NOTE: This disposition is nonprecedential.

United States Court of Appeals 

for the Federal Circuit ______________________

PAR PHARMACEUTICAL, INC., PAR STERILE 

PRODUCTS, LLC, ENDO PAR INNOVATION 

COMPANY, LLC,

Plaintiffs-Appellees

v.

HOSPIRA, INC.,

Defendant-Appellant

______________________

2020-1273

______________________

Appeal from the United States District Court for the 

District of Delaware in No. 1:17-cv-00944-JFB-SRF, Senior 

Judge Joseph F. Bataillon.

______________________

Decided: November 23, 2020

______________________

DANIEL BROWN, Latham & Watkins LLP, New York, 

NY, argued for plaintiffs-appellees. Also represented by 

JENNIFER KOH, San Diego, CA; GABRIEL BELL, Washington, 

DC. 

 THOMAS J. MELORO, Willkie Farr & Gallagher LLP, 

New York, NY, argued for defendant-appellant. Also 

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2 PAR PHARMACEUTICAL, INC. v. HOSPIRA, INC.

represented by DEVON WESLEY EDWARDS, MATTHEW S.

FREIMUTH. 

 ______________________

Before DYK, TARANTO, and STOLL, Circuit Judges.

TARANTO, Circuit Judge.

The plaintiffs (collectively, Par) own and have exclusive rights to U.S. Patent Nos. 9,119,876 and 9,295,657, 

which claim particular compositions containing epinephrine, the active ingredient in Par’s Adrenalin® products, as 

well as methods of administering such compositions to patients. In 2017, Hospira, Inc. filed an Abbreviated New 

Drug Application (ANDA) with the Food and Drug Administration, seeking permission to manufacture and market a 

generic version of Par’s Adrenalin® epinephrine injection, 

1 mg/mL, product. Par sued Hospira for patent infringement under 35 U.S.C. § 271(e), alleging that the ANDA was 

for a product, and use of a product, claimed in the ’876 and 

’657 patents. As relevant on appeal, Hospira responded by 

disputing infringement on the ground that its ANDA product would not meet several limitations of the asserted 

claims. After a bench trial, the district court ruled for Par 

and against Hospira, finding that Hospira’s ANDA was for 

a product that meets the disputed claim limitations. Par 

Pharm., Inc. v. Hospira, Inc., 420 F. Supp. 3d 256 (D. Del. 

2019) (Par). Hospira appeals the infringement determination. We affirm.

I

A

The ’876 and ’657 patents share a specification. The 

patents describe a “pharmaceutical composition comprising epinephrine,” which is used for “emergency treatment 

of allergic reactions.” ’876 patent, col. 2, lines 57–59. Par’s 

product, Adrenalin®, is an example of such a composition. 

Id., col. 1, lines 30–39. Previous formulations of 

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epinephrine, the patent states, tended to have short shelf 

lives because epinephrine degrades by three different 

mechanisms (oxidation, racemization, and sulfonation), 

and scientists found it difficult to control degradation by 

one mechanism without exacerbating degradation by another. Par, 420 F. Supp. 3d at 262; J.A. 240–41; J.A. 530–

38; ’876 patent, col. 1, lines 51–67. A predecessor company 

of Par eventually developed an improved formulation of 

Adrenalin® that met FDA standards for stability and quality, and Par secured the ’876 patent on the composition in 

September 2015, then the ’657 patent on use of the composition in March 2016. Par, 420 F. Supp. 3d at 262; J.A. 

4127–28.

The ’876 and ’657 patents each have only one independent claim. Claim 1 of the ’876 patent recites:

A composition comprising:

in the range of about 0.5 to 1.5 mg/mL 

of epinephrine and/or salts thereof,

in the range of about 6 to 8 mg/mL of 

a tonicity regulating agent,

in the range of about 2.8 to 3.8 mg/mL 

of a pH raising agent,

in the range of about 0.1 to 1.1 mg/mL 

of an antioxidant,

in the range of about 0.001 to 0.010 

mL/mL of a pH lowering agent, and

in the range of about 0.01 to 0.4 

mg/mL of a transition metal complexing agent,

wherein the antioxidant comprises sodium 

bisulfite and/or sodium metabisulfite.

’876 patent, col. 28, lines 2–14 (emphases added). Claim 1 

of the ’657 patent claims “a method of treating a condition” 

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by “administering” a composition with the same components and same concentration ranges as those identified in 

claim 1 of the ’876 patent. ’657 patent, col. 28, lines 28–47. 

Although additional limitations appear in claim 1 of the

’657 patent and in both patents’ other asserted claims (each 

dependent on its patent’s claim 1), the only limitations at 

issue in this court appear in claim 1 of the ’876 patent—

specifically, the limitations (emphasized above) that address (1) the tonicity regulating agent, (2) the transition 

metal complexing agent, and (3) the pH lowering agent.

Tonicity is the “effective osmotic pressure equivalent of 

a solution or composition.” ’876 patent, col. 8, lines 47–49. 

For living cells to maintain their physical integrity without 

shrinking or swelling, the osmotic pressure outside the cell 

must not exert too little (hypotonic) or too much (hypertonic) tension on the cells’ walls. J.A. 542–44. A tonicity 

regulating agent ensures that fluid injected into the blood 

remains isotonic, i.e., exerts the same pressure as human 

physiological fluid on the surrounding cells. J.A. 542–45.

A “transition metal complexing agent” reduces degradation of epinephrine through epinephrine’s binding to 

transition metals (e.g., copper and gold) in the formulation. 

Hospira identifies such transition metals as “elemental impurities.” Hospira Op. Br. 18 n.6 (“Elemental impurities 

include transition metals that may be present in the composition.”). Such a complexing agent can achieve that reduction by binding to the transition metals, making the 

bound molecules unavailable for binding to the epinephrine. J.A. 412–14. One type of transition metal complexing 

agent performing that function is a “chelating agent,” 

which is an agent that forms “two or more separate coordinate bonds” with metal ions. ’876 patent, col. 7, lines 11–

14.

A “pH lowering agent,” according to the parties’ agreedupon claim construction, is a “[c]omponent to lower the 

composition’s pH.” J.A. 76. Claim 1 requires not only a pH 

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lowering agent but also a pH raising agent, each within 

prescribed ranges. The patents state that “the pH raising 

agent” may include “a buffer system,” which itself “may 

comprise . . . more than one agent, such as a weak acid and 

its conjugate base,” i.e., a combination of a lowering agent 

(acid) and a raising agent (base). ’876 patent, col. 3, lines 

44–50; see also id., col. 8, lines 43–45 (“In certain embodiments, the pH lowering agent may be a portion of the buffer 

system in conjugation with a pH raising agent.”).

B

In June 2017, Hospira notified Par that it had submitted an ANDA to the FDA for approval to “manufacture, use, 

[sell], offer [to sell], and/or [import]” a generic version of 

Adrenalin®. J.A. 4129. On July 13, 2017, Par filed a complaint for patent infringement against Hospira in the District of Delaware under 35 U.S.C. § 271(e)(2), which 

provides that it is “an act of infringement to submit” an 

ANDA if the ANDA is “for a drug claimed in a patent or the 

use of which is claimed in a patent.” Par contended that 

Hospira’s ANDA was “for” a product that comes within 

claim 1 of the ’876 patent (and other claims of the ’876 patent dependent on claim 1) and whose use comes within 

claim 1 of the ’657 patent (and other claims of the ’657 patent dependent on claim 1). J.A. 4033. Hospira denied that 

infringement allegation. Par, 420 F. Supp. 3d at 260, 264.1

During discovery, the parties submitted agreed-upon 

claim constructions, including one for the term “about,”

which appears in all the numerical-range claim limitations 

at issue. J.A. 76. They agreed that “about” should be construed as having its “plain and ordinary meaning, i.e., approximately.” Id. In a pretrial order, the district court 

1 Hospira also asserted invalidity, but the district 

court rejected that assertion, Par, 420 F. Supp. 3d at 279–

80, and Hospira has not appealed that ruling. 

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stated that “[t]he extent of the term ‘about’ must be determined using a functional approach because ‘it is impossible 

to “capture the essence” of the claimed invention in strict 

numeric terms.’” Par Pharm., Inc. v. Hospira, Inc., No. 

1:17-cv-944, 2019 WL 2571165, at *2 (D. Del. June 21, 

2019) (quoting Cohesive Techs., Inc. v. Waters Corp., 543 

F.3d 1351, 1369–71 (Fed. Cir. 2008)). The court added that 

the proper scope of the concentration range encompassed 

by “about” “requires a factual inquiry as to the purpose of 

the limitation.” Id.

We summarize the key trial evidence regarding literal 

infringement. Given our affirmance of the finding of literal 

infringement, we omit mention of the evidence regarding 

infringement under the doctrine of equivalents. 

Regarding tonicity, Par’s expert, Dr. Elder, testified at 

trial that “about 6 to 8 mg/mL of a tonicity regulating 

agent,” as construed, would be understood in light of the 

stated purpose of the tonicity regulating agent—to maintain the integrity of living cells following the injection of 

epinephrine into the bloodstream. J.A. 158; see also ’876 

patent, col. 8, lines 46–53 (explaining that the tonicity regulating agent’s purpose is to “maintain the tonicity of the 

composition in a physiological acceptable range”). He 

noted that sodium chloride is “the prefer[red] . . . tonicity 

regulating agent,” ’876 patent, col. 8, lines 58–59, and that 

Hospira’s ANDA identifies sodium chloride in its product 

as included for “isotonicity,” J.A. 1290. See J.A. 152, 158. 

He also noted that the ANDA identifies 9 mg/mL of sodium 

chloride as a component of the covered composition, J.A. 

1290, and that Hospira’s test batches contained sodium 

chloride in amounts as low as 8.55 mg/mL, See J.A. 152–

53. Dr. Elder opined, on those facts, that Hospira’s ANDA 

product would fall within the contemplated “physiologically acceptable” range and therefore literally infringe the 

claim limitation. J.A. 152–53, 155–58. 

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Dr. Pinal, Hospira’s expert, did not dispute the facts 

about the role of sodium chloride or the amounts covered 

by Hospira’s ANDA. Rather, he disagreed with Dr. Elder 

about whether the amounts came within the claimed 

“about” range. He opined that a relevant artisan would understand “about” to encompass only slight deviations from 

a specific target concentration, e.g., due to measurement 

errors, and not to embrace the amounts covered by Hospira’s ANDA. J.A. 553–56.

Regarding the transition metal complexing agent claim

limitation, the evidence showed that Hospira’s ANDA specifies a particular concentration of citric acid, a known chelating agent, J.A. 1290, and also states that the ANDA 

product’s “elemental impurities” (which include transition 

metals, as noted supra) satisfy the requirements of the International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for 

Humane Use (ICH) Q3D guidelines, J.A. 1043; ICH Guidelines, J.A. 2485. The referred-to ICH Q3D guidelines specify that (to avoid the need for additional controls) elemental 

impurities in drug products be less than 30% of the specified permitted daily exposure (PDE). J.A. 2496–97. In the

table it presented to the FDA, Hospira represented that 

“[d]rug product testing is not required” because

“[e]lemental impurity levels for potential elements tested 

were found to be consistently less than 30% of the . . . 

PDE.” J.A. 1043 (cleaned up). Par’s expert, Dr. Toste, explained that using the upper limit of potential metals for 

his calculations was appropriate “[b]ecause the ANDA says 

[Hospira] could have up to that amount [of transition metals] and still be able to sell [its product].” J.A. 483. Using 

the 30% figure, Dr. Toste calculated the amount of citric 

acid that would act as a transition metal complexing agent 

for that level of transition metals—an amount that comes 

within the claimed range of 0.01 to 0.4 mg/mL. J.A. 426–

35. 

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Hospira’s expert, Dr. Gokel, admitted that the ANDA 

product includes a specified concentration of citric acid, see 

J.A. 1290, and that citric acid has known chelating properties, allowing it to complex with transition metals. J.A. 

741, 754–55. Dr. Gokel did not disagree with Dr. Toste’s 

calculation of the amount of citric acid serving as a transition metal complexing agent if one used the 30% level for 

the calculation. But Dr. Gokel rejected the use of the upper 

limit of the ICH guidelines to calculate the amount of transition metal complexing agent in the ANDA product, testifying that the proper concentration of transition metals 

should be the amounts measured in test batches of Hospira’s product. J.A. 763–65. Using the test batches, Dr. 

Gokel opined that the amount of citric acid that would 

serve as a transition metal complexing agent in the ANDA 

product would be far below the “about 0.01 to 0.4 mg/mL” 

claimed in Par’s patents. J.A. 766.

Regarding the claim requirement of “about 0.001 to 

0.010 mL/mL of a pH lowering agent,” the trial evidence 

established that Hospira’s ANDA covered a product containing a buffer system of citric acid and its conjugate base, 

sodium citrate, which together are considered the pH raising agent.2 J.A. 591. And it is undisputed that citric acid, 

being an acid, itself is a pH lowering agent. See, e.g., J.A. 

406–07, 409, 693. Par’s expert, Dr. Toste, identified the 

amount of citric acid covered by Hospira’s ANDA, subtracted the amount that could serve as a complexing agent 

2 The parties’ agreed-upon claim constructions state

that “pH raising agent” means a “[c]omponent to raise the 

composition’s pH, which may comprise a buffer system,” 

and a “buffer system” is a “[c]omponent present in a composition or solution, which may provide a resistance to significant change in pH caused by a strong acid or base; may 

comprise a single agent or more than one agent, such as a 

weak acid and its conjugate base.” J.A. 76.

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with transition metals, then concluded that the remaining 

citric acid would come within the claimed range for a pH 

lowering agent—even while those same citric-acid molecules would be part of the buffer system (citric acid combined with sodium citrate) that would serve as a pH raising 

agent. J.A. 449–53.

Dr. Pinal, testifying for Hospira, disagreed with counting the non-metal-complexing molecules of citric acid both 

as a pH lowering agent and as part of the pH raising agent. 

On that basis, he viewed only the hydrochloric acid in Hospira’s ANDA product as a pH lowering agent. J.A. 590–91. 

It is undisputed that the hydrochloric acid in the ANDA 

product is below the low end of the range stated in the pHlowering-agent claim limitation. Accordingly, Dr. Pinal 

opined, that limitation is not met. Id.

The district court resolved the foregoing issues in Par’s 

favor. First, the court determined that the sodium chloride 

permitted by Hospira’s ANDA comes within the claim limitation requiring “about 6 to 8 mg/mL” of a tonicity regulating agent. Par, 420 F. Supp. 3d at 277–78. (The court 

added that, in the alternative, the limitation is met under 

the doctrine of equivalents. Id. at 278.) Second, the court

determined that the ANDA covered a product having citric 

acid that would serve as a transition metal complexing 

agent in an amount that comes within the claimed-required range. Id. Third, the court found that Hospira’s

ANDA covered a product having citric acid that served as 

a pH lowering agent in an amount that comes within the 

claim-required range. Id. at 277.

Hospira timely appealed. We have jurisdiction under 

28 U.S.C. § 1295(a)(1).

II

We review the district court’s conclusions of law de 

novo and its findings of fact for clear error. Fed. R. Civ. P. 

52(a)(6); Vanda Pharm., Inc. v. West-Ward Pharm. 

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International Ltd., 887 F.3d 1117, 1123 (Fed. Cir. 2018). 

Infringement in this context, i.e., whether an ANDA is “for”

a patent-claimed drug or a patent-claimed use of a drug 

under 35 U.S.C. § 271(e)(2), is an issue of fact whose resolution by the district court is reviewed for clear error. 

Vanda, 887 F.3d at 1125.

On appeal, Hospira argues that the district court committed clear error in finding that its ANDA product contains: (1) “about 6 to 8 mg/mL of a tonicity regulating 

agent”; (2) “about 0.01 to 0.4 mg/mL of a transition metal 

complexing agent”; and (3) “about 0.001 to 0.010 mL/mL of 

a pH lowering agent.” We reject each argument.

A

Hospira first argues that its ANDA product would not 

come within the claim requirement of “about 6 to 8 mg/mL 

of a tonicity regulating agent” given that its ANDA specifies a target concentration of 9 mg/mL of sodium chloride. 

Hospira Op. Br. 34–50. The parties agreed in the district 

court that the term “about” had its “[p]lain and ordinary 

meaning; i.e., approximately.” J.A. 76. Hospira did not 

propose any further narrowing construction. On appeal,

Hospira contends that the district court, in applying the

plain-meaning construction to the ANDA, improperly departed from this court’s decision in Cohesive Techs. v. Water Corp., 543 F.3d 1351 (Fed. Cir. 2008), concerning an 

“about” term in a claim range. We disagree.

“When ‘about’ is used as part of a numeric range, ‘the 

use of the word “about” avoids a strict numerical boundary 

to the specified parameter.’” Cohesive, 543 F.3d at 1368 

(citing Pall Corp. v. Micron Separations, Inc., 66 F.3d 1211, 

1217 (Fed. Cir. 1995)). The authorized extension beyond 

the stated numbers in the range is cabined to what “a person having ordinary skill in the art . . . would reasonably 

consider ‘about . . .’ to encompass.” Monsanto Tech. LLC v. 

E.I. DuPont de Nemours & Co., 878 F.3d 1336, 1342 (Fed. 

Cir. 2018). Where, as here, there is no narrowing claim 

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construction proposed based on particular intrinsic-evidence statements or actions, the general considerations set 

forth in Cohesive govern. The extension effected by “about” 

must be tied to “the purpose of the limitation in the claimed 

invention—not the purpose of the invention itself.” Id. It 

also requires examination of whether the extension is by a 

“modest amount,” Conopco, Inc. v. May Dep’t Stores Co., 46 

F.3d 1556, 1562 (Fed. Cir. 1994), considering the “criticality of the [numerical limitation] to the invention,” Cohesive, 

543 F.3d at 1368 (quoting Ortho-McNeil Pharm., Inc. v. 

Caraco Pharm. Labs., Ltd., 476 F.3d 1321, 1327 (Fed. Cir. 

2007)) (alteration in original), as well as the “technologic 

and stylistic context” of the invention, Pall, 66 F.3d at 

1217. Thus, in Conopco, we concluded that the ordinary 

and customary meaning of “about” could not extend the upper bound of “‘about 40:1 to 1:1’” “as far as the prior art 

would allow” and could not reach as far as “162.9:1,” given 

the criticality of the ratio and that such an interpretation 

would result in an impermissible “expansion” of the term 

“about,” as opposed to a mere “stretch[]” by “a modest 

amount.” 46 F.3d at 1560–62.

Although defining the outer reaches of “about” in a 

claimed range can be a matter of claim construction, 

“[w]hen the claims are applied to an accused device, it is a 

question of technologic fact whether the accused device 

meets a reasonable meaning of ‘about’ in the particular circumstances.” Modine Manufacturing Co. v. U.S. Int’l 

Trade Comm’n, 75 F.3d 1545, 1554 (Fed. Cir. 1996), abrogated on other grounds by Festo Corp. v. Shoketsu Kinzoku 

Kogyo Kabushiki Co., 234 F.3d 558 (Fed. Cir. 2000), rev’d,

535 U.S. 722 (2002). 

The district court’s analysis is consistent with our precedents. The parties agreed that “about” should be construed to have its “plain and ordinary meaning” of 

“approximately,” J.A. 76, with no further refinement as a 

claim-construction matter. The district court therefore 

properly focused on whether Hospira’s ANDA product, 

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even the target 9 mg/mL sodium-chloride concentration,

would come within the “about” range as a matter of fact. 

See Par, 420 F. Supp. 3d at 277; see also Modine, 75 F.3d 

at 1549. And the court reasonably concluded that it would: 

based on the analytic framework of Cohesive, the evidence 

supported a finding that “about 8” encompasses 9, considering the purpose of the upper limit.

The court credited Dr. Elder’s testimony on this point,

Par, 420 F. Supp. 3d at 264–66, 277, which focused on the 

technological facts, the importance of the purpose of the 

limitation, and the limitation’s noncriticality. J.A. 155, 

158, 162–63. Dr. Elder explained the purpose of both ends 

of the claim range—to avoid hypertonicity of the solution 

(which would lead to cell shrinkage) and to avoid hypotonicity of the solution (which would lead to cell swelling) and 

thereby achieve isotonicity, which is the stated goal of Hospira’s inclusion of sodium chloride. J.A. 156–58. And he 

explained why it was clear that a “physiologically acceptable” concentration would include concentrations as high as 

9 mg/mL, there being nothing critical to the exact numbers 

in the claimed range given the purposes of the upper and 

lower limits. J.A. 160–61. The district court reasonably 

accepted this evidence, noting that Hospira’s Dr. Pinal “did 

not provide a meaningful analysis of the technologic context or the function of the claimed amount of tonicity regulating agent.” Par, 420 F. Supp. 3d at 277. We thus find 

no clear error with the district court’s finding, which “did 

not unduly interfere with the intended function of the 

claims, and did not eviscerate the plain meaning of the 

term ‘about.’” Conopco, 46 F.3d at 1562.

Hospira contends that, years after the ’876 and ’657 patent issued, Par made statements suggesting that 8.5 

mg/mL might be too high to be “about 6 to 8” in the course 

of prosecuting a continuation-in-part application that 

named a different inventor group, that had different 

claims, and that Par eventually abandoned. Hospira Op. 

Br. 41; J.A. 3958–59, 4008–09. We need not explore the 

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force that such statements might have had if Hospira had 

proposed a narrowing claim construction; Hospira did not 

do so. With the agreed-upon “plain and ordinary meaning” 

construction adopted, the remaining issue was what a relevant artisan would reasonably understand to come within 

“about 6 to 8 mg/mL” given the “modest amount” by which 

the range is expanded, Conopco, 46 F.3d at 1562, and the 

purposes and absence of criticality of the bounds of the 

range in the ’876 and ’657 patents. Hospira has cited no 

authority that would make Par’s later statements, made in 

a different context, controlling over the evidence that the 

district court relied on here to find in Par’s favor on this 

claim limitation.

B

Hospira next argues that the district court erred in accepting Par’s testimony that Hospira’s ANDA is for a product containing “about 0.01 to 0.4 mg/mL of a transition 

metal complexing agent.” Hospira’s argument is that the 

analysis should have focused entirely on the characteristics 

of the composition that Hospira was likely to sell, not on 

what compositions the ANDA, if approved, would allow 

Hospira to market. Hospira Op. Br. 51–60. We disagree.

As a threshold matter, the district court did not commit 

clear error in finding that citric acid acts as a transition 

metal complexing agent in Hospira’s ANDA product. See

Par, 420 F. Supp. 3d at 278. Hospira represented to the 

FDA that its citric acid buffer has a “chelating effect” allowing it to complex with transition metals. J.A. 4499. 

Hospira’s experts acknowledged at trial that citric acid has 

“chelating properties” and therefore could bind with elemental impurities in its product. J.A. 376, 754–55. It is 

not necessary that Hospira intended the citric acid to function as a chelating agent if, as the district court could readily find, the citric acid actually does so. Global-Tech 

Appliances, Inc. v. SEB S.A., 563 U.S. 754, 761 n.2 (2011) 

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(citing Aro Mfg. Co. v. Convertible Top Replacement Co., 

377 U.S. 476, 484 (1964)).

The infringement statute for ANDAs states that submission of an ANDA is “an act of infringement” if the 

ANDA is “for a drug claimed in a patent or the use of which 

is claimed in a patent.” 35 U.S.C. § 271(e)(2). Applying 

that language, we have held that “[w]hat a generic asks for 

and receives approval to market, if within the scope of a 

valid claim, is an infringement.” Sunovion Pharm., Inc. v. 

Teva Pharm., USA, Inc., 731 F.3d 1271, 1279 (Fed. Cir. 

2013); id. at 1278 (“[I]f a product that an ANDA applicant 

is asking the FDA to approve for sale falls within the scope 

of an issued patent, a judgment of infringement must necessarily ensue.”). Even where internal documents suggest 

that a generic product will not meet a claim limitation in 

practice, representations about the ANDA’s scope control 

the infringement analysis. Id. at 1279. That does not 

mean that the filing of an ANDA suffices to show that a 

generic product meets any claim limitation not excluded by 

the ANDA. Glaxo, Inc. v. Novopharm, Ltd., 110 F.3d 1562, 

1569–70 (Fed. Cir. 1997). When an ANDA is silent with 

respect to a claim limitation, Sunovion does not govern; it 

is the product that the generic company is likely to sell that 

guides the infringement analysis. Ferring B.V. v. Watson 

Labs., Inc.,-Fla., 764 F.3d 1382, 1387–88 (Fed. Cir. 2014). 

Here, we conclude, Sunovion governs. Hospira’s sole 

contention to the contrary is that the ANDA is silent about 

the presence of components that would establish whether 

the product meets the limitation requiring a defined 

amount of a transition metal complexing agent, i.e., 

whether the ANDA sets an upper limit on such an agent. 

We reject Hospira’s contention: Hospira’s ANDA is not silent on the point. Whether or not the ANDA identifies a 

lower limit on the amount of a component that would meet 

the limitation, a point about which Hospira does not present any separate argument, the ANDA does identify an 

upper limit bearing directly on the limitation at issue.

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It is not disputed before us that the amount of transition metal complexing agent is a simple function of the 

amount of elemental impurities in the form of transition 

metals in the composition. The ANDA states in a line entry 

in a table that its product satisfies the ICH Q3D guidelines, 

meaning that it can market and sell a product with up to 

30% of the permitted daily exposure of transition metal impurities. J.A. 1043. That line entry was added by Hospira 

in response to an FDA request for “adequate information” 

showing that its ANDA product would comply with ICH 

Q3D. J.A. 4528 ¶ 8; see also J.A. 4545 (Hospira informed 

the FDA that its “specifications [were] updated” to demonstrate that its product met the required elemental impurity 

guidelines). These disclosures to the FDA are sufficient to 

support the district court’s finding that “there are clearly 

metals” in Hospira’s ANDA product and that the amount 

of transition metals can “vary,” as Hospira’s Dr. Gokel admitted, and is “not subject to control.” Par, 420 F. Supp. 3d 

at 278; J.A. 166–67.

Thus, unlike in Ferring, the ANDA is not silent as to 

whether Hospira’s product could contain sufficient concentrations of elemental impurities such that citric acid would 

complex with the transition metals in a high enough concentration to satisfy the limitation requiring “about 0.01 to 

0.4 mg/mL of a transition metal complexing agent.” See 

Ferring, 764 F.3d at 1387–88. Sunovion therefore applies. 

We reject Hospira’s challenge regarding this claim limitation.

C

Finally, Hospira argues that the trial court erred in 

finding—without sufficient analysis—that its ANDA covers a product containing “about 0.001 to 0.010 mL/mL of 

a pH lowering agent.” Specifically, Hospira argues that the 

trial court improperly accepted Par’s counting not just hydrochloric acid but also citric acid as a pH lowering agent. 

Hospira contends that citric acid—specifically, the citric 

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16 PAR PHARMACEUTICAL, INC. v. HOSPIRA, INC.

acid that remains after subtracting the amount that serves 

as a transition metal complexing agent—cannot be a pH 

lowering agent because it is already included in the buffer 

system that counts toward meeting the claim limitation requiring a certain amount of pH raising agent. Hospira Op. 

Br. 60–63. We disagree.

Hospira has not made and preserved a claim-construction argument that, in these patents, an acid, i.e., a pH lowering agent, cannot also be part of an agent that overall 

serves to raise pH. Indeed, the passages of the specification of the ’876 and ’657 patents that discuss a “buffer system” made up of an acid and a base, quoted supra, at least 

strongly suggest the opposite. Rather than disputing the 

suggestion, Hospira agreed to claim constructions based directly on the specification passages. See J.A. 76; note 2, 

supra. We therefore reject Hospira’s argument that citricacid molecules must be allocated between the pH raising 

agent limitation and the pH lower agent limitation. And 

with that argument rejected, there is no clear error in the 

district court’s finding that Hospira’s ANDA product would 

have a pH lowering agent (citric acid, after subtracting 

those molecules that bind to transition metals) in an 

amount that comes within the concentration range required by the claims. Par, 420 F. Supp. 3d at 270–71, 277–

78.

III

The district court’s judgment is affirmed.

Each party shall bear its own costs.

AFFIRMED

Case: 20-1273 Document: 44 Page: 16 Filed: 11/23/2020