (or osmolality-increasing)
compound. The Specification states that the inventive coating may contain
a mixture of compounds, including sodium chloride and urea, which are
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soluble or insoluble in the solution into which they are incorporated. (Id.;
see also, original claim 3.)
Hansen
4. Hansen discloses “a coating material comprising a binder (a), a
hydrophilic polymer (b) as well as, if desired, an osmolality-increasing
compound (c).” (Hansen, p. 4, ll. 33-34.) The coating material is in the
form a dispersion having a disperse phase dispersed in a dispersant.
(Hansen, p. 4, ll. 34-35.)
5. Hansen discloses that the binder (a) must be substantially
insoluble in the solvent or mixture of solvents used to form the dispersion.
(Hansen, p. 4, l. 40.) The solvent may be water. (Claim 5.) The binder may
be curable by electron radiation, in which case a photo initiator is not
required. (Hansen, p. 4, ll. 56-57; see also, p. 6, ll. 5-7.) Alternatively, the
binder may be laser beam or UV curable. (Hansen, p. 4, ll. 57-58.)
6. The hydrophilic polymer component (b) may be one or more
hydrophilic polymers which are only slightly soluble in the dispersant, and
one or more hydrophilic polymers which are substantially completely
soluble in the dispersant, e.g., polyvinyl pyrrolidone (PVP). (Hansen, p. 4,
ll. 53-55.) According to Hansen, “the use of sparingly soluble hydrophilic
polymers renders it possible for this polymer or a portion thereof to enter the
disperse phase of the coating material. As a result, a portion of the
hydrophilic polymer ingredient can be intimately mixed with the binder,
whereby an excellent affinity between the binder phase and the hydrophilic
phase can be ensured in the coating, i.e. the portion of the dispersant
remaining after the drying of the coating.” (Hansen, p. 7, ll. 8-12.) Hansen
explicitly identifies a mixture of PVP and PEG (see e.g., p. 7, ll. 31-33),
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noting that PVP functions as the soluble hydrophilic polymer (Hansen, p. 7,
ll. 32-33) and that PEG “is water-soluble, but precipitates like proteins in a
concentrated solution of salt in water” (Hansen, p. 7, ll. 5-8). One of
ordinary skill in the art at the time of Appellant’s invention would have
understood that hydrophilic polymers other than PEG could be used in
forming the above-described intimate mix between the binder and
hydrophilic polymer ingredient. (See Hansen, p. 7, ll. 5-6.)
7. Hansen’s osmolality-increasing compounds are described as
“water-soluble compounds” and include “sodium chloride,” “glucose,” and
“all said osmolality-increasing compounds being mentioned in . . . US[]
4,906,237 (Johansson et al.).” (Hansen, p. 8, ll. 22-28.) Hansen notes that
the osmolality-increasing compound “can have an essential effect on the
structure of the coating material. (Hansen, p. 7, ll. 30-31.) One of ordinary
skill in the art at the time of Appellant’s invention would have understood
that more than one osmolality-increasing compound could be used in
Hansen’s coating to achieve various effects on the coating structure,
depending on the chosen solvents, binder and hydrophilic compounds.
Johansson
8. Johansson discloses a method of forming an improved
hydrophilic coating on a polymer surface (Title), such as the surface of a
biomedical device (col. 1, l. 21). The polymer surface is a hydrophilic
polymer layer, such as PVP, which is made non-reactive by curing.
(Johansson, col. 2, ll. 41-43.) Johansson’s method involves applying to the
polymer surface a coating of an osmolality increasing compound, optionally
mixed with a polymer, dissolved in water or a lower alcohol. (Johansson,
col. 2, ll. 15-21.) The optional polymer should be compatible with the
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polymer in the hydrophilic polymer layer. (Johansson, col. 2, ll. 21-23.)
Johansson teaches that “[d]ifferent types of osmolality increasing
compounds can be used,” including “glucose, sorbitol, sodium chloride,”
and other non-toxic compounds. (Johansson, col. 2, ll. 6-14.)
Rodsten
9. Rodsten discloses a method for producing a hydrophilic coating
on a surface of a medical device. (Rodsten, title.) Rodsten discloses the use
of an osmolality increasing compound which may be soluble or insoluble in
the solution in which it is incorporated. (Rodsten, p. 3, ll. 8-17.) Rodsten
discloses the use of nontoxic organic or inorganic salts as the osmolality
increasing compound, but expresses a preference for urea. (See Rodsten, p.
3, ll. 15-23.) Rodsten teaches that urea provides improved water retention in
PVP coatings. (See Rodsten, claims 5 and 8.)
PRINCIPLES OF LAW
Where the Examiner establishes a reasonable assertion of inherency
and thereby evinces that a claimed process appears to be identical to a
process disclosed by the prior art and/or that the products claimed by the
applicant and disclosed in the prior art appear to be the same, the burden is
properly shifted to the applicant to show that they are not. See In re Spada,
911 F.2d 705, 708 (Fed. Cir. 1990); In re Best, 562 F.2d 1252, 1254-56
(CCPA 1977).
“A reference may be said to teach away when a person of ordinary
skill, upon reading the reference, would be discouraged from following the
path set out in the reference, or would be led in a direction divergent from
the path that was taken by the applicant.” In re Gurley 27 F.3d 551, 553
(Fed. Cir. 1994).
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ANALYSIS
Appellant contends the Examiner erred in finding that Hansen’s
coating comprises a covalently cross-linked hydrophilic polymer. (App. Br.
14.) In support of this contention, Appellant argues that in Hansen’s
method, “the hydrophilic polymer (PVP) and an osmolality agent (NaCl) are
dissolved” whereas “the prepolymer binder and photoinitiator . . . are present
in the aqueous solution (dispersant) as large droplets . . . in suspension.”
(App. Br. 15.) According to Appellant, because the photo initiator is only in
direct contact with the binder, cross-linking only occurs in the binder and not
in the hydrophilic polymer. (App. Br. 16.)
Appellant’s argument is not persuasive for the following reasons:
Hansen explicitly discloses using two types of hydrophilic polymers, one of
which “can be intimately mixed with the binder, whereby an excellent
affinity between the binder phase and the hydrophilic phase can be ensured
in the coating.” (See FF 6.) Hansen teaches that the binder may be cross-
linked without the presence of a photo initiator, e.g., using electron
radiation. (FF 5.) Appellant’s Specification indicates that covalent cross-
linking of hydrophilic polymers, including PEG, may be effected using
radiation of a type which does not require a photoinitiator. (FF 2.) Thus, it
is reasonable to conclude that where Hansen uses a hydrophilic polymer of
the type which is not completely soluble in the solvent, e.g., PEG, some
mixing of the hydrophilic polymer and binder will occur such that both will
be cross-linked.
Appellant also contends the Examiner erred in determining that it
would have been obvious to have added urea to Hansen’s coating material as
an osmolality-increasing compound. Appellant argues that “Johansson
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teaches [] the inorganic salt, NaCl, is superior to an organic salt, such as
urea, for increasing the slipperiness of the hydrophilic coating.” (App. Br.
17.) Appellant thus contends Johansson teaches away from using urea in
Hansen’s coating. (Id.)
Appellant has not persuaded us that one of ordinary skill in the art
would have been discouraged from using urea in Hansen’s coating for the
following reasons:
Hansen uses NaCl as the osmolality-increasing compound in a
preferred embodiment in which a coating contains a hydrophobic compound
and two hydrophilic compounds (PVP and PEG). Hansen’s reasons for
using NaCl include its effect on PEG, i.e. NaCl causes PEG to precipitate,
allowing intimate mixing with the binder. (FF 6.) As discussed above,
when the binder is cross-linked by radiation, it is reasonable to conclude that
the portion of the PEG which is intimately mixed with the binder would also
be cross-linked. (See supra p. 8.)
Hansen explicitly states that the disclosed coating may contain any of
the osmolality-increasing compounds mentioned in Johansson. (FF 7.)
Johansson broadly discloses the use of non-toxic compounds for increasing
osmolality (FF 8) and Rodsten explicitly discloses the benefits of using the
non-toxic compound urea to provide improved water retention in coatings
containing PVP (FF 9). Therefore, one of ordinary skill in the art would
have been motivated to include urea in Hansen’s coating, in addition to NaCl
to achieve improved water retention of the soluble, non-cross-linked PVP
component of Hansen’s coating. (See FF 7 and FF 3 (appealed claims do not
preclude the presence of a second osmolality-increasing compound).)
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The above-described modification to Hansen’s coating would result in
a prior art coating which is substantially identical to Appellant’s claimed
coating. Therefore, the burden is on Appellants to show a patentable
distinction between the claimed and prior art coatings. Appellant has
submitted evidence of unexpected results in support of his contention that it
would not have been obvious to have substituted urea for NaCl in Hansen’s
coating. (See, e.g., App. Br. 21.) However, Appellant has not provided
evidence which shows a patentable difference between the claimed coating
(see FF 1-3) and Hansen’s modified coating containing PVP, PEG, NaCl,
and urea. (See generally, App. Br. 18-21, Reply Brief (“Rep. Br.”), filed
July 9, 2009, and Evidence Appendix VI & VII (comparative testing is
limited to coatings containing PVP, and NaCl or urea).)
CONCLUSION
In view of the foregoing, Appellant has not persuaded us that a
preponderance of the evidence weighs in favor of nonobviousness.
We recognize that our conclusion is based on facts and reasons which
differ substantially from those advanced by the Examiner. Therefore we
denominate our affirmance of the rejection of claim 36-56 under 35 U.S.C. §
103(a) as unpatentable over Hansen, in view of Johansson, Rodsten, and
Lorenz as a NEW GROUND OF REJECTION. 37 C.F.R. § 41.50(b).

37 C.F.R. § 41.50(b) provides that an appellant, WITHIN TWO
MONTHS FROM THE DATE OF THE DECISION, must exercise one of
the following two options with respect to the new ground of rejection to
avoid termination of the appeal as to the rejected claims:
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(1) Reopen prosecution. Submit an appropriate
amendment of the claims so rejected or new
evidence relating to the claims so rejected, or both,
and have the matter reconsidered by the examiner,
in which event the proceeding will be remanded to
the examiner. . . .
(2) Request rehearing. Request that the
proceeding be reheard under § 41.52 by the Board
upon the same record. . . .

AFFIRMED;
37 C.F.R. § 41.50(b)

PL Initial:
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