Ex Parte Thassu

Board of Patent Appeals and Interferences

Jun 5, 2008

10223291 (B.P.A.I. Jun. 5, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
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BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
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Ex parte DEEPAK K. THASSU,
Appellant
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Appeal 2008-3530
Application 10/223,2911
Technology Center 1600
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Decided: June 5, 2008
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Before ADRIENE LEPIANE HANLON, CAROL A. SPIEGEL, and
RICHARD M. LEBOVITZ, Administrative Patent Judges.

SPIEGEL, Administrative Patent Judge.

DECISION ON APPEAL

1 Application 10/223,291 ("the 291 application") was filed 19 August 2002.
The real party in interest is said to be L. Perrigo Company (Appeal Brief,
filed 18 September 2007 ("App. Br."), 2.
Appeal 2008-3530
Application 10/223,291

I. Statement of the Case
This is an appeal under 35 U.S.C. § 134 (2002) from a final rejection
of claims 1-6 and 10. Claims 7-9 and 11-33, the only other pending claims,
are withdrawn from consideration (App. Br. 2; Ans.2 2). We have
jurisdiction under 35 U.S.C. § 6(b) (2002). We REVERSE.
The dissolution rate of a particulate drug can vary with the particle
size distribution of the active drug particles in a pharmaceutical formulation
(Spec.3 1:12-28). The subject matter on appeal is directed to a method of
obtaining active particles of a single desired particle size range from a raw
source of pharmaceutically active particles which tend to agglomerate (id.).
The claimed method processes the raw source through a first screen supplied
with ultrasonic energy to break up agglomerates and sized to remove
particles that are too large and then through a second screen sized to remove
particles that are too small (Spec. 3:22-4:9). The active drug particles
retained on the second screen are used to make the final pharmaceutical drug
formulation and are said to have a monomodal particle size distribution
(Spec. 4:9-20). Claim 1 is illustrative and reads (App. Br. App'x of Claims
1, emphasis added):
1. A method of obtaining pharmaceutically active particles
having a desired monomodal particle size distribution,
comprising:
positioning a first screen having a selected mesh aperture
size above a second screen having a selected smaller mesh
aperture size;
placing pharmaceutically active particles on said first
screen; and

2 Examiner's Answer mailed 12 December 2007 ("Ans.").
3 Specification of the 291 application ("Spec.").
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Application 10/223,291

propagating ultrasonic energy to said pharmaceutically
active particles on said first screen while said first screen is
located above said second screen, whereby, the ultrasonic
energy causes agglomerates of smaller particles held together
by electrostatic attraction to become de-agglomerated, and
active particles having a true monomodal particle size
distribution are retained on the second screen.

The Examiner relies on the following references4 of record as
evidence of unpatentability:
Pitchford 3,167,259 Jan. 26, 1965
Liversidge 5,145,684 Sep. 8, 1992
Baichwal 5,472,711 Dec. 5, 1995
McCurdy 5,520,932 May 28, 1996
The Examiner has rejected (i) claims 1-6 under 35 U.S.C. § 103(a) as
unpatentable over the combined teachings of McCurdy, Pitchford, and
Liversidge and (ii) claim 10 under 35 U.S.C. § 103(a) as unpatentable over
the combined teachings of McCurdy, Liversidge, and Baichwal (FR5 2 and
8; Ans. 3).
The dispositive issue is whether the Examiner reversibly erred in
failing to find all limitations of the claimed invention in the prior art.
Specifically, the issue is whether the combined teachings of Pitchford,
Liversidge, Baichwal and/or McCurdy disclose or suggest "positioning a
first screen having a selected mesh aperture size above a second screen
having a selected smaller mesh aperture size," as required by all the claims
on appeal.
Findings of fact set forth in this opinion are supported by a
preponderance of the evidence of record.

4 No references to et al. are made in this opinion.
5 Final Rejection mailed 26 March 2007 ("FR").
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II. Discussion
A claimed invention is not patentable if it would have been obvious to
a person having ordinary skill in the art. 35 U.S.C. § 103(a); KSR Int'l Co. v.
Teleflex, Inc., 127 S.Ct. 1727 (2007); Graham v. John Deere Co. of Kansas
City, 383 U.S. 1 (1966). Facts relevant to a determination of obviousness
include (1) scope and content of the prior art, (2) any differences between
the claimed invention and the prior art, (3) the level of ordinary skill in the
art, and (4) relevant objective evidence of obviousness or non-obviousness.
KSR, 127 S.Ct. at 1734; Graham, 383 U.S. at 17. All limitations of the
claimed invention must be taught or suggested by the prior art to establish
prima facie obviousness. See In re Royka, 490 F.2d 981, 985 (CCPA 1974).
McCurdy discloses a method for obtaining "fine-milled" colestipol
hydrochloride ("FMCH") by wet milling colestipol hydrochloride with a
Comitrol 1700 mill configured with a 222084 microcut head, drying the wet
milled drug, and then sizing it with various equipment to yield either a bi-
modal mixture of particle aggregates and primary particles or a uni-modal
mixture of discrete primary particles (McCurdy abstract; 3:15-17 and 27-31;
6:1-7). According to McCurdy, aggregates of FMCH may be broken up
with a mill with an impact mechanism of size reduction, a Bantom
Mikropulverizer using a 0.046 HB screen to produce a new particle size
distribution, or a precise incremental cutting machine, such as the Comitrol
1700 (id. at 6:43-46; 8:38-48).
The Examiner acknowledges that McCurdy does not disclose first and
second screens (Ans. 6). Hence, McCurdy fails to disclose or suggest
"positioning a first screen having a selected mesh aperture size above a
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second screen having a selected smaller mesh aperture size" as required by
the claimed method.
Pitchford discloses an apparatus for grinding materials to a selective
and uniform particle size (Pitchford 1:9-13; 2:21-24). The apparatus
comprises (i) a grinding/blending chamber for receiving the material to be
processed, (ii) spaced particle separating means, such as screens arranged at
opposite ends or sides of the chamber, designed to permit passage of
particles of a predetermined size, and (iii) a collecting means for receiving
particles passing through the particle separating means (id. at 2:37-47). A
fluid, preferably air, for carrying particles to and away from the spaced
separating means is alternatively pulsed through the chamber through one
screen and out the other (id. at 2:47-51). "In the pulsing cycle, air goes in
through the screen at one end of the chamber, cleaning this screen on the
way in; continues through the chamber and blasts the powder against the
screen at the opposite end of the chamber; finally passing onto a collector"
(id. at 2:51-55). The second pulse in the cycle reverses the air flow,
"thereby blasting powder against the previously cleaned screen while
cleaning the screen against which powder was blasted by the previous pulse"
(id. at 2:60-3:1).
The Examiner does not point out, and we do not find, where Pitchford
discloses or suggests "positioning a first screen having a selected mesh
aperture size above a second screen having a selected smaller mesh aperture
size" as required by the claimed method. The Examiner contends that
Pitchford suggests the claim limitation at issue because "Pitchford teaches
that his screens are adapted to permit the passage of particles of a
predetermined particle size" (Ans. 12). However, as pointed out by the
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Appellant (App. Br. 8), the Pitchford apparatus is using screens of the same
size by virtue of their alternating use in separating particles of the
predetermined size.
Liversidge discloses preparing nanosized drug particles that do not
appreciably flocculate or agglomerate by wet milling in the presence of
grinding media in conjunction with a surface modifier (Liversidge 3:16-24).
Useful surface modifiers include those which physically adhere to, but not
chemically bond to, the surface of the drug particles (id. at 4:30-33). The
surface modifiers are believed to sterically hinder or electrostatically repel
flocculation and/or agglomeration of the drug particles (id., 8:21-29).
Compatible pairs of drug particles and surface modifiers can be selected by
(a) dispersing coarse particles of a selected drug in a liquid in which the drug
is insoluble, (b) wet milling the dispersion, (c) dividing milled material into
aliquots, (d) adding surface modifiers in different amounts to each of the
aliquots, (e) sonicating to disperse agglomerates, and (f) analyzing to
identify those surface modifiers and amounts that provide a stable dispersion
(id. at 7:21-46). In some embodiments, Liversidge discloses using a single
screen to separate a slurry of drug particles and liquid medium from glass
grinding media (id. see e.g., 9:47-51 and 10:56-59).
The Examiner does not point out, and we do not find, where
Liversidge discloses or suggests "positioning a first screen having a selected
mesh aperture size above a second screen having a selected smaller mesh
aperture size" as required by the claimed method.
Baichwal discloses a method of preparing a pharmaceutical
formulation providing a multiphasic release of a therapeutically active drug
when the formulation is exposed to aqueous or gastric fluid (Baichwal 4:40-
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57). Baichwal does not disclose or suggest "positioning a first screen having
a selected mesh aperture size above a second screen having a selected
smaller mesh aperture size" as required by the claimed method. Indeed, the
Examiner relied on Baichwal solely for its disclosure of acetaminophen as a
therapeutically, i.e., pharmaceutically, active drug (Ans. 17-18).
Since neither McCurdy, Pitchford, Liversidge, nor Baichwal disclose
or suggest "positioning a first screen having a selected mesh aperture size
above a second screen having a selected smaller mesh aperture size" as
required by the claimed method, the Examiner has failed to establish a
sufficient factual basis to support a conclusion of prima facie obviousness.
Consequently, we reverse the rejections of (i) claims 1-6 under § 103(a) as
unpatentable over McCurdy, Pitchford, and Liversidge and (ii) claim 10
under § 103(a) as unpatentable over McCurdy, Liversidge, and Baichwal.
It is not necessary to reach other arguments that the applied prior art
also fails to teach or suggest other limitations recited in claim 1.
III. Order
Upon consideration of the record, and for the reasons given, it is
ORDERED that the Examiner's decision to reject claims 1-6 under 35
U.S.C. § 103(a) as unpatentable over the combined teachings of McCurdy,
Pitchford, and Liversidge is REVERSED, and
FURTHER ORDERED that the Examiner's decision to reject claim 10
under 35 U.S.C. § 103(a) as unpatentable over the combined teachings of
McCurdy, Liversidge, and Baichwal is REVERSED.
REVERSED
qsg

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PRICE HENEVELD COOPER DEWITT & LITTON, LLP
695 Kenmoor, S.E.
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