Bracco Diagnostics Inc. v. Maia Pharmaceuticals, Inc. ( 2020 )


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  • Case: 20-1387    Document: 54    Page: 1   Filed: 12/17/2020
    NOTE: This disposition is nonprecedential.
    United States Court of Appeals
    for the Federal Circuit
    ______________________
    BRACCO DIAGNOSTICS INC.,
    Plaintiff-Appellee
    v.
    MAIA PHARMACEUTICALS, INC.,
    Defendant-Appellant
    ______________________
    2020-1387
    ______________________
    Appeal from the United States District Court for the
    District of New Jersey in No. 3:17-cv-13151-PGS-TJB, Sen-
    ior Judge Peter G. Sheridan.
    ______________________
    Decided: December 17, 2020
    ______________________
    WILLIAM R. ZIMMERMAN, Knobbe, Martens, Olson &
    Bear, LLP, Washington, DC, argued for defendant-appel-
    lant. Also represented by THOMAS P. KRZEMINSKI, KAREN
    MARIE CASSIDY, Irvine, CA.
    DONALD RHOADS, Rhoads Legal Group PC, New York,
    NY, argued for plaintiff-appellee. Also represented by H.
    DANNY KAO, Kao & Associates, Pc, Flushing, NY.
    ______________________
    Case: 20-1387    Document: 54      Page: 2   Filed: 12/17/2020
    2     BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.
    Before LOURIE, CLEVENGER, and CHEN, Circuit Judges.
    LOURIE, Circuit Judge.
    Maia Pharmaceuticals, Inc. (“Maia”) appeals from a
    judgment of the United States District Court for the Dis-
    trict of New Jersey that Maia’s sincalide product infringes
    U.S. Patent 6,803,046 (“the ’046 patent”), owned by Bracco
    Diagnostics, Inc. (“Bracco”). J.A. 1–8. The court entered
    the judgment pursuant to a stipulation of infringement by
    the parties in view of the court’s claim construction of the
    terms buffer, surfactant/solubilizer, and surfactant.
    Bracco Diagnostics, Inc. v. Maia Pharms., Inc., No. 3:17-cv-
    13151, 
    2019 WL 4885888
    (D.N.J. Oct. 3, 2019) (“Claim
    Construction Order”). Because Maia stipulated to infringe-
    ment under a claim construction that is essentially correct,
    we affirm.
    BACKGROUND
    This appeal concerns a patent infringement action
    brought by Bracco under the Hatch-Waxman Act. Bracco
    owns the ’046 patent, listed in the Food and Drug Admin-
    istration’s (FDA) Orange Book as covering Kinevac®, the
    active ingredient of which is sincalide. The ’046 patent has
    claims directed to sincalide formulations, methods for mak-
    ing and using sincalide formulations, and sincalide powder
    kits. ’046 patent col. 37 l. 40–col. 44 l. 30. Sincalide, a
    synthetic peptide hormone, is typically administered to
    stimulate gallbladder contraction, stimulate pancreatic se-
    cretion, and accelerate the transit of a barium meal
    through the small bowel. J.A. 79–80, 191; ’046 patent col.
    13 ll. 40–58. Although sincalide was originally introduced
    in 1976, the ’046 patent purports to teach sincalide formu-
    lations that are “purer than prior art formulations, and
    have fewer degradants and more consistent potency” in
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    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.      3
    part through addition of excipients 1 such as buffers, sur-
    factants/solubilizers, and surfactants. ’046 patent col. 1 ll.
    9–26, 46–49. All 36 claims at issue in this litigation require
    sincalide, a buffer, and, depending on the claim, either a
    surfactant/solubilizer or a surfactant.
    Id. col. 37 l.
    40–col.
    40 l. 44.
    In 2017, Maia filed a New Drug Application (“NDA”)
    for its own sincalide product pursuant to FDCA § 505(b)(2).
    It is undisputed that Maia’s sincalide product contains
    amino acid excipients. Maia certified pursuant to §
    505(b)(2)(A)(iv) that its sincalide product would not in-
    fringe the ’046 patent claims. Bracco filed suit in December
    2017, alleging that Maia’s product does infringe the claims.
    Maia denied infringement, asserting that the amino acid
    excipients in its sincalide product do not act as buffers, sur-
    factants/solubilizers, or surfactants, as required by the
    claims. Maia also counterclaimed that the claims are inva-
    lid. The parties requested that the district court construe
    the terms buffer, surfactant/solubilizer, and surfactant.
    Central to the claim construction dispute was whether the
    three terms encompass amino acids.
    Claim 1 reads as follows:
    1. A stabilized, physiologically acceptable formula-
    tion of sincalide comprising:
    (a) an effective amount of sincalide,
    (b) at least one stabilizer,
    1  Although both parties reference “excipients” through-
    out their briefs, neither party defines the term. We accept
    the construction proposed by the district court: “An inac-
    tive substance that serves as the vehicle or medium for a
    drug or other active substance.” Claim Construction Order,
    
    2019 WL 4885888
    , at *2 n.1 (citing Oxford English Diction-
    ary).
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    4     BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.
    (c) a surfactant/solubilizer
    (d) a chelator,
    (e) a bulking agent/tonicity adjuster, and
    (f) a buffer.
    ’046 patent col. 37 ll. 41–49 (emphases added).
    Several dependent claims contain “Markush” groups
    that further recite that buffers or surfactants/solubilizers
    can be selected from a list of excipients that includes amino
    acids. A Markush group “lists alternative species or ele-
    ments that can be selected as part of the claimed inven-
    tion.” Multilayer Stretch Cling Film Holdings, Inc. v. Berry
    Plastics Corp., 
    831 F.3d 1350
    , 1357 (Fed. Cir. 2016) (citing
    Abbott Labs. v. Baxter Pharm. Prods., Inc., 
    334 F.3d 1274
    ,
    1280 (Fed. Cir. 2003)).
    Claim 3 depends from claim 1, and recites that an
    amino acid can be selected as a buffer:
    3. The formulation of claim 1, wherein said buffer
    is selected from the group consisting of . . . one or
    more amino acids . . . and biological buffers.
    ’046 patent col. 37 ll. 51–60 (emphases added).
    Claim 6 depends from claim 1 and recites that an
    amino acid can be selected as a surfactant/solubilizer:
    6. The formulation of claim 1, wherein said surfac-
    tant/solubilizer is selected from the group consist-
    ing of . . . amino acids.
    Id. col. 37 l.
    65–col. 38 l. 5 (emphases added).
    Claim 40 is to a kit, where a powder mixture contains
    a surfactant:
    40. A kit, comprising:
    (i) a powder mixture comprising
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    BRACCO DIAGNOSTICS INC.     v. MAIA PHARMACEUTICALS, INC.   5
    (a) sincalide,
    (b) at least one stabilizer,
    (c) a surfactant,
    (d) a chelator,
    (e) a bulking agent/tonicity ad-
    juster, and
    (f) a buffer;
    (ii) a container to hold said powder mix-
    ture; and
    (iii) optionally, a physiologically acceptable
    fluid.
    Id. col. 39 ll.
    53–62 (emphasis added).
    Claim 44 depends from claim 40 and recites that an
    amino acid can be selected as a surfactant:
    44. The kit of claim 40, wherein said surfactant is
    selected from the group consisting of . . . amino ac-
    ids.
    Id. col. 40 ll.
    10–18 (emphases added).
    The specification provides further context regarding
    the meaning of the three terms. For example, the specifi-
    cation explains that buffers “are employed to stabilize the
    pH of sincalide formulations of the invention, and conse-
    quently, reduce the risk of chemical stability 2 at extreme
    pH values.”
    Id. col. 9 ll.
    45–47. The specification provides
    a nonexclusive list of buffering agents “useful in the prep-
    aration of formulation kits,” which includes amino acids.
    Id. col. 9 ll.
    48–65. The list of exemplary buffering agents
    in the specification is substantially similar to the buffering
    2   We presume that this is a typographical error and
    the patentee intended to write “instability.”
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    6     BRACCO DIAGNOSTICS INC.    v. MAIA PHARMACEUTICALS, INC.
    agents listed in the dependent claims for buffer. See, e.g.
    , id. col. 37 ll.
    51–60.
    The specification also includes a section entitled “Sur-
    factants/Solubilizers/Surface Active Agents,” which ex-
    plains that “[t]he addition of a nonionic surfactant . . . may
    reduce the interfacial tension or aid in solubilization thus
    preventing or reducing denaturation and/or degradation at
    air/liquid or liquid/solid interfaces of the product in solu-
    tion.”
    Id. col. 11 ll.
    26–34. The specification further pro-
    vides      two     non-exclusive        exemplary  lists    of
    surfactants/solubilizers, which include amino acids.
    Id. col. 11 ll.
    35–63. The lists of exemplary surfactants/solu-
    bilizers in the specification overlap with the dependent
    claims for surfactants/solubilizers and surfactants. E.g.
    , id. col. 37 l.
    65–col. 38 l. 5, col. 40 ll. 11–18.
    With respect to the term buffer, the district court
    adopted the following construction:
    An excipient that: stabilizes the pH of sincalide for-
    mulations of the invention, and consequently, re-
    duces the risk of chemical stability at extreme pH
    values. Buffering agents useful in the preparation
    of formulation kits of the invention include phos-
    phoric acid, phosphate (e.g. monobasic or dibasic
    sodium phosphate, monobasic or dibasic potassium
    phosphate, etc.), citric acid, citrate (e.g. sodium cit-
    rate, etc.), sulfosalicylate, acetic acid, acetate (e.g.
    potassium acetate, sodium acetate, etc.), methyl
    boronic acid, boronate, disodium succinate hexahy-
    drate, amino acids, including amino acid salts
    (such as histidine, glycine, lysine, imidazole), lactic
    acid, lactate (e.g. sodium lactate, etc.), maleic acid,
    maleate, potassium chloride, benzoic acid, sodium
    benzoate, carbonic acid, carbonate (e.g. sodium car-
    bonate, etc.), bicarbonate (e.g. sodium bicarbonate,
    etc.), boric acid, sodium borate, sodium chloride,
    succinic acid, succinate (e.g. sodium succinate),
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    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.       7
    tartaric acid, tartrate (e.g. sodium tartrate, etc.),
    tris(hydroxymethyl) aminomethane, biological
    buffers (such as N-2-hydroxyethylpiperazine, N’-2-
    ethanesulfonic acid (HEPES), CHAPS and other
    ‘Good’s’ buffers).
    Claim Construction Order, 
    2019 WL 4885888
    , at *10 (em-
    phasis added). The district court thus imported into its def-
    inition the list of exemplary buffering agents from the
    specification. It rejected Maia’s proposal to construe the
    term buffer to mean “[a] compound that stabilizes the pH
    of a sincalide formulation.”
    Id. at *3.
          The district court construed the term surfactant/solu-
    bilizer to mean:
    A surfactant and/or a solubilizer. The addition of a
    nonionic surfactant, such as polysorbate, to the for-
    mulation, may reduce the interfacial tension or aid
    in solubilization thus preventing or reducing dena-
    turation and/or degradation at air/liquid or liq-
    uid/solid interfaces of the product in solution.
    Surfactants/solubilizers include compounds such
    as free fatty acids, esters of fatty acids with polyox-
    yalkylene compounds like polyoxypropylene glycol
    and polyoxyethylene glycol; ethers of fatty alcohols
    with polyoxyalkylene glycols; esters of fatty acids
    with polyoxyalkylated sorbitan; soaps; glycerol-pol-
    yalkylene stearate; glycerol polyoxyethylene ricino-
    leate; mono- and copolymers of polyalkylene
    glycols; polyethoxylated soya-oil and castor oil as
    well as hydrogenated derivatives; ethers and esters
    of sucrose or other carbohydrates with fatty acids.
    Fatty alcohols, these being optionally polyoxyalkyl-
    ated; mono-, di-, and triglycerides of saturated or
    unsaturated fatty acids; glycerides or soya-oil and
    sucrose; sodium caprolate, ammonium sulfate, so-
    dium dodecyl sulfate (SDS), Triton-l00 and anionic
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    8     BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.
    surfactants containing alkyl, aryl or heterocyclic
    structures.
    Examples of preferred surfactants/solubilizers for
    use in the present invention include, but are not
    limited to, pluronics (e.g., Lutrol F68, Lutrol F
    127), Poloxamers, SDS, Triton-100, polysorbates
    such as TWEEN® 20 and TWEEN® 80, propylene
    glycol, PEG and similar compounds, Brij58 (poly-
    oxyethylene 20 cetyl ether), cremophor EL, cetyl
    trimethylammonium bromide (CTAB), dimethyla-
    cetamide (DMA), NP-40 (Nonidet p 40), and N-me-
    thyl-2-pyrrolidone (Pharmasolve), glycine and
    other amino acids/amino acid salts and anionic
    surfactants containing alkyl, aryl or heterocyclic
    structures, and cyclodextrins. TWEEN® 20 is the
    most preferred surfactant in formulations of the in-
    vention.
    Id. at *10
    (emphasis added). As it did with the term buffer,
    the court imported a list of preferred surfactants/solubil-
    izers from the specification into its definition of the term.
    It rejected Maia’s proposal to construe surfactant/solubil-
    izer to mean “[a] surfactant that is also a solubilizer. A
    solubilizer is a compound that aids in solubilization, thus
    preventing or reducing sincalide denaturation and/or deg-
    radation cause by peptide aggregation, precipitation, sur-
    face adsorption, or agitation at air/liquid or liquid/solid
    interfaces in solution.”
    Id. at *2.
         Lastly, the district court construed the term surfactant
    to mean “[a]n excipient that may reduce the interfacial ten-
    sion.”
    Id. at *10
    (emphasis added). The court rejected
    Maia’s proposal to construe surfactant to mean “[a] com-
    pound that reduces the tension of the air/liquid or liq-
    uid/solid interface.”
    Id. at *5.
    The court also rejected
    Bracco’s proposal to import a list of exemplary surfac-
    tants/solubilizers from the specification into its definition.
    Id. at *7.
    Case: 20-1387    Document: 54      Page: 9    Filed: 12/17/2020
    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.    9
    In view of the district court’s claim constructions, the
    parties stipulated to infringement of claims 1–3, 6, 10–17,
    19, 21–23, 26, 30–37, 40–41, 44, and 48–55 (“the stipulated
    claims”) and dismissal of the remaining claims and de-
    fenses without prejudice. J.A. 1–8, 3666–3678. The court
    made no evidentiary findings regarding infringement in its
    final judgment. Maia appealed to this court. We have ju-
    risdiction over the appeal pursuant to 28 U.S.C. 1295(a)(1).
    DISCUSSION
    Maia argues that we should vacate the district court’s
    construction of the terms buffer, surfactant/solubilizer, and
    surfactant, adopt Maia’s proposed constructions for the
    terms, and remand to the district court for further proceed-
    ings. At issue in this dispute is whether the district court
    erroneously included amino acids in its definitions of buffer
    and surfactant/solubilizer, erroneously construed the back-
    slash between surfactant/solubilizer to mean “and” or “or,”
    and erroneously included “may” in its definition of surfac-
    tant.
    Claim construction is a question of law that we review
    de novo. Teva Pharm. USA, Inc. v. Sandoz, Inc., 
    135 S. Ct. 831
    , 839 (2015). We review de novo the district court’s find-
    ings of fact on evidence “intrinsic to the patent (the patent
    claims and specifications, along with the patent’s prosecu-
    tion history),” and review for clear error underlying fact
    findings related to extrinsic evidence.
    Id. at 841.
         As an initial matter, we note that the district court did
    not specify in its claim construction order which claims it
    was construing. Claim Construction Order, 
    2019 WL 4885888
    , at *10. However, that does not matter here, as
    we are dealing with the same claim limitations in all of the
    claims, and can readily review their constructions.
    In order to resolve the disputes, we turn to the claim
    language of the stipulated claims. See Phillips v. AWH
    Corp., 
    415 F.3d 1303
    , 1314 (Fed. Cir. 2005) (en banc). Both
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    10   BRACCO DIAGNOSTICS INC.    v. MAIA PHARMACEUTICALS, INC.
    the dependent and independent claims recite the disputed
    terms buffer, surfactant/solubilizer, or surfactant. The
    scope of the dependent claims is expressly defined by nam-
    ing the intended components, through Markush claiming.
    For example, dependent claims 3, 23, and 41 recite that a
    “buffer is selected from the group consisting of a [list of ex-
    cipients, including amino acids].” ’046 patent col. 37 ll. 51–
    60, col. 38 ll. 58–67, col. 39 l. 63–col. 40 l. 5. The dependent
    claims that recite a surfactant and a surfactant/solubilizer
    are substantially similar. See, e.g.
    , id. col. 39 ll.
    5–12
    (“[S]urfactant/solubilizer is selected from the group con-
    sisting of . . . .”), col. 41 ll. 5–12 (“[S]urfactant is selected
    from the group consisting of . . . .”). The Markush groups
    are “closed” because “[u]se of the transitional phrase ‘con-
    sisting of’ to set off a patent claim element” indicates that
    the claim “exclude[s] any elements, steps, or ingredients
    not specified in the claim.” 
    Multilayer, 831 F.3d at 1358
     (quoting AFG Indus., Inc. v. Cardinal IG Co., 
    239 F.3d 1239
    , 1245 (Fed. Cir. 2001)). Thus, the dependent claims
    need no formal construction because, through the Markush
    claim drafting, the possible components are named and the
    scope of the dependent claims is thus definite and clear.
    The independent claims also recite use of buffers, sur-
    factants/solubilizers, and surfactants in sincalide formula-
    tions, methods of making sincalide formulations, and
    sincalide kits. See, e.g., ’046 patent col. 37 ll. 41–49, col. 38
    ll. 51–55, col. 39 ll. 53–62. However, unlike the dependent
    claims, the scope of the independent claims is not expressly
    defined by naming the possible components. We will there-
    fore construe the district court’s claim constructions as ap-
    plicable to the disputed independent claims.
    I. Buffer
    Maia argues that the district court wrongly imported
    a list of exemplary buffers from the specification into its
    definition of the term buffer. Maia asserts that the plain
    and ordinary meaning of buffer within the context of the
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    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.    11
    patent specification is functional: “a compound 3 that stabi-
    lizes the pH of a sincalide formulation.” Appellant Br. at
    43–44 (emphasis added); see also ’046 patent col. 9 ll. 45–
    47 (“Buffering agents are employed to stabilize the pH of
    sincalide formulations of the invention . . . .”) (emphasis
    added). According to Maia, the court eliminated the func-
    tional aspect of buffer by construing it to include excipients
    such as amino acids that do not necessarily have buffering
    effects. Maia asserts that the court’s broad construction of
    buffer is contrary to its plain and ordinary meaning.
    Maia emphasizes that its amino acids do not have buff-
    ering effects. It asserts, however, that because the district
    court defined buffer broadly to necessarily include all
    amino acids, even those that do not actually act as buffers,
    it had no choice but to stipulate to infringement. Maia ef-
    fectively interprets the court’s construction to mean: an ex-
    cipient that stabilizes the pH of a sincalide formulation and
    consequently, reduces the risk of chemical [in]stability at
    extreme pH values or [all amino acids regardless of func-
    tion]. Appellant Rep. Br. at 22. In other words, Maia does
    not consider the stipulation to be an admission that its
    amino acids actually function to stabilize the pH of a sin-
    calide formulation. Rather, the stipulation is only an ad-
    mission that Maia’s product has amino acids. Maia thus
    argues that if this court removes the “predetermined” list
    of excipients, which includes amino acids, from the defini-
    tion of buffer, we would need to remand the case for an in-
    fringement analysis as to whether Maia’s amino acids have
    buffering effects.
    Bracco responds that the district court properly defined
    buffer to include a list of excipients from the specification.
    3    Maia’s proposed construction refers to a buffer as a
    compound. Appellant Br. at 43–44. The court construed
    buffer to be an “excipient.” According to Maia, the distinc-
    tion is not material to the case. Appellant Rep. Br. at 16.
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    12   BRACCO DIAGNOSTICS INC.    v. MAIA PHARMACEUTICALS, INC.
    Bracco first argues that the specification provides a list of
    excipients, including amino acids, that the “inventors used
    to define” buffer, and therefore the list must be included in
    the definition of buffer. Appellee Br. at 27 (citing ’046 pa-
    tent col. 9 ll. 45–65). Bracco also points to dependent
    claims, like claim 3, which recite that “a buffer is selected
    from the group consisting of” a substantially similar list of
    exemplary buffers as those listed in the specification. Ap-
    pellee Br. at 27.
    According to Bracco, any error in claim construction is
    harmless. It rejects Maia’s argument that it only stipu-
    lated to having amino acids in its product, not that its
    amino acids have buffering effects. Bracco asserts that
    Maia is misconstruing the district court’s construction of
    the three terms in the stipulation “as somehow reading out
    the functions required by the terms.” Appellee Br. at 16.
    Bracco states that when Maia stipulated to infringement,
    Maia effectively agreed that “each of [its] two amino acids
    is a ‘buffer’ excipient with a ‘buffer’ effect, which is [a]n ex-
    cipient that: stabilizes the pH of sincalide formulations . . .
    .”
    Id. at 16–17.
    Bracco thus argues that the court’s re-
    moval of the exemplary list has no effect on the infringe-
    ment analysis. Maia is foreclosed, Bracco argues, from
    asserting that its amino acids do not have buffering effects
    in view of the stipulation. Bracco also asserts that extrinsic
    evidence demonstrates that Maia’s amino acids function as
    buffers. However, Bracco does not cite any portion of the
    claim construction order or final judgment demonstrating
    that the court took into account evidentiary findings re-
    garding the function of Maia’s amino acids.
    We agree with Maia that the district court technically
    erred in importing a list of excipients into its definition of
    buffer. Listing numerous compounds that meet the lan-
    guage of a functional term in a claim confuses construing
    what the function is with what compounds perform that
    function. The latter is not the task of claim construction,
    which is to provide definitional meaning to claim language.
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    BRACCO DIAGNOSTICS INC.    v. MAIA PHARMACEUTICALS, INC.       13
    The court correctly did that when it stated that a buffer,
    for purposes of this invention, is “[a]n excipient that: stabi-
    lizes the pH of sincalide formulations of the invention, and
    consequently, reduces the risk of chemical [in]stability at
    extreme pH values.” Claim Construction Order, 
    2019 WL 4885888
    , at *10. That construction by the district court
    was correct, and the court’s technical error of then listing
    from the specification a long list of compounds meeting that
    meaning does not invalidate that functional construction.
    And claim 3 then recites that the buffer in claim 1 includes
    one or more amino acids. That technical error was thus
    harmless. Maia then stipulated to infringement.
    The key language of its stipulation reads as follows:
    “Under the Court’s construction of the disputed claim
    terms of the ’046 patent, . . . Maia’s 505(b)(2) NDA Product
    would literally infringe the 36 claims.” J.A. 3673; see also
    J.A. 5–6. That stipulation forecloses the argument for non-
    infringement.
    Maia argues that it had no choice but to stipulate to
    infringement because the district court’s construction re-
    moved the functional aspect of buffer and predetermined
    that Maia’s amino acids have buffering effects. But the dis-
    trict court did not “remove” the functional definition of
    buffer. The court correctly included the functional defini-
    tion in its claim construction. Maia asks us to effectively
    reinterpret the court’s construction to mean: an excipient
    that stabilizes the pH . . . buffering agents to include . . .
    [all amino acids regardless of function]. But that was not
    the stipulation.
    Maia also points to a “whereas” clause in the stipula-
    tion stating that “the [district court’s] construction, explic-
    itly defining ‘buffer’ . . . to include ‘amino acids,’ alone forms
    the basis for Maia’s admission and stipulation.” Appellant
    Rep. Br. at 23 (citing J.A. 3671) (emphasis added). But that
    is also not what the stipulation says, and we do not rely on
    a self-serving “whereas” clause to override the clear import
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    14   BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.
    of the statement. That clause is directly contradictory to
    Maia’s admission in the other portion of the stipulation
    that its product meets “every element and claim term” of
    the claims. J.A. 3669. Moreover, even Maia admits that
    the “whereas” clause is neither binding nor conclusive. Ap-
    pellant Rep. Br. at 23.
    Maia similarly argued that the claims are invalid as
    inoperable, because, it asserts, amino acids are not buffers.
    However, it relinquished those arguments when it stipu-
    lated to infringement and dismissal of its counterclaims of
    invalidity. J.A. 6, 3673. Consequently, contrary to Maia’s
    assertion, it did have an opportunity to assert that its
    amino acids do not function as “buffering agents” because
    they do not “stabilize the pH.” To the extent that Maia be-
    lieved the district court’s construction had a particular
    meaning, it never sought clarification from the court, and
    that issue, in light of the stipulation, is now beyond the
    scope of this appeal. J.A. 3670. Having entered into a stip-
    ulation, Maia is now bound by it. See Inventio AG v. Otis
    Elevator Co., 497 F. App’x 37, 41 (Fed. Cir. 2012) (rejecting
    a party’s argument that it did not stipulate to a certain fact
    because the wording of the stipulation “suggests otherwise,
    and it is to that stipulation [the party] is bound”); United
    States v. Penland, 370 F. App’x 381, 383 (4th Cir. 2010) (re-
    jecting party’s attempt to disavow “unambiguous language
    set forth in the [s]tipulation”); United States v. Kieffer, 
    794 F.3d 850
    , 852 (7th Cir. 2015) (asserting that a party “may
    not disavow [its] stipulations by quibbling over seman-
    tics”).
    Because the district court’s claim construction is essen-
    tially correct and Maia stipulated to infringement if that
    were so, we affirm the judgment of infringement without
    remand. See, e.g., SUFI Network Servs., inc. v. United
    States, 
    755 F.3d 1305
    , 1312 (Fed. Cir. 2014) (remand can
    be unnecessary where “no further record development is
    appropriate”); Shinyei Corp. of Am. v. United States, 
    524 F.3d 1274
    , 1284 n.3 (Fed. Cir. 2008) (holding that “because
    Case: 20-1387    Document: 54      Page: 15     Filed: 12/17/2020
    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.     15
    the issues on appeal are legal, not factual, we see no need
    to remand”).
    II. Surfactant/Solubilizer
    We turn next to Maia’s argument that the district court
    erred in construing the term surfactant/solubilizer. Maia
    again argues here that the court wrongly imported a list of
    exemplary surfactants/solubilizers from the specification
    into the definition. Maia also argues that the court improp-
    erly construed the backslash between surfactant/solubil-
    izer to mean “and” or “or” rather than “and.” We address
    each argument in turn.
    With regard to the first issue, Maia argues that the dis-
    trict court “eviscerated” the functional aspect of the term
    surfactant/solubilizer by importing a list of exemplary ex-
    cipients into its definition regardless as to whether they ac-
    tually function as such. We agree with Maia that the
    district court technically erred in importing a list of excip-
    ients into its definition of surfactant/solubilizer. But, as
    with the term buffer, inclusion of the list of exemplary sur-
    factant/solubilizer agents, while technically incorrect, is es-
    sentially correct in its functional definition. As a result,
    the court’s technical error is harmless.
    Our analysis here is similar to our analysis regarding
    the district court’s error in construing buffer. The district
    court correctly included the functional definition in its
    claim construction. Its construction reads that a surfac-
    tant/solubilizer “may reduce the interfacial tension or aid
    in solubilization thus preventing or reducing denaturation
    and/or degradation at air/liquid or liquid/solid interfaces of
    the product in solution.” Claim Construction Order, 
    2019 WL 4885888
    , at *10. Inclusion of the sentence “the addi-
    tion of a nonionic surfactant, such as polysorbate,” along
    with an exemplary list of surfactant/solubilizer agents,
    does not invalidate the functional portion of the construc-
    tion. Moreover, as with buffer, claim 6 recites that the sur-
    factant/solubilizer includes amino acids. ’046 patent col. 37
    Case: 20-1387    Document: 54     Page: 16    Filed: 12/17/2020
    16   BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.
    l. 65–col. 38 l. 5. Maia’s product includes amino acids and
    thus it stipulated to infringement. When Maia stipulated
    to infringement under the court’s claim construction, it
    stipulated to infringing every limitation of the claims, not
    just to having amino acids. Having entered into a stipula-
    tion, Maia is bound by it.
    We now turn to Maia’s second argument. Maia argues
    that the district court wrongly construed surfactant/solu-
    bilizer to mean a surfactant “and” or “or” a solubilizer, ra-
    ther than a surfactant that is also a solubilizer. As support
    for its position, Maia argues that the specification sets
    forth a pattern of using a backslash to describe one excipi-
    ent that has multiple functions. For example, in Table 1,
    mannitol is reported to function as a “bulking agent/cake
    forming agent/tonicity adjuster.” ’046 patent cols. 3–4 Ta-
    ble 1. According to Maia, the table indicates that mannitol
    is a bulking agent [and] cake forming agent [and] tonicity
    adjuster. Appellant Br. at 34. Maia further argues that
    the district court’s construction of “surfactant/solubilizer”
    to mean a surfactant or solubilizer would allow the claims
    to encompass sincalide formulations without surfactants.
    According to Maia, that impermissibly broadens the scope
    of the claims beyond that supported by the specification be-
    cause every embodiment and description of the invention
    in the patent requires a surfactant. Maia points to Table 1
    and example 7, both of which include sincalide formula-
    tions comprising surfactants, and statements in the speci-
    fication that the formulation includes a surfactant.
    Bracco responds that the specification supports its con-
    struction of the backslash to mean “and” or “or.” With re-
    spect to Maia’s argument that the specification only
    discloses embodiments comprising surfactants, Bracco ar-
    gues that Maia attempts to impermissibly read preferred
    embodiments into the claim. It asserts that the patent’s
    disclosure contains no disclaimer of sincalide formulations
    without surfactants and that, on the contrary, there are
    several examples of formulations in the specification that
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    BRACCO DIAGNOSTICS INC.    v. MAIA PHARMACEUTICALS, INC.        17
    do not contain surfactants, including those described in ta-
    bles 8 and 9. With regard to Maia’s argument that the
    specification uses the backslash in Table 1 to define a sin-
    gle excipient that has more than one function, Bracco as-
    serts that the backslash could also be construed in that
    context to mean “or.” For example, in Table 1, mannitol
    can be a bulking agent [or] a cake forming agent [or] a to-
    nicity adjuster. Appellee Br. at 46.
    We agree with Bracco that the district court correctly
    construed the backslash in surfactant/solubilizer to mean
    “and” or “or.” Beginning with the claim language, the plain
    reading of the claims is that the backslash means “and” or
    “or.” Claim 1, in relevant part recites: “A stabilized, phys-
    iologically acceptable formulation of sincalide comprising:
    . . . (c) a surfactant/solubilizer . . . .” ’046 patent col. 37 ll.
    41–49 (emphasis added). Claim 7 depends from claim 1
    and recites: “The formulation of claim 1, wherein said sur-
    factant is a nonionic surfactant.”
    Id. col. 38 ll.
    6–7 (empha-
    sis added). Dependent claim 7’s recitation of a formulation
    with only a surfactant lends credence to Bracco’s argument
    that the backslash can mean “or” and not necessarily “and.”
    We next turn to the specification. Maia argues that
    this specification requires a construction of the backslash
    to mean only “and.”             However, Maia’s argument is
    grounded solely on this specification’s ambiguous language
    and its disclosure of a few preferred embodiments of the
    patent that include sincalide formulations comprising sur-
    factants. For example, Maia argues that the specification
    sets forth a pattern of using a backslash when describing
    multiple functions performed by the same excipient, as ex-
    emplified by Table 1. However, as Bracco points out, the
    backslash in Table 1 can also be interpreted to mean “or.”
    Additionally, all of Maia’s quotes from the specification ref-
    erence a preferred embodiment. Appellant Br. at 35–36
    (quoting ’046 patent col 1 ll. 56–62 (“In one aspect, the in-
    vention features sincalide formulations that include . . . a
    surfactant . . . .”), col. 2 ll. 1–2 (“In various embodiments of
    Case: 20-1387    Document: 54      Page: 18    Filed: 12/17/2020
    18   BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.
    the invention, the surfactant is a nonionic surfactant . . .
    .”)) (emphases added). Maia omits that the specification’s
    disclosure that “[t]he sincalide formulations of the inven-
    tion can include a variety of excipients, such as, for[] exam-
    ple . . . surfactants,” indicates that surfactants are not
    necessary. ’046 patent col. 4 ll. 8–12 (emphases added).
    Here, although the specification discloses a few preferred
    embodiments of sincalide formulations with surfactants,
    Maia has not demonstrated that the patentee has a “clear
    intention to limit the claim scope.” Hill-Rom Servs., Inc. v.
    Stryker Corp., 
    755 F.3d 1367
    , 1372 (Fed. Cir. 2014).
    We thus conclude that the district court correctly con-
    strued the backslash in surfactant/solubilizer to mean
    “and” or “or.”
    III. Surfactant
    Lastly, Maia argues that the district court erred in con-
    struing the term surfactant to mean “an excipient that may
    reduce the interfacial tension.” Maia asserts that in con-
    struing surfactant, the court improperly imported into the
    definition ambiguous and non-definitional language from
    the specification—“[t]he addition of a nonionic surfactant.
    . . may reduce the interfacial tension.” See ’046 patent col.
    11 ll. 27–34 (emphasis added). Maia argues that because
    every excipient “may” or “may not” reduce interfacial ten-
    sion, under the court’s construction, a surfactant encom-
    passes “every excipient in the universe,” including
    excipients that increase interfacial tension or are nonfunc-
    tional. Appellant Br. at 20. Maia argues that as a result,
    the court’s construction is contrary to the plain and ordi-
    nary meaning of the term.
    According to Maia, the plain and ordinary meaning of
    surfactant in view of the specification as a whole is a com-
    pound that “must” reduce the interfacial tension at the
    air/liquid or liquid/solid interfaces. Appellant Rep. Br. at
    18. As support for Maia’s narrower construction, it states
    that the only disclosed surfactant effect in the specification
    Case: 20-1387     Document: 54      Page: 19    Filed: 12/17/2020
    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.      19
    is the reduction of interfacial tension at the air/liquid or
    liquid/solid interface rather than any increase in interfa-
    cial tension. Maia points to the specification’s disclosure
    that a nonionic surfactant may “reduce the interfacial ten-
    sion . . . at air/liquid or liquid/solid interfaces . . . .” See
    ’046 patent col. 11 ll. 27–34. (emphases added). Maia also
    points to Example 3 of the patent, entitled “Effect of Sur-
    factants on Sincalide Formulations,” to support its argu-
    ment. Example 3 states, in relevant part, that use of even
    trace amounts of a surfactant “still produced a significant
    effect on the air/liquid interface.” ’046 patent col. 22 ll. 28–
    30 (emphases added). Maia states that the “effect” refers
    to an increase in potency attributed to the surfactant’s re-
    duction of surface tension at the air/liquid interface. Maia
    further cites several dictionaries that define surfactant to
    mean an excipient that necessarily reduces interfacial ten-
    sion at the air/liquid or liquid/solid interface.
    Bracco responds that the district court’s construction is
    accurate in light of the specification’s explicit disclosure
    that a surfactant “may reduce the interfacial tension.”
    Bracco disagrees with Maia’s position that the court’s use
    of “may” in the definition renders the term meaningless.
    According to Bracco, a person of skill would interpret “may”
    to mean “capable of under certain circumstances.” Appel-
    lee Br. at 14. As support, Bracco cites expert testimony.
    Thus, Bracco argues that the court’s construction would in-
    clude only surfactants that can, or are capable of, reducing
    interfacial tension, but would not include “everything in
    the universe.”
    Id. at 13.
         Bracco also argues that Maia is improperly loading ad-
    ditional limitations onto the term from the specification by
    requiring that surfactant be construed as an excipient that
    must reduce interfacial tension at certain interfaces.
    Bracco contends that the patentee has made no clear and
    unmistakable disclaimer that the definition of surfactant
    should be limited in the manner that Maia proposes. With
    regard to Maia’s argument that the specification discloses
    Case: 20-1387     Document: 54       Page: 20     Filed: 12/17/2020
    20   BRACCO DIAGNOSTICS INC.     v. MAIA PHARMACEUTICALS, INC.
    several statements and examples that surfactants reduce
    interfacial tension at the air/liquid or liquid/solid interface,
    Bracco responds that language referring to one preferred
    embodiment of a surfactant, does not so limit all surfac-
    tants.
    Id. at 39
    (“[T]he addition of a nonionic surfactant,
    such as polysorbate, to the formulation, may reduce the in-
    terfacial tension . . . at air/liquid or liquid/solid interfaces.”
    (quoting ’046 patent col. 11 ll. 29–34)) (emphasis added).
    Bracco further contends that Maia misrepresents Ex-
    ample 3 as supporting its argument that the only surfac-
    tant effect disclosed in the patent is reduction of interfacial
    tension. According to Bracco, Maia purports to quote from
    Example 3’s disclosure that a nonionic surfactant “still pro-
    duced a significant effect on the air/liquid interface,” and
    misleadingly ascribes that “effect” to increase in potency
    resulting from a surfactant’s reduction of interfacial ten-
    sion, while cropping the next line, which actually explains
    that the effect was the elimination of “foaming in the for-
    mulation.” ’046 patent col. 22 ll. 28–31. Bracco addition-
    ally asserts that Maia’s requirement that surfactants
    function at the air/liquid or liquid/solid interface does not
    comport with claim 40, which is directed to a powder mix-
    ture kit that has no liquid present.
    With regard to the extrinsic evidence proffered by
    Maia, Bracco asserts that a person of ordinary skill, which
    Bracco contends is a peptide drug formulator, would not
    look to dictionaries to learn about the formulation of a pep-
    tide drug; according to Bracco, formulation of peptide drugs
    presents highly specialized technical issues and a diction-
    ary would not be of use to a skilled peptide formulator.
    Bracco points out that several of Maia’s dictionaries reject
    Maia’s narrow construction of “surfactant” in favor of de-
    fining it as “usually” effecting other properties and other
    interfaces. J.A. 587. Lastly, Bracco asserts that Maia’s
    construction does not take into account evidence that a per-
    son of skill would consider a surfactant to have other effects
    Case: 20-1387    Document: 54      Page: 21     Filed: 12/17/2020
    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.     21
    including inhibition in aggregation, improvement in solu-
    bility, and reduction of adsorption.
    We agree with Bracco that the district court correctly
    construed the term surfactant. First, contrary to Maia’s
    assertion, the court’s use of the word “may” in its construc-
    tion does not render surfactant meaningless. We agree
    with Maia that “may,” standing alone, presents some am-
    biguity. However, the plain and ordinary meaning of “may”
    within the context of this specification is properly under-
    stood as indicating an inherent measure of likelihood or
    possibility. It is not used by a person of skill to describe an
    event that has no likelihood of occurring. For example, the
    specification discloses that “[t]he addition of a nonionic sur-
    factant . . . may reduce the interfacial tension” and contin-
    ues to provide an exemplary list of surfactants/solubilizers.
    ’046 patent col. 11 ll. 26–63 (emphasis added). It is unlikely
    that the patentee intended to provide an exemplary list of
    surfactants/solubilizers that could never be capable of re-
    ducing interfacial tension. Even Maia acknowledges that
    “may” encompasses possibility or probability in its brief.
    Appellant Br. at 19 (“It is undisputed that the term ‘may’
    is permissive, used to indicate possibility.”). It follows that
    the district court’s definition includes excipients that re-
    duce interfacial tension, or are capable of reducing interfa-
    cial tension, but excludes excipients that can never reduce
    interfacial tension. Thus, the term is not meaningless, as
    Maia alleges.
    We further disagree with Maia’s argument that the
    specification expressly indicates that surfactants must re-
    duce interfacial tension at the air/liquid or liquid/solid in-
    terface. First, the specification’s disclosure that one type
    of surfactant “may reduce the interfacial tension,” supports
    the district court’s construction that surfactants need not
    necessarily reduce interfacial tension. ’046 patent col. 11
    ll. 29–34 (emphasis added). Maia recites a few lines from
    the description section and from a preferred embodiment
    as support for its limitation. However, none of Maia’s
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    22   BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.
    references indicates that the patentee intended to limit the
    claim scope in the manner that it asserts. For example,
    Maia argues that Example 3 demonstrates that the pur-
    pose of surfactants is to increase potency through reduction
    of interfacial tension, although Bracco rightly points out
    that the “effect” could be referring to foaming.
    Id. col. 22 ll.
    28–31. We have repeatedly “cautioned against limiting
    the claimed invention to preferred embodiments or specific
    examples in the specification,” where, like here, the pa-
    tentee has not made a clear disavowal of the claim scope.
    Imaginal Systematic, LLC v. Leggett & Platt, Inc., 
    805 F.3d 1102
    , 1109–10 (Fed. Cir. 2015) (quoting Williamson v. Cit-
    rix Online, LLC, 
    792 F.3d 1339
    , 1346–47 (Fed. Cir. 2015));
    see also Ericsson, Inc. v. D-Link Sys. Inc., 
    773 F.3d 1201
    ,
    1218 (Fed. Cir. 2014) (“[I]t is important that we avoid im-
    porting limitations from the specification into the claims.”)
    (internal quotation marks omitted).
    Moreover, the district court’s construction is supported
    by the extrinsic evidence. In construing surfactant, the
    court relied on Dr. Forrest’s testimony that a peptide for-
    mulator in 2002 was aware that surfactants usually, but
    not necessarily, reduce interfacial tension. The court found
    his testimony “more thorough and reli[ant] upon a more
    authoritative list of sources” than Maia’s expert, Dr.
    Klibanov, who asserted that surfactants must reduce inter-
    facial tension at certain interfaces. Claim Construction Or-
    der, 
    2019 WL 4885888
    , at *8. We do not see, nor does Maia
    allege, any clear error in the court’s reliance on Dr. For-
    rest’s testimony over Dr. Klibanov’s testimony.
    CONCLUSION
    We have considered the parties’ remaining arguments
    but find them unpersuasive. For the foregoing reasons, we
    conclude that while the district court technically erred in
    construing the terms buffer, surfactant/solubilizer, and
    surfactant, its construction is essentially correct. We
    therefore affirm the judgment of infringement.
    Case: 20-1387   Document: 54      Page: 23    Filed: 12/17/2020
    BRACCO DIAGNOSTICS INC.   v. MAIA PHARMACEUTICALS, INC.   23
    AFFIRMED