Ex Parte Benovsky et al

Patent Trial and Appeal Board

Apr 15, 2013

12334124 (P.T.A.B. Apr. 15, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE PATENT TRIAL AND APPEAL BOARD
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Ex parte PETR BENOVSKY, LAMBERTUS THIJS, ARJANNE
OVEREEM, JAKUB CASTULIK, JIE ZHU, PETR BARTOS, and
RADOMIR SKOUMAL
____________

Appeal 2011-007801
Application 12/334,124
Technology Center 1600
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Before DONALD E. ADAMS, ERIC GRIMES, and GEORGIANNA W.
BRADEN, Administrative Patent Judges.

ADAMS, Administrative Patent Judge.

DECISION ON APPEAL
This appeal under 35 U.S.C. § 134 involves claims 1-9 and 14 (App.
Br. 1; Ans. 1). We have jurisdiction under 35 U.S.C. § 6(b).
STATEMENT OF THE CASE
The claims are directed to a process for the purification of
montelukast acid. Claim 1 is representative and is reproduced below:
1. A process for the purification of montelukast acid, which
comprises filtering a toluene solution of montelukast acid
through a polar sorbent.
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Claims 1-9 and 14 stand rejected under 35 U.S.C. § 103(a) as
unpatentable over the combination of Niddam-Hildesheim,1 Liu,2 Suri,3
Williamson,4 and Harwood.5
We affirm.

ISSUE
Does the preponderance of evidence on this record support a
conclusion of obviousness?
FACTUAL FINDINGS (FF)
FF 1. Appellants disclose that “[o]nce the montelukast is formed, it is often
desirable to purify it to, e.g., pharmaceutically acceptable quality” (Spec. 28:
¶ [0055]).
FF 2. Appellants disclose that “it is possible to purify … crude
montelukast acid effectively without a conversion thereof into a salt” by a
“process compris[ing] at least one of the following steps: i) Filtration of the
toluene solution of montelukast acid through a polar sorbent, such as silica

1 Niddam-Hildesheim et al., US 2005/0187243 A1, published August 25,
2005.
2 Liu et al., Determination of montelukast (MK-0476) and its S-enantiomer
in human plasma by stereoselective high-performance liquid
chromatography with column-switching, 15 J. Pharm. Biomed. Anal. 631-
638 (1997).
3 Suri et al., WO 2004/108679 A1, published December 16, 2004.
4 Kenneth L. Williamson, Macroscale AND Microscale ORGANIC
EXPERIMENTS, 157, 171, and 342 (4th ed., Richard Stratton, et al., eds.,
Houghton Mifflin Co., Boston) (2003).
5 Laurence M. Harwood et al., EXPERIMENTAL ORGANIC CHEMISTRY
PRINCIPLES AND PRACTICE, 72-77 (Blackwell Scientific Publications, Oxford)
(1989).
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gel, … and ii) Crystallization from a protic solvent such as ethanol under the
absence of light” (Spec. 28: ¶ [0055]).
FF 3. Appellants disclose that a “crude solid product … may be further
purified by any suitable technique such as through crystallization or by
column chromatography, to obtain the desired degree of purity” (Spec. 14:
¶ [0027]).
FF 4. Niddam-Hildesheim suggests a method comprising preparing a
solution of montelukast acid in an organic solvent, such as toluene;
crystallizing montelukast acid; and recovering the crystalline form of the
acid by filtration (Niddam-Hildesheim 2-3: ¶ [0033]; see also id. at 2:
¶ [0030], 3: ¶ [0037], and 5: ¶ [0071] (suggesting recovery of a montelukast
acid precipitate by filtration); Ans. 4).
FF 5. Suri suggests the purification of “montelukast … through column
chromatography on silica gel” (Ans. 4; Suri 4: 6-12).
FF 6. Williamson suggests that “[c]olumn chromatography is one of the
most useful methods for the separation and purification of both solids and
liquids,” wherein “[t]he most common adsorbents [are] … silica gel and
alumina” (Williamson 171: 1-2 and 8-10; see generally Ans. 5).
FF 7. Harwood suggests that “[f]iltration of a suspension to remove
insoluble solids is a fundamental technique of preparative chemistry”
(Harwood 72: 3-4; Ans. 5).
FF 8. Liu suggests that montelukast acid is light sensitive (Ans. 4).
ANALYSIS
Based on the combination of Niddam-Hildesheim, Liu, Suri,
Williamson, and Harwood, Examiner concludes that, at the time Appellants’
invention was made, a person of ordinary skill in this art would have found it
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prima facie obvious to “modify … or … combine prior art reference
teachings to achieve - a process for the purification of montelukast acid
which comprises … filtering a toluene solution of monteluskast [sic.
montelukast] through a polar sorbent” (Ans. 7).
Stated differently, each of Niddam-Hildesheim, Suri, Williamson, and
Harwood suggest methods of purifying a substance by filtration,
chromatography, and/or crystallization (FF 4-7). Appellants’ Specification
also relates to purifying a substance by filtration, chromatography, and/or
crystallization (FF 1-3). Williamson suggests that “[c]olumn
chromatography is one of the most useful methods for the separation and
purification of both solids and liquids,” wherein “[t]he most common
adsorbents [include] … silica gel” (FF 6). Niddam-Hildesheim suggests that
montelukast acid is soluble in toluene (FF 4). Suri suggests the purification
of montelukast acid by column chromatography on silica gel (FF 5).
Therefore, we find no error in Examiner’s reasoning that, at the time
Appellants’ claimed invention was made, a person of ordinary skill in this
art would have found it prima facie obvious to purify a solution of
montelukast acid solubilized in toluene by passing the solution through a
polar sorbent, such as silica gel (FF 4-6; see generally Ans. 6-7). For the
foregoing reasons, we are not persuaded by Appellants’ contention that the
combination of prior art relied upon by Examiner fails to suggest
Appellants’ claimed invention (App. Br. 7-9 and Reply Br. 2-5).
In essence, the issue on Appeal distills down to whether the word
“filtering” modifies the process of Appellants’ claim 1 in such a way as to
exclude “chromatography” methods. Notwithstanding Appellants’
contentions to the contrary, we are not persuaded that it does (Cf. App. Br.
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7-9; Reply Br. 7 (“filtration and chromatography are not equivalent
processes”)).6
We are not persuaded by Appellants’ contention that “[f]iltering … is
not a purification technique” (Reply Br. 6; Cf. FF 2 (“it is possible to purify
… crude montelukast acid effectively … [by a] process compris[ing] … i)
Filtration”) (emphasis added); see also Appellants’ claim 1 (“A process for
the purification of montelukast acid, which comprises filtering”) (emphasis
added)). Further, notwithstanding Appellants’ contention to the contrary,
the evidence of record supports a conclusion that “[c]olumn chromatography
is one of the most useful methods for the separation and purification of both
solids and liquids (FF 6 (emphasis added); Cf. Reply Br. 6 (“column
chromatography separates and/or purifies compounds within a liquid phase
solution”)).
Therefore, notwithstanding Appellants’ contentions to the contrary,
the evidence of record supports a conclusion that montelukast acid can be
purified by passing a toluene solution of montelukast acid over silica gel,
regardless of whether one calls this passing process filtering or
chromatography (Cf. Reply Br. 7). Appellants fail to provide persuasive
evidence or reasoning to support a different conclusion. Specifically,
Appellants fail to establish that, notwithstanding the word “filtering” versus
“chromatography”, their process requires any difference in manipulative
steps or results in a different product, i.e. purified montelukast acid, than
would have been expected by the process suggested by the prior art.

6 We recognize Appellants’ contention that the Examiner’s Answer
introduces new evidence into the record and grant Appellants’ request that
this new evidence be set aside for the purposes of this Appeal (see Reply Br.
6).
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CONCLUSION OF LAW
The preponderance of evidence on this record supports a conclusion
of obviousness. The rejection of claim 1 under 35 U.S.C. § 103(a) as
unpatentable over the combination of Niddam-Hildesheim, Liu, Suri,
Williamson, and Harwood is affirmed. Claims 2-9 and 14 are not separately
argued and fall with claim 1.

TIME PERIOD FOR RESPONSE
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

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