       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

       APTALIS PHARMATECH, INC., IVAX
           INTERNATIONAL GMBH,
               Plaintiffs-Appellees

                           v.

           APOTEX INC., APOTEX CORP.,
               Defendants-Appellants
              ______________________

                      2017-1344
                ______________________

    Appeal from the United States District Court for the
District of Delaware in No. 1:14-cv-01038-SLR-SRF,
Judge Sue L. Robinson.
                ______________________

               Decided: January 4, 2018
                ______________________

   JOHN R. LANE, Fish & Richardson, PC, Houston, TX,
argued for plaintiffs-appellees. Also represented by
SUSAN E. MORRISON, Wilmington, DE; JONATHAN ELLIOT
SINGER, San Diego, CA.

   WILLIAM R. ZIMMERMAN, Knobbe, Martens, Olson &
Bear, LLP, Washington, DC, argued for defendants-
appellants. Also represented by THOMAS P. KRZEMINSKI;
KAREN MARIE CASSIDY, CRAIG S. SUMMERS, Irvine, CA.
2                   APTALIS PHARMATECH, INC.   v. APOTEX INC.



                 ______________________

     Before REYNA, WALLACH, and STOLL, Circuit Judges.
STOLL, Circuit Judge.
    In this Hatch-Waxman case, Apotex Inc. and Apotex
Corp. appeal from the district court’s claim construction of
“extended release coating” and its finding that Apotex’s
product infringes U.S. Patent Nos. 7,790,199 and
7,829,121. We conclude that the district court erred by
not construing the term “extended release coating” to
require a continuous outer film, as taught by the intrinsic
evidence. Accordingly, we vacate the infringement find-
ing and remand for further proceedings.
                             I.
    The goal of a drug delivery system is to achieve rapid-
ly a therapeutically effective concentration of drug in the
body and to maintain that concentration throughout the
treatment period. When a patient swallows a tablet,
gastrointestinal fluids dissolve the drug inside the tablet,
and the drug is absorbed into the body. In an immediate
release formulation, the majority of the drug dissolves
within an hour because the tablet disintegrates once it is
swallowed, and the body’s gastrointestinal fluids contact
and dissolve the drug. Therefore, patients seeking con-
tinuous relief from their symptoms must take an immedi-
ate release formulation several times per day.
    An extended release formulation, as its name implies,
can sustain therapeutically effective drug concentrations
over a prolonged period by releasing the drug at a slower
rate. These formulations employ controlled release mate-
rials that surround the drug and create a barrier through
which gastrointestinal fluids must travel to access the
drug, or “active” substance. The controlled release mate-
rial decreases the rate at which gastrointestinal fluids
penetrate the tablet to dissolve the drug and the rate at
APTALIS PHARMATECH, INC.   v. APOTEX INC.                 3



which the dissolved drug escapes the tablet to be absorbed
into the body.
    Aptalis Pharmatech, Inc. and Ivax International
GmbH own the ’199 and ’121 patents (collectively, the
“asserted patents”), which relate generally to extended
release dosage forms of cyclobenzaprine hydrochloride, a
skeletal muscle relaxant. 1 Instead of requiring three
daily doses of cyclobenzaprine, as in the prior art, the
asserted patents disclose an extended release cycloben-
zaprine formulation that provides twenty-four hour relief
from muscle spasms with a single dose.
    The asserted patents teach two different formulations
that use a water insoluble polymer coating to achieve an
extended release profile. The parties refer to these alter-
natives as membrane systems and matrix systems. In a
membrane system, a water insoluble polymer coating is
applied onto an active-containing core:
    The active core of the dosage form of the present
    invention may comprise an inert particle such as
    a sugar sphere, or an acidic or alkaline buffer
    crystal, which is coated with a skeletal muscle re-
    laxant such as cyclobenzaprine . . . . The drug
    layered beads may be coated with a protective
    seal coating of OPADRY® Clear to produce IR
    [immediate release] Beads. . . .
        ER [extended release] Beads can be produced
    by applying a functional membrane comprising a
    water insoluble polymer alone or in combination
    with a water soluble polymer onto IR Beads.




   1    The asserted patents share a common specifica-
tion, and unless otherwise noted, all citations are to the
’199 patent.
4                     APTALIS PHARMATECH, INC.   v. APOTEX INC.



’199 patent col. 3 l. 67 – col. 4 l. 17. In a matrix system,
the water insoluble polymer is mixed together with the
drug and compacted into a tablet:
    [T]he drug substance, optionally a binder such as
    PVP, a dissolution rate controlling polymer (if
    used), and optionally other pharmaceutically ac-
    ceptable excipients are blended together in a
    planetary mixer or a high shear granulator such
    as Fielder and granulated by adding/spraying a
    granulating fluid such as water or alcohol. The
    wet mass can be extruded and spheronized to
    produce spherical particles (beads) using an ex-
    truder/marumerizer.
Id. at col. 6 ll. 23–31.
    Although the specification discloses two different ex-
tended release formulations, the claims are not expressly
limited to a specific formulation by name (i.e., “membrane
system” or “matrix system”), as demonstrated by repre-
sentative claim 1:
        1. A pharmaceutical dosage form comprising
    a population of extended release beads, wherein
    said extended release beads comprise:
        an active-containing core particle comprising
    cyclobenzaprine hydrochloride as the active; and
         an extended release coating comprising a wa-
    ter insoluble polymer membrane surrounding said
    core, wherein said water insoluble polymer mem-
    brane comprises a polymer selected from the
    group consisting of ethers of cellulose, esters of
    cellulose, cellulose acetate, ethyl cellulose, polyvi-
    nyl acetate, neutral copolymers based on ethyl
    acrylate and methyl methacrylate, copolymers of
    acrylic and methacrylic acid esters with quater-
    nary ammonium groups, pH-insensitive ammonio
APTALIS PHARMATECH, INC.   v. APOTEX INC.                5



    methacrylic acid copolymers, and mixtures there-
    of;
        wherein the total amount of cyclobenzaprine
    hydrochloride in the pharmaceutical dosage form
    is 30 mg;
        wherein following a single oral administration
    of the pharmaceutical dosage form, the pharma-
    ceutical dosage form provides a maximum blood
    plasma concentration (Cmax) of 19.851±5.8765
    ng/mL of cyclobenzaprine HCl and an AUC0-168 of
    736.60±259.414 ng·hr/mL.
Id. at col. 10 ll. 23–45 (emphasis added).
    After Apotex filed an Abbreviated New Drug Applica-
tion seeking to produce and market a generic version of
AMRIX®, 2 Aptalis sued Apotex for infringing claims 1, 2,
and 5 of the ’199 patent, as well as claims 14, 16, and 17
of the ’121 patent. Apotex argued that it does not infringe
because its products contain a matrix-style formulation.
    The parties’ dispute centers on the construction of “an
extended release coating comprising a water insoluble
polymer membrane surrounding said core,” which is found
in every asserted claim. Before the district court issued
its claim construction order, the parties stipulated to a
construction for part of the disputed term. They agreed
that “a water insoluble polymer membrane surrounding
said core” means “a water insoluble polymer covering that
surrounds the active core.” J.A. 1619. The district court
subsequently construed “extended release coating,” the
remainder of the disputed claim term, as “[a] layer of any



    2  The asserted patents are listed in the FDA’s Ap-
proved Drug Products with Therapeutic Equivalence
Evaluations for Aptalis’ AMRIX® extended release prod-
uct.
6                   APTALIS PHARMATECH, INC.   v. APOTEX INC.



substance that is applied onto the surface of another, the
purpose of which is to delay the release of a drug in order
to maintain the drug at therapeutically effective concen-
trations over an extended period of time.” J.A. 23. Apply-
ing this claim construction, the district court found that
Apotex’s ANDA product contained an extended release
coating and infringed the asserted claims of the ’199 and
’121 patents. Aptalis Pharmatech, Inc. v. Apotex Inc.,
220 F. Supp. 3d 544, 550–55 (D. Del. 2016) (“Dist. Ct.
Op.”).
    Apotex appealed the district court’s claim construction
and its infringement finding. We have jurisdiction pursu-
ant to 28 U.S.C. § 1295(a)(1).
                            II.
    Claim construction seeks to ascribe the “ordinary and
customary meaning” to claim terms as a person of ordi-
nary skill in the art would have understood them at the
time of invention. Phillips v. AWH Corp., 415 F.3d 1303,
1312–14 (Fed. Cir. 2005) (en banc) (citing Vitronics Corp.
v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996)).
“Where the district court’s claim construction relies only
on intrinsic evidence, the construction is a legal determi-
nation reviewed de novo.” Ruckus Wireless, Inc. v. Inno-
vative Wireless Sols., LLC, 824 F.3d 999, 1002 (Fed. Cir.
2016) (citing Teva Pharm. USA, Inc. v. Sandoz, Inc.,
135 S. Ct. 831, 841 (2015)).
    When construing claims, “there is sometimes a fine
line between reading a claim in light of the specification,
and reading a limitation into the claim from the specifica-
tion.” Comark Commc’ns, Inc. v. Harris Corp., 156 F.3d
1182, 1186 (Fed. Cir. 1998). This case tiptoes that line.
The specification does not provide a lexicographic defini-
tion of “coating,” and the prosecution history contains no
clear and unmistakable disavowal of claim scope. None-
theless, Apotex contends that the intrinsic evidence would
have taught an ordinarily skilled artisan at the time of
APTALIS PHARMATECH, INC.   v. APOTEX INC.                 7



the invention that an “extended release coating” is limited
to a continuous outer film, not simply “[a] layer of any
substance that is applied onto the surface of another.”
For the reasons explained below, we agree and adopt
Apotex’s proposed construction of “extended release
coating” as “a continuous outer film applied onto the
surface of the active-containing core to provide an extend-
ed release of the active core.” See Appellants Br. 21.
    We begin, as we must, with the plain claim language.
Phillips, 415 F.3d at 1312 (“[T]he claims are ‘of primary
importance[] in the effort to ascertain precisely what it is
that is patented.’” (quoting Merrill v. Yeomans, 94 U.S.
568, 570 (1876)). Here, the claim language recites an
“extended release coating comprising a water insoluble
polymer membrane surrounding said [active-containing]
core.” ’199 patent col. 10 ll. 28–29 (emphases added). It is
clear that the coating must surround the core. As the
district court recognized, dictionaries define “surround” as
“to enclose on all sides.” Dist. Ct. Op., 220 F. Supp. 3d at
548 n.10. 3 A coating that surrounds the core or encloses it
on all sides connotes a continuous coating, i.e., one that
covers the entire surface of the core. And, because the
extended release coating must surround the core, the
plain claim language suggests that the coating must be
located outside of the core. In other words, the water
insoluble polymer membrane is an outer coating relative
to the core. Our construction reflects these limitations by
requiring a “continuous outer film applied onto the sur-
face of the active-containing core.”




   3    The parties do not dispute that “surrounding,” as
used in the ’199 patent, means “to enclose on all sides”;
instead, they dispute whether “surround” means that the
coating must be “continuous.” See Appellants Br. 22;
Appellees Br. 39.
8                     APTALIS PHARMATECH, INC.    v. APOTEX INC.



     The specification bolsters our conclusion that the ex-
tended release coating must be a continuous outer film.
See Phillips, 415 F.3d at 1315 (“[T]he specification ‘is
always highly relevant to the claim construction analy-
sis.’” (internal citation omitted)). First, every embodiment
in the specification that discusses a coating describes a
process in which the water insoluble polymer coating is
external to the active-containing core. See, e.g., ’199
patent col. 4 ll. 15–17 (“ER Beads can be produced by
applying a functional membrane comprising a water
insoluble polymer alone or in combination with a water
soluble polymer onto IR Beads.”); id. at col. 5 ll. 38–41
(“The [active]-containing particle may be coated with an
extended release (ER) coating comprising a water insolu-
ble polymer or a combination of a water insoluble polymer
and a water soluble polymer to provide ER beads.”); id. at
col. 4 ll. 33–36 (“ER beads include a core particle (IR
(immediate release) bead) containing a skeletal muscle
relaxant and an ER (extended release) coating comprising
a water insoluble polymer surrounding the core.”); id. at
col. 5 ll. 60–64 (describing process of “coating the IR bead
with a plasticized water-insoluble polymer alone such as
ethylcellulose or in combination with a water soluble
polymer such as hydroxypropylmethylcellulose to form an
Extended Release (ER) bead”); id. at col. 7 ll. 32–35 (dis-
closing the step of “coating the active drug particle with a
solution or suspension of a water insoluble polymer or a
mixture of water soluble and water insoluble polymers to
form an extended release coated drug particle (ER
beads)”). The same is true for Example 2, which describes
spraying an extended release polymer membrane “onto
the IR beads for a weight gain of approximately 10%.” Id.
at col. 8 ll. 39–43; see id. at col. 8 l. 62 – col. 9 l. 13 (dis-
cussing Example 3’s application of extended release
coating onto immediate release beads until a certain
weight gain is reached).
APTALIS PHARMATECH, INC.   v. APOTEX INC.                  9



    These disclosures would have taught a person of ordi-
nary skill that the extended release coating is an outer
coating of polymer relative to the active-containing core. 4
And the specification’s frequent references to applying the
extended release coating “onto” the active-containing core
comports with our understanding of the spatial orienta-
tion required by the claims. See, e.g., id. at col. 3 ll. 64–
67, col. 4 ll. 15–17, col. 8 ll. 39–43, col. 8 ll. 62–66.
    Second, the specification demonstrates the inventors’
ability to describe a non-continuous coating when they so
desired. The specification’s background of the invention



    4     The specification’s disclosure of an extended re-
lease matrix formulation does give us pause. See id. at
col. 6 ll. 23–33 (describing an embodiment where the rate-
controlling polymer is blended together with the active
drug and compressed into beads, as opposed to spraying
the rate controlling polymer onto an active-containing
core). But while a construction that excludes a preferred
embodiment “is rarely, if ever, correct,” Vitronics Corp.,
90 F.3d at 1583, “[t]his does not mean . . . that each and
every claim ought to be interpreted to cover each and
every embodiment,” PPC Broadband, Inc. v. Corning
Optical Commc’ns RF, LLC, 815 F.3d 747, 755 (Fed. Cir.
2016). We note that the specification describes the steps
in this embodiment as “blend[ing],” “granulat[ing],”
“extrud[ing],” and “spheroniz[ing].” Id. at col. 6 ll. 26–30.
The other embodiments and the claims, however, require
a “coating”; and, in any event, nothing in the specification
forbids the application of an extended release coating onto
this matrix embodiment. See Oral Arg. at 28:44–30:29,
http://oralarguments.cafc.uscourts.gov/default.aspx?fl=20
17-1344.mp3. Thus, this does not alter our conclusion
that the specification, when read as a whole, would have
taught an ordinarily skilled artisan that an “extended
release coating” requires a continuous outer film.
10                  APTALIS PHARMATECH, INC.   v. APOTEX INC.



section referred to a prior art reference that disclosed the
application of a water impermeable coating onto a core
followed by the creation of apertures in the coating. The
inventors of the asserted patents described the coating in
this prior art reference as “ha[ving] apertures exposing
between about 5–75% of the core surface.” Id. at col. 2
ll. 30–31. By contrast, the asserted claims require the
coating to “surround[] said core.” The inventors’ decision
to claim a coating that surrounds the core instead of
claiming a coating with a certain percentage of exposed
core surface would have informed a person of ordinary
skill in the art that the claims require a continuous
coating.
    The prosecution history offers additional support for
construing “extended release coating” to require a contin-
uous outer film. See Markman v. Westview Instruments,
Inc., 52 F.3d 967, 980 (Fed. Cir. 1995) (en banc) (“To
construe claim language, the court should also consider
the patent’s prosecution history, if it is in evidence.”).
During prosecution of the ’199 patent, the applicants
submitted a declaration from Dr. James W. McGinity.
The Declaration summarizes Dr. McGinity’s interview
with the examiner during the prosecution of a related
patent application that shares the same specification as
the asserted patents. According to Dr. McGinity, the
process taught by the shared specification results in the
formation of a continuous film:
         If the liquid medium used in the coating pro-
     cess contains the polymer suspended as an aque-
     ous dispersion, the polymer is initially deposited
     onto the core as discrete polymer spheres, which
     must then coalesce to form a continuous film. In
     such cases, a plasticizer may be added to the liq-
     uid medium to facilitate the coalescence process.
     On the other hand, if the liquid medium contains
     the polymer dissolved as a solution in an organic
APTALIS PHARMATECH, INC.   v. APOTEX INC.                 11



    solvent, a continuous film forms directly upon
    evaporation of the solvent.
J.A. 1140–41, ¶ 9(c) (emphases added). A person of ordi-
nary skill reading this Declaration would have understood
that the extended release coatings of the invention were
continuous films. And an ordinarily skilled artisan would
have understood the film to be an outer layer relative to
the core because the coating is “deposited onto” the cores.
     We are not persuaded by Aptalis’ arguments in de-
fense of the district court’s contrary construction. Aptalis
first argues that the “applied onto the surface of the
active-containing core” and “outer” requirements would
exclude preferred embodiments. In Example 2, for in-
stance, a seal coat is applied onto the active-containing
core before the extended release coating, and an addition-
al coating layer is added after the extended release coat-
ing. See ’199 patent col. 8 ll. 23–46. Because there is a
seal coat between the extended release coating and the
active-containing core, Aptalis argues that the extended
release coating was applied onto the seal coat, not “onto
the surface of the active-containing core.” Similarly,
Aptalis interprets “outer” to mean “outermost” and points
out that there is a coating layer applied onto the extended
release coating in Example 2.
    Neither argument is persuasive. The specification re-
fers to seal-coated active-containing cores as “core[s],” id.
at col. 7 ll. 4–14, so the presence of a seal coat does not
mean that the extended release coating is not applied
“onto the surface of the active-containing core.” And
although Aptalis is correct that there is no basis for
requiring the extended release coating to be the “outer-
most” coating, our construction imposes no such require-
ment. The extended release coating need only be an outer
coating relative to the active-containing core, which is
consistent with Example 2’s teachings.
12                   APTALIS PHARMATECH, INC.   v. APOTEX INC.



    Aptalis next asserts that the word “continuous” does
not appear in the asserted patents and that a “continu-
ous” extended release coating would not be functional
because the coating must be permeable to gastrointestinal
fluids. Aptalis conflates continuity with permeability, as
demonstrated by Dr. McGinity’s Declaration:
          Extended release drug products may be made
     by coating water-insoluble polymers (e.g., the wa-
     ter-insoluble polymers claimed by Applicants) on-
     to a core containing the active drug. In general,
     the applied polymer coatings do not dissolve when
     the drug product is ingested; instead, the coatings
     are semi-permeable such that water can enter and
     exit the core, thereby releasing the dissolved drug
     at a controlled rate.
J.A. 1140, ¶ 9(a) (emphasis added). It follows that a
continuous film covering the surface of the active-
containing core would not defeat the extended release
functionality because the polymer coatings described by
the invention are semi-permeable to water.
    Finally, Aptalis contends that the prosecution history
is irrelevant to the claim construction question here
because there is no clear and unmistakable disavowal of
claim scope. Our precedent does not support this proposi-
tion. We have stated that “[a]ny explanation, elaboration,
or qualification presented by the inventor during patent
examination is relevant, for the role of claim construction
is to ‘capture the scope of the actual invention’ that is
disclosed, described, and patented.” Fenner Invs., Ltd. v.
Cellco P’ship, 778 F.3d 1320, 1323 (Fed. Cir. 2015) (quot-
ing Retractable Techs., Inc. v. Becton, Dickinson & Co.,
653 F.3d 1296, 1305 (Fed. Cir. 2011)). Although the
prosecution history may lack the clarity imbued by the
specification, it “can often inform the meaning of the
claim language by demonstrating how the inventor un-
derstood the invention and whether the inventor limited
APTALIS PHARMATECH, INC.   v. APOTEX INC.               13



the invention in the course of prosecution, making the
claim scope narrower than it would otherwise be.” Phil-
lips, 415 F.3d at 1317. Accordingly, even in the absence of
a clear and unmistakable disavowal, we conclude that the
prosecution history can be evaluated to determine how a
person of ordinary skill would understand a given claim
term.
                             III.
    We have considered the parties’ remaining claim con-
struction arguments and find them unpersuasive. Be-
cause we conclude that the district court erred in
construing the claims, we vacate and remand the district
court’s infringement finding for further proceedings
consistent with our claim construction.
             VACATED AND REMANDED
                           COSTS
    Costs to Appellants.
