Sigma-Tau Healthscience, Inc. v. United States , 838 F.3d 1272 ( 2016 )


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  •   United States Court of Appeals
    for the Federal Circuit
    ______________________
    SIGMA-TAU HEALTHSCIENCE, INC., AKA SIGMA-
    TAU HEALTHSCIENCE, LLC,
    Plaintiff-Appellant
    v.
    UNITED STATES,
    Defendant-Appellee
    ______________________
    2016-1125
    ______________________
    Appeal from the United States Court of International
    Trade in No. 1:11-cv-00093-GWC, Judge Gregory W.
    Carman.
    ______________________
    Decided: September 26, 2016
    ______________________
    JOHN C. MONICA, JR., Porter Wright Morris & Arthur,
    Washington, DC, argued for plaintiff-appellant. Also
    represented by LESLIE ALAN GLICK, CHRISTOPHER YOOK.
    ALEXANDER J. VANDERWEIDE, Commercial Litigation
    Branch, Civil Division, United States Department of
    Justice, New York, NY, argued for defendant-appellee.
    Also represented by AMY M. RUBIN; BENJAMIN C. MIZER,
    JEANNE E. DAVIDSON, Washington, DC; YELENA SLEPAK,
    Office of Assistant Chief Counsel, U.S. Customs and
    2                     SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    Border Protection, United States Department of Home-
    land Security, New York, NY.
    ______________________
    Before NEWMAN, DYK, and REYNA, Circuit Judges.
    DYK, Circuit Judge.
    This Customs case concerns the classification of two
    chemical products, both stabilized forms of the compound
    carnitine, which were imported into the United States by
    Sigma-Tau HealthScience, Inc., a.k.a. Sigma-Tau
    HealthScience, LLC (“Sigma-Tau”). United States Cus-
    toms and Border Protection (“Customs” or “the govern-
    ment”) initially classified these products under a
    subheading of the Harmonized Tariff Schedule of the
    United States (“HTSUS”) that carries a duty. Sigma-Tau
    protested, arguing that the products should be classified
    under HTSUS heading 2936 (which encompasses “provit-
    amins and vitamins”), subheading 2936.29.50, a duty-free
    classification.
    The Court of International Trade (“CIT”) concluded
    that Sigma-Tau’s products should be classified under a
    different subheading, 2923.90.00, making them ineligible
    for duty-free treatment. Sigma-Tau HealthScience, Inc. v.
    United States (“Sigma-Tau”), 
    98 F. Supp. 3d 1365
    , 1377–
    78 (Ct. Int’l Trade 2015). On appeal, the parties agree
    that the only issue is whether Sigma-Tau’s products are
    properly classified as vitamins under HTSUS heading
    2936. We agree with Sigma-Tau that its carnitine prod-
    ucts are properly classified under that heading, because
    carnitine is a vitamin in neonates. We therefore reverse
    and remand.
    BACKGROUND
    Customs classifications according to the headings and
    subheadings of the HTSUS determine the duties that
    importers must pay to the United States. The question
    SIGMA-TAU HEALTHSCIENCE, INC.   v. US                     3
    here is the appropriate classification of Sigma-Tau’s
    carnitine products.
    Carnitine 1 is a naturally occurring amino acid deriva-
    tive and an important nutrient in the human body, where
    it serves to transport long-chain fatty acids into mito-
    chondria, the centers for energy production within each
    cell. Our bodies obtain carnitine exogenously, from food,
    and also produce it endogenously, by breaking down and
    reforming protein. (According to the Webster Comprehen-
    sive Dictionary, an “exogenous” compound originates
    outside the organism, while an “endogenous” compound is
    one originating or produced internally. See Exogenous,
    Webster Comprehensive Dictionary (Int’l ed. 2001); Endog-
    enous, id.) Stabilized forms of carnitine are formulated
    into tablets or capsules and sold as nutritional supple-
    ments; they can also be incorporated into drinks, protein
    bars, and other products for human consumption. Car-
    nitine is sometimes referred to as “vitamin Bt”; for exam-
    ple, the online version of Merriam Webster’s Medical
    Dictionary identifies “vitamin Bt” as a synonym of “car-
    nitine.” J.A. 1279. While carnitine is an organic com-
    pound, it is not listed by name in any heading or
    subheading of HTSUS Chapter 29, which covers “Organic
    Chemicals.”
    Sigma-Tau imports carnitine products into the United
    States. The two carnitine products at issue are acetyl L-
    carnitine taurinate hydrochloride with 1.5% silica, which
    1    Carnitine is a chiral compound and exists in two
    distinct stereoisomeric forms: the biologically active L-
    carnitine enantiomer and the inactive D-carnitine enanti-
    omer.     Sigma-Tau’s products specifically contain L-
    carnitine, and the parties agree that L-carnitine is the
    biologically and commercially significant enantiomer at
    issue in this case. For simplicity, we refer hereinafter to
    L-carnitine simply as “carnitine.”
    4                      SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    Sigma-Tau sells under the brand name “L-Tauro,” and
    glycine propionyl L-carnitine hydrochloride USP with
    1.5% silica, which Sigma-Tau sells under the brand name
    “GlycoCarn.” These products, white powders manufac-
    tured in Italy, were imported in bulk. In 2010, Customs
    classified these products under HTSUS subheading
    3824.90.92, which covers “Prepared binders for foundry
    molds or cores; chemical products and preparations of the
    chemical or allied industries (including those consisting of
    mixtures of natural products), not elsewhere specified or
    included: Other: Other: Other: Other.” That subheading
    carries a 5% duty. Sigma-Tau timely protested this
    classification, arguing that the products qualify as vita-
    mins under HTSUS subheading 2936.29.50, which covers
    “Provitamins and vitamins, natural or reproduced by
    synthesis (including natural concentrates), derivatives
    thereof used primarily as vitamins, and intermixtures of
    the foregoing, whether or not in any solvent: Vitamins
    and their derivatives, unmixed: Other vitamins and their
    derivatives: Other: Other.” That subheading is duty-free.
    Sigma-Tau brought suit in the CIT, requesting that
    the court set aside Customs’ classification decision and
    hold that the L-Tauro and GlycoCarn products are proper-
    ly classified as vitamins under HTSUS subheading
    2936.29.50 (and, therefore, deserving of duty-free treat-
    ment). Sigma-Tau also requested that the CIT instruct
    Customs to re-liquidate the entries for these products and
    to award damages for alleged overpayment of duties.
    Sigma-Tau moved for summary judgment. The govern-
    ment cross-moved for summary judgment, arguing that
    Customs’ initial classification of the merchandise under
    HTSUS heading 3824 was erroneous but that HTSUS
    subheading 2923.90.00 (covering “Quaternary ammonium
    salts and hydroxides; lecithins and other phosphoamino-
    lipids, whether or not chemically defined: Other”), not
    2936.29.50, was in fact the proper classification.
    SIGMA-TAU HEALTHSCIENCE, INC.   v. US                    5
    The CIT found that Sigma-Tau’s products were prima
    facie classifiable both as vitamins under HTSUS heading
    2936 and as quaternary ammonium salts under heading
    2923. 
    Sigma-Tau, 98 F. Supp. 3d at 1374
    –76. Where an
    item is prima facie classifiable under more than one
    heading, the General Rules of Interpretation provide
    guidance as to which heading should be used. See Dell
    Prods. LP v. United States, 
    642 F.3d 1055
    , 1057 (Fed. Cir.
    2011). Relying on HTSUS General Rule of Interpretation
    3 (“GRI 3”), which specifies that when “goods are, prima
    facie, classifiable under two or more headings” “[t]he
    heading which provides the most specific description shall
    be preferred to headings providing a more general de-
    scription,” HTSUS, General Notes, at 1, the CIT conclud-
    ed that “the term ‘quaternary ammonium salts’ more
    specifically describes L-Carnitine than ‘vitamins’” and
    thus that Sigma-Tau’s products were properly classified
    as quaternary ammonium salts under subheading
    2923.90.00, 
    Sigma-Tau, 98 F. Supp. 3d at 1377
    .
    The CIT consequently granted summary judgment in
    favor of the government and denied Sigma-Tau’s motion
    for summary judgment. 
    Id. at 1378.
    Sigma-Tau appeals,
    asking us to hold that the proper classification of its
    merchandise is under HTSUS subheading 2936.29.50, as
    a vitamin.     We have jurisdiction under 28 U.S.C.
    § 1295(a)(5).
    DISCUSSION
    “The interpretation of the headings and subheadings
    of the HTSUS is a question of law, which we review
    without deference.” Deckers Corp. v. United States, 
    532 F.3d 1312
    , 1314 (Fed. Cir. 2008); see also Airflow Tech.,
    Inc. v. United States, 
    524 F.3d 1287
    , 1290 (Fed. Cir.
    2008). “A classification decision involves two underlying
    steps: (1) determining the proper meaning of the tariff
    provisions, which is a question of law; and (2) determining
    which heading the particular merchandise falls within,
    6                      SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    which is a question of fact.” 
    Deckers, 532 F.3d at 1314
    –
    15. “We review questions of law de novo, including the
    interpretation of the terms of the HTSUS, whereas factu-
    al findings of the Court of International Trade are re-
    viewed for clear error.” 
    Id. at 1315;
    see also La Crosse
    Tech., Ltd. v. United States, 
    723 F.3d 1353
    , 1358 (Fed.
    Cir. 2013). However, “if there is no genuine dispute over
    the nature of the merchandise, . . . the proper classifica-
    tion under which it falls [is] the ultimate question in
    every classification case and one that has always been
    treated as a question of law.” Bausch & Lomb, Inc. v.
    United States, 
    148 F.3d 1363
    , 1366 (Fed. Cir. 1998); see
    also Gen. Elec. Co.-Med. Sys. Grp. v. United States, 
    247 F.3d 1231
    , 1235 (Fed. Cir. 2001).
    The government concedes that the CIT erred when it
    applied the rule of relative specificity of GRI 3 to classify
    Sigma-Tau’s products. The government acknowledges
    that Note 3 to Chapter 29 of the HTSUS (“Chapter Note
    3”) is instead applicable. Chapter Note 3 specifies that
    “[g]oods which could be included in two or more of the
    headings of this chapter are to be classified in that one of
    those headings which occurs last in numerical order.”
    HTSUS, Ch. 29, Note 3, at 29–1. We have held that “[t]he
    Section and Chapter Notes [of the HTSUS] are not op-
    tional interpretive rules, but are statutory law.” BenQ
    Am. Corp. v. United States, 
    646 F.3d 1371
    , 1376 (Fed. Cir.
    2011) (internal quotation marks omitted). Consequently,
    if Sigma-Tau’s merchandise is prima facie classifiable as
    both a quaternary ammonium salt (HTSUS heading 2923)
    and as a vitamin (HTSUS heading 2936), Chapter Note 3
    dictates that it be classified as the latter, as 2936 “occurs
    last in numerical order.”
    Thus, the only issue before us is whether Sigma-Tau’s
    L-Tauro and GlycoCarn products are prima facie classifi-
    able as vitamins under HTSUS heading 2936. If they are,
    that heading applies; if they are not, heading 2923 ap-
    SIGMA-TAU HEALTHSCIENCE, INC.    v. US                    7
    plies, as both sides agree that the products are prima
    facie classifiable as quaternary ammonium salts. 2
    I
    We first address the government’s contention that the
    products are not vitamins because they contain stabi-
    lizers. The two products at issue are stabilized forms of
    carnitine: acetyl L-carnitine taurinate hydrochloride with
    1.5% silica (L-Tauro) and glycine propionyl L-carnitine
    hydrochloride, USP with 1.5% silica (GlycoCarn). The
    CIT treated the products as equivalent to carnitine itself.
    At the CIT, the parties agreed that this was the correct
    approach. “The parties agree that the proper classifica-
    2     Before the CIT, Sigma-Tau argued that even if
    classified as quaternary ammonium salts under HTSUS
    heading 2923, its L-Tauro and GlycoCarn products should
    nonetheless qualify for “K designation” and thereby be
    granted duty-free treatment because “carnitine” is listed
    in the Pharmaceutical Appendix to the HTSUS. “General
    Note 13 [of the HTSUS] permits duty free treatment of
    certain pharmaceutical products if three requirements are
    met . . . .” Forest Labs., Inc. v. United States, 
    476 F.3d 877
    , 882 (Fed. Cir. 2007). One requirement of General
    Note 13 is that “the merchandise is listed in the Pharma-
    ceutical Appendix of the tariff schedule.” 
    Id. The CIT
    concluded that while carnitine itself is indeed
    listed in the Pharmaceutical Appendix, the taurine and
    glycine components of L-Tauro and GlycoCarn, respective-
    ly, are not listed, making L-Tauro and GlycoCarn ineligi-
    ble for K designation and thus ineligible for duty-free
    treatment under General Note 13. Sigma-Tau, 98 F.
    Supp. 3d at 1377. Sigma-Tau does not appeal this aspect
    of the CIT’s judgment. The inclusion of carnitine in the
    Pharmaceutical Appendix is unrelated to the question of
    whether carnitine is prima facie classifiable as a “vita-
    min” under HTSUS heading 2936.
    8                      SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    tion of the two products at issue hinges upon the primary
    and only active component of the products, L-Carnitine.”
    
    Sigma-Tau, 98 F. Supp. 3d at 1370
    . In its briefing at the
    CIT, the government described “L-carnitine (or carnitine)”
    as “the only biologically active component of the two
    products at issue” and indicated that the other chemical
    components serve merely as stabilizers, which “render the
    two carnitine-based products at issue chemically neutral
    and stable.” J.A. 336.
    On appeal, the government agrees that carnitine is
    “the sole biologically active component of L-Tauro and
    GlycoCarn” but now argues, apparently for the first time,
    that “the court erred when it undertook a classification
    analysis of L-Carnitine only, and not the actual products
    in their imported condition,” i.e., carnitine combined with
    stabilizing ingredients. Appellee’s Br. at 28. The gov-
    ernment does not articulate a theory as to how the pres-
    ence of any particular stabilizing component of L-Tauro or
    GlycoCarn (e.g., taurine, glycine, or silica) renders the
    products non-vitamins.
    The government’s argument comes too late and is
    therefore waived. “Our precedent generally counsels
    against entertaining arguments not presented to the
    district court.” Golden Bridge Tech., Inc. v. Nokia, Inc.,
    
    527 F.3d 1318
    , 1322 (Fed. Cir. 2008); see also Singleton v.
    Wulff, 
    428 U.S. 106
    , 120 (1976). Furthermore, even if the
    government had properly raised the argument, the
    HTSUS forecloses it. HTSUS heading 2936 explicitly
    encompasses “[p]rovitamins and vitamins” and “deriva-
    tives thereof used primarily as vitamins,” and Note 1(f) to
    Chapter 29 of the HTSUS expressly states that the head-
    ings of the chapter cover “[compounds] with an added
    stabilizer (including an anticaking agent) necessary for
    their preservation or transport.” HTSUS, Ch. 29, Note
    1(f), at 29–1.
    SIGMA-TAU HEALTHSCIENCE, INC.    v. US                   9
    We thus agree with the CIT that Sigma-Tau’s import-
    ed products, L-Tauro and GlycoCarn, should be viewed as
    equivalents of carnitine. The proper classification of
    carnitine itself determines the proper classification of
    Sigma-Tau’s merchandise.
    II
    Chapter 29 of the HTSUS covers “Organic Chemi-
    cals.” Heading 2936 more specifically covers “Provitamins
    and vitamins, natural or reproduced by synthesis (includ-
    ing natural concentrates), derivatives thereof used pri-
    marily as vitamins, and intermixtures of the foregoing,
    whether or not in any solvent.” The terms “carnitine” and
    “vitamin Bt” do not appear anywhere under heading 2936
    or, indeed, anywhere in Chapter 29. Thus, if carnitine is
    classifiable as a vitamin under heading 2936, it must be
    because it falls within a residual subheading, 2936.29.50
    (“Vitamins and their derivatives, unmixed: Other vita-
    mins and their derivatives: Other: Other”).
    The CIT construed HTSUS heading 2936 as, in rele-
    vant part, an eo nomine provision—i.e., a provision that
    describes an article by a specific name, not by use, see
    Len-Ron Mfg. Co., Inc. v. United States, 
    334 F.3d 1304
    ,
    1308 (Fed. Cir. 2003). 
    Sigma-Tau, 98 F. Supp. 3d at 1376
    –77. We agree with the CIT that HTSUS heading
    2936 should be treated as an eo nomine provision for
    purposes of this case: the operative question here is
    whether carnitine qualifies as a “[p]rovitamin[]” or “vita-
    min[],” items that are expressly named and covered by
    HTSUS heading 2936. 3 Neither party disputes this
    interpretation. Because we conclude that HTSUS head-
    3    HTSUS heading 2936 also encompasses “deriva-
    tives [of provitamins and vitamins] used primarily as
    vitamins”; this separate portion of heading 2936 is proper-
    ly read as a use provision.
    10                      SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    ing 2936 is an eo nomine provision with respect to “vita-
    mins,” we need not consider the Carborundum factors,
    which pertain only to certain use provisions of the
    HTSUS. See Aromont USA, Inc. v. United States, 
    671 F.3d 1310
    , 1312–13 (Fed. Cir. 2012); cf. GRK Canada,
    Ltd. v. United States, 
    761 F.3d 1354
    , 1358 (Fed. Cir.
    2014).
    “The first step in properly construing a tariff classifi-
    cation term is to determine whether Congress clearly
    defined that term in either the HTSUS or its legislative
    history.” Airflow 
    Tech., 524 F.3d at 1290
    –91 (quoting
    Russell Stadelman & Co. v. United States, 
    242 F.3d 1044
    ,
    1048 (Fed. Cir. 2001)). In this instance, there is no clear
    definition of “vitamin” within Chapter 29 or its legislative
    history. We have held that,
    [w]hen, as here, a tariff term is not defined in ei-
    ther the HTSUS or its legislative history, the
    term’s correct meaning is its common or diction-
    ary meaning in the absence of evidence to the con-
    trary. We have explained that, to determine the
    common meaning of a tariff term, a court may rely
    upon its own understanding of terms used, and
    may consult standard lexicographic and scientific
    authorities.
    
    Id. at 1291
    (citation, alterations, and internal quotation
    marks omitted). “To discern the common meaning of a
    tariff term, we may consult dictionaries, scientific author-
    ities, and other reliable information sources.” Kahrs Int’l,
    Inc. v. United States, 
    713 F.3d 640
    , 644 (Fed. Cir. 2013).
    To the extent that dictionaries or other extrinsic refer-
    ences disagree with one another, a court may “properly
    rel[y] on the definition most commonly found in the
    lexicographical sources to derive the common meaning of
    this term.” 
    Len-Ron, 334 F.3d at 1310
    .
    Here the CIT’s decision that carnitine is prima facie
    classifiable as a vitamin rested on the fact that carnitine
    SIGMA-TAU HEALTHSCIENCE, INC.   v. US                    11
    is alternatively known as “vitamin Bt.” “[T]he Court finds
    that since L-Carnitine is commonly known as vitamin Bt
    it is prima facie classifiable in HTSUS heading 2936.”
    
    Sigma-Tau, 98 F. Supp. 3d at 1376
    . Similarly, the gov-
    ernment argues in support of the opposite result that
    carnitine cannot be a vitamin because many respected
    scientific sources do not include carnitine in listings of
    commonly accepted vitamins. The government notes, for
    example, that a National Import Specialist for Customs
    testified with regard to Sigma-Tau’s carnitine products
    that “the FDA does not indicate they’re vitamins,” nor did
    the scientific literature he had reviewed. J.A. 750.
    Whether a substance is commonly referred to as a
    “vitamin” may be pertinent, but only if there is a consen-
    sus as to the use of that terminology. See 
    Len-Ron, 334 F.3d at 1310
    (holding that the common meaning of the
    HTSUS term “vanity case” should not be limited to cases
    that include mirrors, as the record showed that the public
    uses the term to refer to a variety of cases, with no con-
    sensus that the term “requires that the case be fitted with
    a mirror”); Nippon Kogaku (USA), Inc. v. United States,
    
    673 F.2d 380
    , 382, 384 (CCPA 1982) (holding that a
    certain type of optical microscope should be classified
    under a particular tariff heading because, inter alia, the
    CIT had found that “without contradiction, industry, as
    well as ophthalmologists and optometrists, principal users
    of the merchandise, refer to it as a slit-lamp microscope or
    a slit-lamp, not as a compound microscope”); see also
    CamelBak Prods., LLC v. United States, 
    649 F.3d 1361
    ,
    1368 (Fed. Cir. 2011) (holding that “how the subject
    articles are regarded in commerce” and “how the subject
    articles are described in sales and marketing literature”
    can “guide the court’s assessment of whether articles fall
    within the scope of an eo nomine provision”). There is no
    such consensus here. We must, therefore, determine
    whether carnitine is a “vitamin” under HTSUS heading
    12                    SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    2936, applying the commonly accepted definition of the
    term “vitamin.” 4
    Indeed, HTSUS heading 2936 contemplates such an
    inquiry. By its very terms the heading covers not only
    approximately one dozen expressly named vitamins 5 but
    also open-ended categories of further “Vitamins and their
    derivatives,” including “Other vitamins and their deriva-
    tives: Other: Aromatic or modified aromatic” (HTSUS
    subheading 2936.29.20) and “Other vitamins and their
    derivatives:    Other:   Other”     (HTSUS     subheading
    2936.29.50). While Explanatory Notes to HTSUS head-
    ings are non-binding (see infra), the Explanatory Note to
    heading 2936 states in its “List of products which are to
    be classified as provitamins or vitamins within the mean-
    4   This is not a case in which Customs or the im-
    porter contends that the term in question has a special
    commercial meaning distinct from its common meaning.
    See Carl Zeiss, Inc. v. United States, 
    195 F.3d 1375
    , 1379
    (Fed. Cir. 1999) (“One who argues that a tariff term
    should not be given its common or dictionary meaning
    must prove that it has a different commercial meaning
    that is definite, uniform, and general throughout the
    trade.”); see also Nix v. Hedden, 
    149 U.S. 304
    , 306 (1893)
    (“There being no evidence that the words ‘fruit’ and
    ‘vegetables’ have acquired any special meaning in trade or
    commerce, they must receive their ordinary meaning.”)
    5    The individual vitamins expressly included under
    HTSUS subheading 2936 are vitamin A (2936.21.00),
    vitamin B1 (2936.22.00), vitamin B2 (2936.23.00), D- or
    DL-pantothenic acid (vitamin B3 or vitamin B5,
    2936.24.00), vitamin B6 (2936.25.00), vitamin B12
    (2936.26.00), vitamin C (2936.27.00), vitamin E
    (2936.28.00), folic acid (2936.29.10), niacin and niacina-
    mide (2936.29.15), vitamin D (2936.29.50.20), and biotin
    (2936.29.50.30).
    SIGMA-TAU HEALTHSCIENCE, INC.   v. US                     13
    ing of heading 29.36” that “[t]he list of products in each of
    the following groups is not exhaustive” and that “[t]he
    products listed are examples only.” Explanatory Notes to
    the Harmonized Commodity Description and Coding
    System 29.36 (5th ed. 2012) (“EN 29.36”). Explanatory
    Note 29.36 also includes a list of “Exclusions,” products
    “which, though sometimes called vitamins, have no vita-
    min activity or have a vitamin activity which is of second-
    ary importance in relation to their other uses” and thus
    are not classifiable under HTSUS 2936. 
    Id. Among the
    excluded products are various compounds whose names
    include the word “vitamin,” such as “Vitamin H1,” “Vita-
    min B4,” and “Vitamin F.” 
    Id. (Carnitine (or
    vitamin Bt)
    is not included among the “Exclusions.” Id.) The note
    thus makes clear that the mere use of the term “vitamin”
    to refer to a particular compound is not conclusive. At the
    same time, the universe of compounds prima facie classi-
    fiable as vitamins under heading 2936 cannot be limited
    to only those compounds that are explicitly listed under
    the heading.
    We thus look to the definition of “vitamin” and ask
    whether carnitine falls within the definition. “Determin-
    ing the proper classification requires first construing the
    relevant provisions of the schedule and then deciding
    which provision encompasses the merchandise at issue.”
    Del Monte Corp. v. United States, 
    730 F.3d 1352
    , 1354
    (Fed. Cir. 2013); see also Airflow 
    Tech., 524 F.3d at 1291
    .
    Before the CIT, the government urged that the court
    apply the definition of “vitamin” in the Explanatory Note:
    Vitamins are active agents, usually of complex
    chemical composition, which are obtained from
    outside sources and are essential for the proper
    functioning of human or other animal organisms.
    They cannot be synthesised by the human body
    and must therefore be obtained in final or nearly
    final form (provitamins) from outside sources.
    They are effective in relatively minute amounts
    14                      SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    and may be regarded as exogenous biocatalysts,
    their absence or deficiency giving rise to metabolic
    disturbances or “deficiency diseases.”
    EN 29.36 (emphasis added). The government contended
    at the CIT that because carnitine can be synthesized in
    the human body, it is not a vitamin under the definition of
    EN 29.36. But Explanatory Notes are not Chapter Notes
    or Section Notes and are not binding. Explanatory Notes
    “may be generally useful as guides to the scope of unclear
    HTSUS headings, [but] they are not legally binding.”
    Archer Daniels Midland Co. v. United States, 
    561 F.3d 1308
    , 1315 (Fed. Cir. 2009) (internal quotation marks
    omitted); see also E.T. Horn Co. v. United States, 
    367 F.3d 1326
    , 1329 (Fed. Cir. 2004) (Explanatory Notes are “not
    controlling” but “provide interpretive guidance”). “Alt-
    hough the examples in the Explanatory Notes are proba-
    tive and sometimes illuminating, we shall not employ
    their limiting characteristics, to the extent there are any,
    to narrow the language of the classification heading
    itself.” Rubie’s Costume Co. v. United States, 
    337 F.3d 1350
    , 1359 (Fed. Cir. 2003).
    Explanatory Note 29.36, in defining vitamins as com-
    pounds that “cannot be synthesised by the human body,”
    cannot be correct, since vitamin D is unambiguously
    included under the heading: subheading 2936.29.50.20
    expressly names “Vitamins D and their derivatives.” And
    undisputed evidence establishes that vitamin D can be
    synthesized, in limited and generally inadequate
    amounts, by the human body. See Sigma-Tau, 98 F.
    Supp. 3d at 1375–76. This portion of the definition of
    “vitamin” in EN 29.36 thus contradicts the express inclu-
    sion of vitamin D under HTSUS heading 2936 and must
    be disregarded, as the CIT correctly held. 
    Id. at 1376.
    Explanatory Note 29.36 is also inconsistent with the
    prevailing definitions of “vitamin” in various scientific
    references cited by the parties, all of which define a
    vitamin as a compound that is not produced by the human
    SIGMA-TAU HEALTHSCIENCE, INC.   v. US                     15
    body in amounts “sufficient” or “adequate” for healthy
    function. 6 The parties indeed agree that the definition of
    6     The definitions of “vitamin” presented by the par-
    ties are as follows. Sigma-Tau’s expert submitted a report
    presenting definitions from two textbooks:
    (From The Vitamins:) A vitamin: (i) is an organic
    compound distinct from fats, carbohydrates, and
    proteins; (ii) is a natural component of foods in
    which it is usually present in minute amounts;
    (iii) is essential, usually in minute amounts, for
    normal physiological function (i.e., maintenance,
    growth,      development,     and/or    production);
    (iv) causes, by its absence or underutilization, a
    specific deficiency syndrome; and (v) is not synthe-
    sized by the host in amounts adequate to meet
    normal physiological needs.
    (From Nutrition Now:) Vitamins are chemical
    substances that perform specific functions in the
    body. They are essential nutrients because, in
    general, the body cannot produce them or [cannot]
    produce sufficient amounts of them.
    J.A. 288 (Expert Report of Yesu T. Das, quoting Gerald F.
    Combs, Jr., The Vitamins 4 (4th ed. 2012) (J.A. 291) and
    Judith E. Brown, Nutrition Now 20–2 (7th ed. 2014) (J.A.
    292)) (alteration and emphasis in original, underscoring
    added).
    The government introduced definitions from two
    chemical encyclopedias:
    Vitamins are specific organic compounds that are
    essential for normal metabolism. These micronu-
    trients are not synthesized by humans, either at all
    or in sufficient quantity, and must be obtained
    from the diet or as synthetic supplements.
    16                     SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    EN 29.36 is too restrictive in this respect. For example,
    the government proposes defining “vitamins” as “those
    organic compounds which are essential for human health,
    but must be provided or supplemented from an exogenous
    source because the human body cannot normally synthe-
    size the compounds, either sufficiently or at all.” Appel-
    lee’s Br. at 14 (emphasis added).           Moreover, the
    definitions provided by both parties are consistent with
    each other. We therefore adopt, as the definition of “vit-
    amin,” the following: vitamins are organic chemical
    substances that are essential micronutrients because, in
    general, the body cannot produce them or produce suffi-
    cient amounts of them.
    While agreeing to this general definition, the parties
    still differ as to the proper scope of this definition in
    certain respects. First, Sigma-Tau argues that “vitamin”
    should not be limited to compounds that are required by
    individuals with normal function but should also encom-
    pass those required by individuals with abnormal func-
    tion. We reject this argument. Literature definitions
    introduced by both parties emphasize the fact that a
    vitamin is a substance required for normal physiological
    J.A. 778 (reproducing the Concise Encyclopedia of Chem.
    Tech. 2092 (4th ed. 1999)) (emphasis added).
    Vitamins are essential, organic compounds which
    are either not synthesized in the human and ani-
    mal organism or formed only in insufficient
    amounts. Therefore, they must be regularly con-
    sumed with the diet either as such or as a precur-
    sor (provitamin) that can be converted to the
    vitamin in the body. . . . Vitamins are classified
    not chemically but by their activity.
    J.A. 780 (reproducing Ullmann’s Encyclopedia of Indus.
    Chemistry vol. 38, 112 (6th ed. 2003)) (emphasis added).
    SIGMA-TAU HEALTHSCIENCE, INC.   v. US                  17
    function. See J.A. 291 (The Vitamins: “essential . . . for
    normal physiological function”; “not synthesized by the
    host in amounts adequate to meet normal physiological
    needs” (emphasis added)); J.A. 292 (Nutrition Now: “es-
    sential nutrients because, in general, the body cannot
    produce them or produce sufficient amounts of them”
    (emphasis added)); J.A. 778 (Concise Encyclopedia of
    Chem. Tech.: “specific organic compounds that are essen-
    tial for normal metabolism” (emphasis added)). The
    correct definition of “vitamin” thus leaves out compounds
    that might be essential to individuals with abnormal
    physiological function, e.g., those suffering from rare
    genetic disorders or organ failure.
    Second, the government appears to argue that the
    proper definition of “vitamin” refers only to compounds
    that cannot be synthesized in sufficient amounts by
    human adults. On the contrary, Sigma-Tau argues that
    the proper definition of “vitamin” must not be limited to
    compounds essential to adults but should also include
    compounds that children and infants require for normal,
    healthy function. We agree with Sigma-Tau that there is
    no reason to limit “vitamin” to compounds required by
    adults rather than children. Neither the definition of EN
    29.36 nor any of the literature definitions presented by
    either party is expressly limited to adults. Moreover, the
    definition in The Vitamins describes “vitamins” as com-
    pounds “essential” for “maintenance, growth, develop-
    ment, and/or production,” J.A. 291 (emphasis added); the
    inclusion of “growth” and “development” suggests that
    compounds required by children—i.e., those who are
    “growing” and “developing”—should be included even if
    not required by adults.
    III
    Having defined “vitamin,” we turn to whether car-
    nitine is prima facie classifiable as such under HTSUS
    heading 2936. We hold, based on the undisputed evidence
    18                     SIGMA-TAU HEALTHSCIENCE, INC.   v. US
    of record, that the CIT’s conclusion on this point was
    correct: carnitine is prima facie classifiable as a vitamin.
    Sigma-Tau argues that the evidence shows that “cer-
    tain human populations, including children and neonates,
    require an exogenous source of L-Carnitine.” Appellant’s
    Reply Br. at 14. Sigma-Tau introduced uncontroverted
    evidence establishing that infants, including neonates
    (infants less than four weeks old), require exogenous
    sources of carnitine for healthy growth and cannot syn-
    thesize adequate quantities endogenously. One scientific
    article states that “[n]eonates rely on an exogenous supply
    of L-carnitine because their capacity for endogenous
    synthesis is still poorly developed.”        J.A. 1089 (J.
    Harmeyer, The Physiological Role of L-Carnitine, 27
    Lohmann Info. 1, 7 (2002)). A second article states that
    “certain pediatric populations, specifically neonates and
    infants, have decreased biosynthetic capacity and are at
    risk of developing carnitine deficiency, particularly when
    receiving PN [(parenteral nutrition)]” and that
    “[a]lthough carnitine is considered a nonessential nutrient
    in adults, it may be considered a conditionally essential
    nutrient in pediatric populations, particularly neonates
    receiving PN.” J.A. 1091, 1094 (Catherine M. Crill &
    Richard A. Helms, The Use of Carnitine in Pediatric
    Nutrition, 22 Nutrition in Clinical Practice 204, 207
    (2007)).
    The scientific authorities cited by the government do
    not directly address the question of whether carnitine
    qualifies as a vitamin with respect to infants. They
    merely state that carnitine is not recognized as a vitamin
    in adults, as adults are able to synthesize adequate quan-
    tities of carnitine from other components of their diet.
    For example, the book Recommended Dietary Allowances,
    a publication of the National Research Council introduced
    by the government, states that “[carnitine] has not been
    demonstrated to be a vitamin for the healthy adult hu-
    man” but adds that “the newborn infant appears to have
    SIGMA-TAU HEALTHSCIENCE, INC.   v. US                    19
    reduced stores of carnitine as well as a low capacity for
    synthesizing it” and that “[s]everal laboratories are inves-
    tigating the possibility that carnitine may be an essential
    nutrient for the newborn, especially for those born prema-
    turely.” J.A. 789, 790 (Recommended Dietary Allowances
    265, 266 (10th ed. 1989)). At argument the government
    conceded that the evidence shows that infants, and neo-
    nates in particular, require exogenous sources of carnitine
    for normal, healthy function.
    In view of this evidence, the CIT correctly held that
    carnitine is prima facie classifiable as a vitamin. Undis-
    puted evidence in the record shows that carnitine is an
    organic compound essential for neonates (infants less
    than four weeks old). They rely on an exogenous supply of
    L-carnitine because their ability to synthesize it endoge-
    nously is still poorly developed.
    CONCLUSION
    For the foregoing reasons, carnitine and Sigma-Tau’s
    imported merchandise are prima facie classifiable as a
    vitamin under HTSUS heading 2936. As noted above,
    under Chapter Note 3, “[g]oods which could be included in
    two or more of the headings of this chapter are to be
    classified in that one of those headings which occurs last
    in numerical order.” We thus hold that carnitine, and
    Sigma-Tau’s products, are properly classified as a vitamin
    under HTSUS heading 2936, in residual subheading
    2936.29.50, rather than as a quaternary ammonium salt
    under HTSUS heading 2923. We conclude that the CIT
    erred in denying Sigma-Tau’s motion for summary judg-
    ment and in granting summary judgment to the govern-
    ment. We reverse and remand for further proceedings
    consistent with this opinion.
    REVERSED AND REMANDED
    COSTS
    No costs.