Ex Parte Cook et al

Patent Trial and Appeal Board

Mar 3, 2014

10891885 (P.T.A.B. Mar. 3, 2014)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte GUY COOK and MATT TREBELLA
__________

Appeal 2012-002571
Application 10/891,885
Technology Center 1600
__________

Before JEFFREY N. FREDMAN, ERICA A. FRANKLIN, and
SHERIDAN K. SNEDDEN, Administrative Patent Judges.

FRANKLIN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal1 under 35 U.S.C. § 134(a) involving claims to
antimicrobial coatings. The Patent Examiner rejected the claims as obvious.
We have jurisdiction under 35 U.S.C. § 6(b). We affirm.

1 Appellants identify the Real Party in Interest as Bacterin International, Inc.
(App. Br. 2.)
Appeal 2012-002571
Application 10/891,885

2
STATEMENT OF THE CASE
Claims 1-8, 10, 14-27, 29, 33-43, 131-133, and 135-141 are on appeal.
Claims 1 and 140 are representative and read as follows:
1. An antimicrobial coating for inhibiting microbial adhesion
comprising:
a hydrogel layer comprising a three-dimensional hydrophilic polymer
network; and
a bioactive agent comprising at least one substantially water-insoluble
antimicrobial metallic material that is solubilized within the hydrogel
layer so that the water-insoluble antimicrobial metallic material is
uniformly dissolved in the antimicrobial coating and remains
solubilized within the antimicrobial coating once the antimicrobial
coating has dried, wherein the antimicrobial metallic material is
dissolved using nitric acid.

140. An antimicrobial coating comprising:
polyvinyl alcohol; and
silver sulfadiazine, wherein the silver sulfadiazine is dissolved in the
polyvinyl alcohol using nitric acid to provide the antimicrobial
coating with a uniform concentration of silver sulfadiazine between
about 20 grams per liter and about 100 grams per liter of
antimicrobial coating, wherein the antimicrobial coating contains
between about 70 μg/cm2 and about 300 μg/cm2 of silver sulfadiazine
at a thickness between about 5 μm and about 100 μm.

(Emphasis added.)

The Examiner rejected the claims as follows:
• claims 1-7, 16, 17, 19-25, 35, 36, 40, 131-133, and 139-141 under
35 U.S.C. § 103(a) as unpatentable over Hennink,2 Opolski,3 Akiyama,4 and
Nesbitt;5

2 US Patent No. 5,219,325 issued to Wilhelmus E. Hennink et al, Jun. 15,
1993.
Appeal 2012-002571
Application 10/891,885

3
• claims 8, 10, 14, 15, 26, 27, 29, 33, 34, 37-39, and 41-43 under
35 U.S.C. § 103(a) as unpatentable over Hennink, Opolski, Akiyama,
Nesbitt, and Murray;6
• claims 1-7, 16-25, 35, 36, 40, and 131 under 35 U.S.C. § 103(a) as
unpatentable over Wood7 and Nesbitt;
• claims 8, 10, 14, 15, 26, 27, 29, 33, 34, 37-39, and 41-43 under
35 U.S.C. § 103(a) as unpatentable over Wood, Nesbitt, and Murray;
• claim 18 under 35 U.S.C. § 103(a) as unpatentable over Hennink,
Opolski, Akiyama, Nesbitt, and Wood;
• claims 133 and 135-137 under 35 U.S.C. § 103(a) as unpatentable
over Hennink, Opolski, Akiyama, Nesbitt, Ku,8 and Gilbert;9
• claim 138 under 35 U.S.C. § 103(a) as unpatentable over Hennink,
Opolski, Akiyama, Nesbitt, LeVeen,10 Touhsaent,11 and Ku;
• claims 133 and 135-137 under 35 U.S.C. § 103(a) as unpatentable
over Wood, Nesbitt, Ku, and Gilbert.

3 Patent Application Publication No. WO 97/29160 by Margaret P. Opolski,
published Aug. 14, 1997.
4 Hisanori Akiyama et al., Effects of sucrose and silver on Staphylococcus
aureus biofilms, 42 J. ANTIMICROBIAL CHEMOTHERAPY 629-634 (1998).
5 R.U. Nesbitt, Jr. & B.J. Sandmann, Solubility Studies of Silver
Sulfonamides, 67 J. PHARM. SCIS. 1012-1017 (1978).
6 US Patent No. 4,920,158 issued to Douglas G. Murray et al., Apr. 24,
1990.
7 US Patent No. 5,260,066 issued to Louis L. Wood et al., Nov. 9, 1993.
8 US Patent No. 5,981,826 issued to David N. Ku et al., Nov. 9, 1999.
9 Gilbert et al., Polymer Gel Actuators, 170 IEE DIGEST 1-5 (1995).
10 US Patent No. 5,810,755 issued to Harry H. LeVeen et al., Sept. 22, 1998.
11 US Patent No. 6,444,750 B1 issued to Robert E. Touhsaent, Sept. 3, 2002.
Appeal 2012-002571
Application 10/891,885

4
OBVIOUSNESS
I. The Rejections Over Combinations Including Hennink and Nesbitt
A. Claims 1-7, 16, 17, 19-25, 35, 36, 40, 131-133, and 139
The Examiner found that Hennink disclosed an exemplary wound
dressing prepared from a solution of polyvinyl alcohol (PVA) and silver
sulfadiazine (AgSD) and spread, i.e., coated, onto a fabric. (Ans. 5-6.) The
Examiner found that Hennink taught that the coated fabric is composed of a
lower layer hydrogel of a polymer cross-linked under the influence of E.B.-
radiation. (Id. at 6.) The Examiner found that Hennink did not specify
adding nitric acid to the PVA-AgSD solution. (Id.)
The Examiner, however, found that Nesbitt taught that silver
sulfonamides show an increase in solubility with increasing hydrogen ion
concentration and that in the presence of a nitrate buffer, the silver ion is
completely dissociated from the sulfadiazine moiety. (Id.) Additionally, the
Examiner found that Nesbitt taught that the dissociation and solubility of
silver sulfadiazine are involved in providing the most favorable
concentration of the silver ion for anti-infective activity. (Id.)
According to the Examiner, it would have been obvious to a person of
ordinary skill in the art at the time the invention was made to have combined
the teachings of Hennink and Nesbitt and utilized nitric acid in the PVA-
AgSD solution of Hennink. (Id.) The Examiner reasoned that one of
ordinary skill in the art would have been motivated to add nitric acid to
Hennink’s solution to solubilize and dissociate the silver ion from the
sulfadiazine to enhance the anti-infective activity as taught by Nesbitt. (Id.
at 7.)
Appeal 2012-002571
Application 10/891,885

5
Appellants contend that “neither Hennink nor Nesbitt (or any other
reference cited by the Examiner) describes a coating in which AgSD
remains solubilized once the coating has dried,” as required by the claimed
invention. (App. Br. 15.) Appellants submit the Declaration of Dr.
Benjamin Luchsinger12 as evidence that “while nitric acid improves the
aqueous solubility of AgSD, nitric acid alone is unable to maintain the
AgSD in a solubilized state.” (Id. at 13) (quoting Luchsinger Declaration ¶
4). Dr. Luchsinger states, “I have observed such maintained solubilization
of AgSD in PVA only with the combination of water, AgSD, nitric acid and
PVA.” (Luchsinger Decl. ¶ 5.) According to Appellants and Dr.
Luchsinger, “[t]hat the combination of water, AgSD, nitric acid and PVA
results in a polymer in which the AgSD remains solubilized is an unexpected
result.” (App. Br. 13) (quoting Luchsinger Decl. at ¶ 6.)
Although we recognize Dr. Luchsinger’s apparent expertise in the
field of Physical Chemistry (see Luchsinger Decl. ¶ 1), we do not find that
his declaration provides evidence of unexpected results sufficient to
overcome the Examiner’s prima facie case of obviousness. “[W]hen
unexpected results are used as evidence of nonobviousness, the results must
be shown to be unexpected compared with the closest prior art.” In re
Baxter Travenol Labs., 952 F.2d 388, 392 (Fed. Cir. 1991). Hennink is the
closest prior art and it discloses a solution comprising PVA and AgSD. Dr.
Luchsinger’s Declaration and Appellants’ argument, however, are directed
to an unexpected property of the claimed composition compared to an AgSD
solution not comprising PVA. According to Dr. Luchsinger, it is the

12 Declaration of Dr. Benjamin Luchsinger, submitted Sept. 30, 2010.
Appeal 2012-002571
Application 10/891,885

6
“addition of PVA” to a solution comprising AgSD and nitric acid that
“would allow AgSD to remain solubilized with the PVA” once the polymer
is dried. (See Luchsinger Decl. ¶ 6.) Therefore, we do not find that
Appellants have provided evidence of unexpected results compared with the
closest prior art. We also find that the results are not commensurate in scope
with the claims, particularly claim 1, which is drawn to the use of any
hydrogel and any water-insoluble antimicrobial metallic material, while the
Declaration provides data for a single polymer, single antimicrobial material,
and single concentration of these components. See In re Harris, 409 F.3d
1339, 1344 (Fed. Cir. 2005) (Unexpected results must also be
“commensurate in scope with the degree of protection sought by the claimed
subject matter.”).
Accordingly, we affirm the rejections of claims 1-7, 16, 17, 19-25, 35,
36, 40, 131-133, and 139 over combinations including Hennink and Nesbitt.
B. Claims 140 and 141
The Examiner found that Hennink’s solution comprising 1% of AgSD
reads on the amount required by the claims, i.e., 2%. (Ans. 7.) Further, the
Examiner found that the amount of a specific ingredient in a composition is
a result effective parameter that a person of ordinary skill in the art would
routinely optimize. (Id. at 7-8.) According to the Examiner, it would have
been obvious to a person of ordinary skill in the art at the time the invention
was made to have optimized the amount of AgSD to achieve the anti-
infective properties desired. (See id.)
Appellants assert that “[n]either Hennink (as evidenced by Opolski
and Akiyama) nor Nesbitt, either alone or in combination, teach or suggest a
coating with a uniform concentration of AgSD between about 20 grams per
Appeal 2012-002571
Application 10/891,885

7
liter and about 100 grams per liter of coating.” (App. Br. 16.) According to
Appellants, one of ordinary skill in the art would not have “added more”
AgSD during routine optimization because “[a]dding more AgSD to the
preparation described in Hennink would not have increased the amount of
AgSD in solution. Additional AgSD would have further prevented the
AgSD from uniformly dissolving and remaining solubilized.” (Id. at 17.)
Appellants assert, “[t]o hold otherwise would require impermissible
hindsight.” (Id.)
We have considered Appellants’ argument but do not find it
convincing. “[D]iscovery of an optimum value of a result effective variable
in a known process is ordinarily within the skill of the art.” In re Boesch,
617 F.2d 272, 276 (CCPA 1980). “[T]he discovery of an optimum value of
a variable in a known process is normally obvious.” In re Antonie, 559 F.2d
618, 620 (CCPA 1977). Appellants’ assertions do not establish that the
amount of AgSD recited in the claims, along with the necessary amount of
nitric acid to increase the solubility of AgSD added, would require more
than routine optimization in view of the teachings of Hennink and Nesbitt
for the reasons discussed by the Examiner. (See Ans. 8, 29-30.)
Accordingly, we affirm the rejection of claims 140 and 141 over the
combination including Hennink and Nesbitt.
Appeal 2012-002571
Application 10/891,885

8
II. The Rejections Over Combinations Including Wood and Nesbitt
Appellants assert that “[t]he Examiner’s reliance on the combination
of Wood and Nesbitt fails for the same reasons as the combination of
Hennink and Nesbitt.” (App. Br. 19.)
Accordingly, we affirm the rejections over combinations including
Wood and Nesbitt for the same reasons discussed regarding the rejections
over combinations including Hennink and Nesbitt.

SUMMARY
We affirm each of the obviousness rejections.

No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

cdc