UNITED STATES DISTRICT COURT

NORTHERN DISTRICT OF ILLINOIS

EASTERN DIVISION

CUMBERLAND PHARMACEUTICALS, INC., )

)

Plaintiff, )

)

v. ) No. 12 C 3846

)

MYLAN INSTITUTIONAL LLC, and MYLAN INC., ) Judge Rebecca R. Pallmeyer

)

Defendant. )

MEMORANDUM OPINION AND ORDER

Plaintiff Cumberland Pharmaceuticals, Inc. ("Cumberland") develops, manufactures and 

sells pharmaceutical products, including Acetadote, an intravenous treatment for suspected 

acetaminophen overdoses. Cumberland brought this patent infringement suit against 

Defendants Mylan Institutional, LLC and Mylan, Inc. (collectively "Mylan") for infringement of two 

patents related to Acetadote: United States Patents No. 8,148,356 and No. 8,399,445. 

Specifically, Cumberland charges Mylan with infringing these patents in violation of 35 U.S.C. § 

271(e)(2) by attempting to obtain FDA approval for a generic formulation of Acetadote. The 

parties have presented competing interpretations for three terms in the claims of the patents at 

issue. The court's construction of these terms follows.

BACKGROUND

I. The Patent

Acetaminophen overdose sends as many as 78,000 Americans to the emergency room 

each year. Jeff Gerth & T. Christian Miller, Use Only as Directed, ProPublica, Sept. 20, 2013, 

http://www.propublica.org/article/tylenol-mcneil-fda-use-only-as-directed (last visited Feb. 25, 

2014). Overdoses are so common, in part, because the over-the-counter pain reliever (best 

known under the brand name Tylenol) is also found in varying doses in several hundred 

common cold remedies and combination pain relievers. Acetaminophen poisoning can cause 

acute hepatic (i.e., liver) failure, severe brain damage, or even death. Id. Plaintiff Cumberland 
2

Pharmaceuticals, Inc. manufactures and sells Acetadote, an intravenous formulation of Nacetylcysteine1 ("NAC"), used to treat suspected acetaminophen overdoses in order to prevent 

or diminish hepatic injury. (Pl.'s Resp. Br. on Claim Construction [165], hereinafter "Pl.'s Resp.

Br." at 2.) At issue in this case are two patents Cumberland holds related to Acetadote: No. 

8,148,356 ("the '356 patent") and No. 8,399,445 ("the '445 patent"). The '356 patent, which 

issued on April 3, 2012, "relates to novel acetylcysteine compositions in solution, comprising 

acetylcysteine and which are substantially free of metal chelating agents, such as EDTA2

." U.S. 

Patent No. 8,148,356, hereinafter "'356 patent," abstract (filed Aug. 24, 2005) (issued April 3, 

2012). The '445 patent claims the methods of administering the compositions covered by the 

'356 patent. As the '445 patent is divisional of the '356 patent, the two share a common 

specification. 

Prior to the patents-in-suit, acetylcysteine was marketed worldwide generically as well as 

under several trade names as an inhalable mucolytic3 and as both an injectable and an oral 

agent to treat acetaminophen overdose. '356 patent, col. 1 ll. 26-36. In fact, Plaintiff's own 

previous version of Acetadote is one of the prior art products that contained acetylcysteine as 

 1 Cysteine is a sulfur-containing nonessential amino acid produced by the 

enzymatic or acid hydrolysis of proteins. The N-acetyl derivative of l-cysteine is used as a 

mucolytic agent for adjunct therapy in bronchopulmonary disorders to reduce the viscosity of 

mucus and facilitate its removal, administered by instillation or nebulization; and as an antidote 

for acetaminophen poisoning, administered orally or intravenously. Dorland's Medical Dictionary

14, 469 (31st ed. 2007).

2 Edetic (ethylenediaminetetraacetic) acid. Salts of EDTA are used as chelating 

agents for direct treatment of metal poisoning because they bind the toxic metal ions more 

strongly than do the vulnerable components of the living organism. Encyclopaedia Britannica 

Online Academic Edition, http://www.britannica.com/EBchecked/topic/108427/chelate?anchor=

ref49109 (last visited Jan. 6, 2014).

3 An agent "capable of reducing the viscosity of mucus." Dorland's Medical 

Dictionary 1204 (31st ed. 2007).
3

an active ingredient. (Id.) The earlier Acetadote formula was the same as the asserted claims 

here except that the earlier formula, like other acetaminophen overdose antidotes, contained 

chelating agents.

4

 (Def.'s Opening Claim Construction Br. [147], hereinafter "Defs.' Opening 

Br.," at 3.) It is the absence of chelating agents that is the key advancement of the invention, as 

chelators have "undesirable effects" including fatality and "reproductive developmental toxicity." 

'356 patent, col. 2 ll. 12–20.

II. The Disputed Claims

The '356 and '445 patents, titled "Acetylcysteine Composition and Uses Thereof," set 

forth fourteen and sixteen claims, respectively. The parties dispute three terms that appear 

throughout the patents' claims: (1) "acetylcysteine", (2) "free from a chelating agent"/"free of a 

chelating agent" (hereinafter "free of/from a chelating agent"), and (3) "stable aqueous 

pharmaceutical composition." The usage of these terms in the first claim of the '356 patent is 

exemplary (disputed terms emphasized below):

1. A stable aqueous pharmaceutical composition comprising between 

200 and 250 mg/mL acetylcysteine, wherein the composition is free from a 

chelating agent, or pharmaceutically acceptable salts thereof, wherein said 

composition is in a suitable form for intravenous injection, wherein the pH of the 

composition is from 6 to 7, and wherein said composition is sealed in an airtight 

container comprising a fill volume of said composition and a headspace volume 

occupied by a pharmaceutically inert gas.

'356 Patent. 

III. Prosecution History

Cumberland first sought Food and Drug Administration ("FDA") approval of Acetadote in 

June 2002, when it filed New Drug Application ("NDA") No. 21-539. (Id.) On January 23, 2004, 

 4 "Chelating agents, or chelators, are organic agents that bond with and thereby 

sequester free metal ions from solution. A widely used chelator is edetic acid or 

ethylenediaminetetraacetic acid, commonly referred to as EDTA[.]" '356 patent, col. 1 ll. 44-49.
4

the FDA approved Acetadote as an "orphan drug."

5 (Defs.' Opp'n to Mot. to Dismiss [45] at 2.) 

Because of this status, Cumberland enjoyed a seven-year period of exclusivity during which it 

faced no competition in the market. 21 U.S.C. § 360cc. On August 24, 2005, Cumberland filed 

patent application no. 11/209,804 (the "'804 patent application").6 The prosecution of that 

application, which resulted in issuance of the '356 patent, spanned nearly seven years. During 

that period, the Patent Office issued three separate final rejections to which Cumberland 

responded with several claim amendments and three applications for continued examination. 

(Defs.' Opening Br., Ex. C, at 304 (03/11/2008 Claim Amendments); 328 (05/28/2008 Final 

Rejection), 340 (08/12/2008 Request for Continued Examination with Claim Amendments), 436 

(12/03/2008 Claim Amendments), 451 (03/06/2009 Final Rejection), 460 (04/24/2009 Claim 

Amendments), 481 (05/27/2009 Request for Continued Examination with Claim Amendments), 

536 (11/25/2009 Claim Amendments), 563 (07/09/2010 Final Rejection), 616 (10/08/2010 Claim 

Amendments), 656 (10/21/2010 Request for continued Examination with Claim Amendments), 

664 (11/16/2010 Claim Amendments), 760 (07/22/2011 Claim Amendments), 875 (02/08/2012 

Examiner Claim Amendments.) By the time the '356 patent issued, several of the claims in the 

issued patent had been amended substantially from the initial application. 

Relevant to this suit, the phrase "free of/from a chelating agent" was the result of several 

iterations during the course of the '356 patent's prosecution. Claim 1 of the initial application 

read, "An aqueous pharmaceutical composition comprising acetylcysteine, wherein the 

composition is substantially free of EDTA or pharmaceutically acceptable salts thereof." (Id. at 

 5 Orphan drugs are products used to treat diseases or afflictions that are rare (i.e., 

affecting less than 200,000 people in the United States annually). See 21 U.S.C. §§ 

360bb(a)(1), 360cc(a).

6 Leo Pavliv ("Pavliv"), a senior executive at Cumberland, is the named inventor on 

the '804 patent application. For the purposes of this opinion, however, the court will refer to 

"Cumberland" for purposes of discussing both Plaintiff's and Mr. Pavliv's actions during 

prosecution.
5

70-74.) However, the phrase "substantially free of EDTA" was rejected as "indefinite" under 35 

U.S.C. § 112. (Id. at 292.) Cumberland responded to this rejection by deleting the offending

phrase, leaving the application as decribing a composition containing "less than 0.04% w/v 

EDTA," "less than 0.03% w/v EDTA," "less than 0.01% w/v EDTA," "less than 0.0025% w/v 

EDTA," or "no EDTA." (Id. at 341–55.) Later, Plaintiff again amended the claims by replacing 

"EDTA" in the above phrases with "a chelating agent." (Id. at 665.) At the same time, 

dependent claims were also added to reflect a limit on EDTA specifically. (E.g., id. at 665

(Claim 3: "The aqueous pharmaceutical composition of Claim 2, wherein the chelating agent is 

EDTA, and the composition contains less than 0.02% w/v EDTA"); (Claim 71: "The composition 

of Claim 64, wherein the chelating agent is EDTA."

7

) Finally, in February 2012, Examiner

Christopher Stone ("Examiner")—with Plaintiff's consent—replaced these weight-per-volume 

limitations with the phrase "is free from a chelating agent" and "is free of a chelating agent." (Id. 

at 875–76.) The claims of the '356 patent—issued on April 3, 2012—contain these phrases, 

while the phrase "substantially free of chelating agents" remains in the specification. 

Cumberland filed the application for the '445 patent on February 27, 2012. This patent, which 

was issued on March 19, 2013, claims methods for administering the compositions covered by 

the '356 patent. The '445 patent uses the phrase "free of chelating agents" and does not refer 

to EDTA or any other chelator in separate dependent claims. U.S. Patent No. 8,399,445, 

hereinafter "'445 patent," col. 9 ll. 21–22.

IV. This Lawsuit

In December 2011 (shortly before the '356 patent issued in April 2012), Mylan filed 

Abbreviated New Drug Application ("ANDA") No. 20-3624 seeking FDA approval of a generic 

version of Acetadote. (Defs.' Opp'n at 2.) Mylan subsequently provided the FDA with a 

 7 Claim 71, which became Claim 14 in the final version of the patent, is dependent 

on Claim 64, which became Claim 9. 
6

certification under 21 U.S.C. § 355(j)(2)(A)(vii) ("Paragraph IV certification") that its ANDA 

product does not infringe upon any valid claim of the '356 patent. (Defs.' Opp'n at 2.) Mylan 

also sent notice of the Paragraph IV certification to Cumberland. (Id.) Cumberland filed the 

instant suit for infringement on May 17, 2012, pursuant to the Hatch Waxman Act, 21 U.S.C. § 

355(j)(5)(B)(iii), alleging that Mylan's filing of its ANDA with a Paragraph IV certification 

constituted an act of infringement of the '356 patent under 35 U.S.C. § 271(e)(2)(A). (Pl's 

Compl. [1].) The next day, Cumberland filed a Citizen Petition with the FDA, requesting that the 

FDA not approve any ANDA for Acetadote. (Citizen Petition, Ex. 2 to Defs.' Opp'n at 2.)

In the months following the filing of this suit, Mylan filed a motion to dismiss [42] and a 

motion for summary judgment [52]. Subsequently, Plaintiff amended its complaint in May 2013, 

clarifying its allegations and adding, among other things, a second count of infringement related 

to the '445 patent. (Pl.'s Am. Compl. [126].) As a result of the amended complaint, Mylan's 

motion to dismiss was stricken and its motion for summary judgment withdrawn without 

prejudice to later renewal of Mylan's request for fee shifting. (Minute Order of May 30, 2013 

[136].)

The parties now dispute three terms in the '356 and '445 patents. They have submitted 

a series of claim construction briefs, and the court conducted a claim construction hearing in 

August 2013 [174]. The court addresses the disputed language below.

DISCUSSION

I. Legal Standards Governing Claim Construction

Because an invention is defined by the claims of the patent, claim construction—the 

process of giving meaning to the claim language—defines the scope of the invention. Phillips v. 

AWH Corp., 415 F.3d 1303, 1311–12 (Fed. Cir. 2005) (en banc) (citing 35 U.S.C. § 112). Claim 

construction is a matter of law for the court to determine. Markman v. Westview Instruments,

Inc., 517 U.S. 370, 391 (1996). As the Federal Circuit clarified in Phillips, the court begins its
7

claim construction analysis with the words of the claims themselves, giving those words their 

ordinary and customary meaning, that is, the "meaning that the term would have to a person of 

ordinary skill in the art in question at the time of the invention." Phillips, 415 F.3d at 1312–13. 

And that person is assumed to read the claim terms "in the context of the entire patent, including 

the specification." Id. In certain circumstances, however, "the specification may reveal an 

intentional disclaimer, or disavowal, of claim scope by the inventor." Id. at 1316. In such cases, 

courts "interpret[] the claim more narrowly than [they] otherwise would to give effect to the 

inventor's intent to disavow a broader claim scope." Ventana Med. Sys. v. Biogenex Labs., Inc., 

473 F.3d 1173, 1181 (Fed. Cir. 2006) (citing Phillips, 415 F.3d at 1316).

In addition to reading the claim terms in the context of the specification, the court may 

also consider the record of the patent's prosecution, as the record is evidence of how both the 

inventor and the Patent and Trademark Office understood the patent. Phillips, 415 F.3d 

at 1317. The court must, however, be mindful that the prosecution history represents an 

"ongoing negotiation," so it "often lacks the clarity of the specification and thus is less useful for 

claim construction purposes." Id. The specification, on the other hand, "is always highly 

relevant to the claim construction analysis . . . [;] it is the single best guide to the meaning of a 

disputed term." Id. at 1315. Finally, in some cases, the court must go beyond the claim, the 

specification, and the prosecution history—the so-called intrinsic evidence—to consider extrinsic 

evidence such as technical dictionaries, treatises, and expert testimony. Id. at 1317-18. That 

extrinsic evidence is deemed less reliable than the intrinsic evidence for several reasons 

outlined by the Federal Circuit in Phillips. Id. at 1318–19.

With these legal standards in mind, the court turns to construction of the disputed terms 

in the patents-in-suit.
8

II. Free From a Chelating Agent/Free of a Chelating Agent

Claim Term Plaintiff's Proposed 

Construction

Defendants' Proposed 

Construction

"Free From A Chelating Agent"

& "Free Of A Chelating Agent"

Lacking one or more added 

chelating agents.

Lacking any chelating agents

The term "free of/from a chelating agent" appears in claims 1, 7, 8, and 9 of the '356

patent. Claim 1 of the '445 patent also includes the similar phrase "free of chelating agents." 

Although the parties agree that "free of chelating agents" means "lacking any chelating agents"

(Joint Claim Construction Chart [172] at 4), they differ as to the meaning of the similar 

expressions "free of a chelating agent" and "free from a chelating agent." The parties do agree, 

however, that "free of a chelating agent" and "free from a chelating agent" share a meaning. As 

such, the parties both use—and the court adopts—the shorthand "free of/from a chelating 

agent" when discussing these disputed phrases. Mylan argues that this contested term is 

identical in meaning to "free of chelating agents" (i.e., "lacking any chelating agents"). (Id.) 

Cumberland disagrees, and takes the position that the phrase should be read as "lacking one or 

more added chelating agents." (Id. (emphasis in original).) Thus, the parties' respective 

constructions of "free of/from a chelating agent" actually differ in two key respects: (1) whether 

"a" means "any" or "one or more"; and (2) whether the phrase limits all chelating agents 

(including those present as impurities) or only those that are "added" to the composition.

A. Meaning of "A"

At first blush, the phrases "lacking any" and "lacking one or more" seem to be 

synonymous. There is an important distinction, however, between the proposed constructions. 

Mylan's interpretation (i.e., "lacking any chelating agents") describes a composition completely 

devoid of any chelating agents, while Cumberland's version (i.e., "lacking one or more added 

chelating agents") requires only that at least one otherwise-added chelating agent be absent. 

That is, a composition that falls within Cumberland's construction may contain numerous

chelating agents, so long as it does not include every chelating agent (and also adheres to the 
9

claim's other limitations). The court concludes that Cumberland's reading of "a," though quite

broad in scope, is the proper construction due to the nature of dependent claims and the related 

doctrine of claim differentiation. 

Patent claims may be either independent or dependent. Dependent claims, as their 

name suggests, are claims that refer to and depend on the limitations laid out in a previous 

claim in the patent. A dependent claim is "construed to incorporate . . . all of the limitations of 

the claim to which it refers," and "then specif[ies] a further limitation[.]" 35 U.S.C. § 122. As a 

result, each dependent claim serves to narrow the scope of the invention in relation to the 

claims that precede it. Based on this relationship between dependent and independent claims, 

the concept of claim differentiation provides that the existence of a limitation in a dependent 

claim implies that the independent claim on which it depends is not subject to that limitation. 

See Free Motion Fitness, Inc. v. Cybex Int'l, Inc., 423 F.3d 1343, 1351 (Fed. Cir. 2005). In other 

words, claim differentiation demands a construction under which each claim has a different 

scope and no claim is superfluous. Id. 

Claim differentiation is relevant to a number of asserted claims in the patents-in-suit. For 

instance, Claim 14 of the '356 patent depends on Claim 9. They read as follows:

9. A container comprising: an aqueous pharmaceutical composition 

comprising between 200 and 500 mg/mL acetylcysteine, wherein the composition 

is free of a chelating agent and has a pH of about 6 to less than 7, or 

pharmaceutically acceptable salts thereof, and wherein said composition is in a 

suitable form for intravenous injection; and a headspace consisting essentially of 

a pharmaceutically inert gas. . . .

14. The composition of claim 9, wherein the chelating agent is EDTA.

'356 patent (emphasis added). As Plaintiff points out, Defendants' construction of "a" would 

render Claim 14 superfluous. (Pl.'s Resp. Br. at 12) That is, if "a" means "any," then Claim 9 

would describe a composition without any chelating agents whatsoever, and Claim 14's 

limitation would add nothing to the patent. Defendant responds by pointing out that claim 

differentiation is "not absolute in its application," rather "it is just one of many tools used by 
10

courts in the analysis of claim terms." (Defs.' Reply Br. [170] at 8 (quoting ERBE Elektromedizin 

GmbH v. Canady Techn. LLC, 629 F.3d 1278, 1286 (Fed. Cir. 2010)).) Further, Mylan argues, 

adhering to the claim differentiation doctrine in this instance would run afoul of Federal Circuit 

guidance that "[a] claim construction that renders asserted claims facially nonsensical cannot be 

correct." Becton, Dickinson & Co. v. Tyco Healthcare Grp., LP, 616 F.3d 1249, 1255 (Fed. Cir. 

2010). Mylan suggests that Plaintiff's construction would be "nonsensical," because "the only 

composition that falls outside of [Cumberland's construction] is that which contains every single 

chelating agent in the world."

8

 (Defs.' Reply Br. at 8.) While Cumberland's interpretation does 

render the scope of the disputed term especially broad, an especially broad term does not 

necessarily render the claim "facially nonsensical." The case Defendants cite for this 

proposition is illustrative of the distinction. In Becton, the Federal Circuit rejected a proposed 

construction as "nonsensical" because it would have rendered the invention a "physical 

impossibility."

9 Becton, 616 F.3d at 1255. The Becton court, in turn, relied on Schoenhaus, a 

case that rejected a proposed construction that would have resulted in a claim that read: "[a] 

footwear product having as an element thereof [a shoe built to have the shape of the interior of 

 8 Mylan's assertion ignores the remaining limitations within the claims in question. 

Claim 1 of the '356 patent not only describes a composition that is "free of a chelating agent," 

but also one that is "stable," contains "between 200 and 250 mg/mL acetylcysteine," "is in a 

suitable form for intravenous injection," has a pH "from 6 to 7," and "is sealed in an airtight 

container." '356 patent, col. 9 ll. 17–21. 

9 In Becton, the plaintiff was the assignee of a patented design for a safety needle 

intended to prevent accidental needle stick injuries. The invention consisted of four distinct 

elements: (1) a needle, (2) a guard that rides on the needle, (3) a hinged arm attached to the 

guard, and (4) a spring means connected to the hinged arm. When not in use, the needle 

guard covered the needle's tip. The plaintiff argued that the "spring means" and the "hinged 

arm" were the same thing. The Federal Circuit found this construction "nonsensical," because 

the patent described the spring means as being "connected to" the hinged arm and also 

"extending between" the hinged arm and a mount. Thus, the plaintiff's construction would 

require the hinged arm to be "connected to" itself and also "extend between" itself and the 

mount, which the Federal Circuit deemed "a physical impossibility." Becton, 616 F.3d 

at 1254–55.
11

the insert]." Schoenhaus v. Genesco, Inc., 440 F.3d 1354, 1357 (Fed. Cir. 2006). Both of these 

cases rejected proposed constructions that can be described as illogical, internally inconsistent, 

or physically impossible. By contrast, Cumberland's construction of "a" is neither illogical nor 

physically impossible; it is simply broad. Further, as discussed above, this is the only 

interpretation of the '356 patent's independent claims that does not render its dependent claims 

redundant.

Mylan also objects to Plaintiff's construction as (1) inconsistent with the plain and 

ordinary meaning of the phrase; (2) an attempt to "re-write claim language" to reclaim ground 

surrendered in prosecution; and (3) inconsistent with a distinction drawn against prior art during 

prosecution. (Defs.' Opening Br. at 14–16.) These objections misconstrue the disagreement 

between the parties and the relevant prosecution history.

First, Mylan argues that the terms "free of" and "free from" forbid the presence of any 

chelating agent based on the "widely accepted" definition of their meaning as "lacking" or "not 

having or using." (Defs.' Opening Br. at 12.) But this argument misses the actual point of 

disagreement here. The parties, in fact, agree that "free of" and "free from" should be construed 

as "lacking." (Joint Construction Chart at 4.) The real argument is about what exactly the 

composition is lacking. On this score, as Plaintiff points out, the ordinary meaning of "a," 

according to the Federal Circuit, is "one or more."10 (Pl.'s Resp. Br. at 11–12 (citing Baldwin 

Graphics Sys., Inc. v. Siebert, Inc., 512 F.3d 1338, 1342–43 (Fed. Cir. 2008)).)

 10 Mylan argues that the ordinary meaning of "a" should not apply here because, 

unlike in the cases cited by Cumberland, in this instance the word is used as part of "negative 

claim limitations" (i.e., "Cumberland defined its invention by what it is not."); and, when used in a 

negative sense, "a" means "any." (Defs.' Reply Br. at 4.) Mylan's position inaccurately 

represents the way "a" is used in the English language, however. In reality, the meaning of "a" 

as plural or singular depends significantly on context. In some instances, even when one 

defines things by what they lack, "a" does mean "any" ("I don't have a chance"); but in other 

instances it may still mean "one" ("My shirt is missing a button"). 
12

Second, Mylan points to amendments during prosecution that modified the claim 

limitations on chelating agents to argue that Cumberland's proposed construction here seeks to 

reclaim ground it was forced to cede in prosecution. As discussed above, the initial application 

used the term "substantially free of EDTA," which was deemed ambiguous. That term was 

subsequently changed to "less than [a certain percentage] w/v EDTA" on August 12, 2008. 

Additional amendments on November 16, 2010 altered this language to "less than [a certain 

percentage] w/v of a chelating agent." In the end, the specific w/v limits on chelating agents 

were replaced with "free of/from a chelating agent." The effect of this series of amendments, 

according to Mylan, was to repeatedly narrow the scope of the claims. Based on this theory,

Defendants argue that the November 2010 amendments served to "exclude [a certain 

percentage of] all chelating agents" rather than just EDTA; and the ultimate change to "free 

of/from a chelating agent" was intended to exclude any amount of any chelating agent. Mylan's 

interpretation of the prosecution history fails, however, because it ignores the fact that claim 

limitations on "chelating agents" never existed without dependent claims that specifically limited

EDTA. Thus, Cumberland's insistence on adhering to the principle of claim differentiation now 

is not a last-ditch effort to reclaim ceded territory; rather, it is consistent with each iteration of the 

claims throughout prosecution. 

Finally, Defendant argues that Plaintiff's construction is inconsistent with the position it 

took concerning prior art during prosecution. On March 2, 2011, the Examiner rejected 

Cumberland's application for the '356 patent as anticipated by European Patent 0639375 ("EP 

'375"). (Defs.' Opening Br., Ex. C, at 748–49.) On July 22, 2011, Cumberland amended11 its 

application and responded to the Examiner's rejection based on EP '375. Mylan characterizes 

 11 This amendment did not modify the amount or type of chelating agents in the 

composition; rather it added a clause specifying that the composition is "sealed in an airtight 

container" with "headspace . . . occupied by a pharmaceutically inert gas." (Defs.' Opening Br., 

Ex. C, at 761.)
13

Plaintiff's response as "argu[ing] that EP '375 disclosed an acetylcysteine composition that 

contained sodium bicarbonate, which is 'a compound that has chelating properties,' and, 

therefore, did not read on [Plaintiff's] claims which exclude all chelating agents." (Defs.'

Opening Br. at 8-9.) This mischaracterizes the prosecution history. In reality, Plaintiff did not 

distinguish its invention from EP '375 based on an argument that Cumberland's claims excluded 

all chelating agents. Rather, the sentence following the passage quoted by Mylan above states 

that, "EP '375 fails to disclose or suggest an acetylcysteine composition compris[ing] less than 

0.05% w/v of a chelating agent."

12 (Defs.' Opening Br., Ex. C, at 773.) The chelating content of 

EP '375 was also only one of several grounds on which Plaintiff sought to distinguish its 

invention, including that the prior art "fails to disclose or suggest at least . . . a composition 

sealed in an air-tight container, and . . . a composition with a headspace volume occupied by an 

inert gas." (Id.) 

B. "Added" Chelating Agents

The second source of disagreement between the parties regarding the term "free of/from 

a chelating agent" is whether the phrase refers to all chelators or only those added to the 

composition (i.e., not those included merely as impurities). The plain meaning of the term, as 

Defendants correctly observe, would reach any chelating agent, not just those added to the 

composition. (Defs.' Opening Br. at 13.) 

Surprisingly, Plaintiff does not address this aspect of its proposed construction head-on: 

neither its Markman presentation, its response brief, nor its supplemental reply brief explicitly 

argues why the word "added" should be read into the term "free of/from a chelating agent." 

Based on this notable omission, it appears that Cumberland may have included the word 

 12 The EP '375 composition is 9.52% sodium bicarbonate, which has chelating 

properties. (Defs.' Opening Br., Ex. C, at 773.) Thus, EP '375 contains considerably more than 

the 0.05% w/v of a chelating agent that was recited in Plaintiff's claims at that time.
14

"added" in its proposed construction to reinforce its interpretation of "acetylcysteine" as

including its associated impurities (discussed below). As such, Plaintiff may have considered its

arguments in favor of including impurities in the definition of acetylcysteine as relevant to this 

issue, as well. Two such arguments are particularly relevant: first, Cumberland points to 

numerous passages of the specification which allow for the presence of chelating agents as 

impurities. (Pl.'s Resp. Br. at 6–8.) Indeed, the very innovation of Plaintiff's invention was the 

discovery that an acetylcysteine composition could remain stable "without the addition of a 

chelating agent." '356 patent, col. 2 l. 48. Second, Cumberland argues that Mylan's 

construction of "acetylcysteine" without its impurities would exclude certain embodiments in the 

specification in violation of Federal Circuit precedent. (Pl.'s Resp. Br. at 5–6 ("[a] claim 

construction that excludes the preferred embodiments . . . in the patent specification 'is rarely, if 

ever, correct and would require highly persuasive evidentiary support' to be sustained.") 

(quoting Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1583 (Fed. Cir. 1996)).) This 

argument is relevant to the inclusion of "added" in the construction of "free of/from a chelating 

agent," because one embodiment in the '356 patent describes a composition in which "chelating 

agents are not added . . . but may be present otherwise. For instance, the chelating agent may 

be present as an impurity or undesired contaminant." '356 patent, col 3 l. 67–col. 4 l. 3. 

Defendants respond by pointing out that the specification is actually inconsistent as to 

whether it excludes the presence of chelating agents or simply their addition. For instance, at 

one point, the specification describes the invention as a composition of acetylcysteine capable 

of maintaining stability "without the need of a chelating agent." (Def.'s Reply Br. at 7 (quoting 

'356 patent, col. 4 ll. 6–11.) They further argue that the including the word "added" in the 

construction of free of/from a chelating agent "wrongly imports a process limitation into 

composition claims." (Defs.' Reply Br. at 8.) 
15

Without reaching the merits of either of these arguments, however, the court is satisfied 

that the intrinsic evidence here provides no basis for disregarding the ordinary meaning of the 

disputed term at issue. The court's interpretation of "a" as "one or more" (discussed above) 

moots both of Plaintiff's potential arguments in favor of reading "added" into this disputed term. 

Even without reading the word "added" into the construction of "free of/from a chelating agent" 

(as construed above), the term would not exclude the embodiment Plaintiff cites (i.e., one that 

contains chelating agents as impurities). In fact, so long as a composition does not contain all

chelating agents—whether as impurities or added ingredients—the term "free of/from a 

chelating agent" would not exclude it. Accordingly, the court adopts the following construction 

for "free of/from a chelating agent": "lacking one or more chelating agents."

III. Acetylcysteine

Claim Term Plaintiff's Proposed 

Construction

Defendants' Proposed 

Construction

"Acetylcysteine" An antioxidant having a molecular 

weight of 163.2 and the following 

chemical structure: 

Acetylcysteine is the nonproprietary 

name for the N-acetyl derivative of 

the naturally occurring amino acid, 

L-cysteine (also known as N-acetylL-cysteine and NAC) and 

impurities associated therewith.

An antioxidant having a molecular 

weight of 163.2 and the following 

chemical structure: 

Acetylcysteine is the nonproprietary 

name for the N-acetyl derivative of 

the naturally occurring amino acid, 

L-cysteine (also known as N-acetylL-cysteine and NAC).

The term "acetylcysteine" appears in every asserted claim of both patents-in-suit. 

Cumberland proposes reading "acetylcysteine" as "[t]he nonproprietary name for the N-acetyl 

derivative of L-cysteine (also known as N-acetyl-L-cysteine and NAC) and impurities associated 
16

therewith." (Joint Claim Construction Chart at 4 (emphasis added).) Defendants, on the other 

hand, would construe the term to reach only acetylcysteine and not its impurities.

13 (Id.) 

Cumberland bases its construction of acetylcysteine on both the specification and the 

"ordinary meaning" of the term. (Pl.'s Resp. Br. at 6–9.) Notably, the specification seems to 

expressly anticipate impurities in its definition of "acetylcysteine": "Acetylcysteine includes 

derivatives of acetylcysteine, and pharmaceutically acceptable salts thereof." '356 patent, col. 4

ll. 41–42. The specification also includes a table—"Table 1"—that tracks the stability of 

acetylcysteine compositions over time. Id., col. 8 55–70. The table identifies each of the 

components added to create the composition, as well as "various impurities, including Lcysteine,14 impurity C (disulfide), impurity D, and other impurities or degradation products." '356 

patent, col. 8 ll. 32–34. The "ordinary meaning" of acetylcysteine also supports Cumberland's 

construction, as “impurities normally associated with the component of a claimed invention are 

implicitly adopted by the ordinary meaning of the components themselves.” Conoco Inc. v. 

Energy & Envtl. Int’l, L.C., 460 F.3d 1349, 1360–61 (Fed. Cir. 2006).

Mylan agrees that the ordinary meaning of acetylcysteine would include its impurities, 

but nevertheless argues that the specification here provided an "express definition [that] 

supersedes Cumberland's argument for interpretation based on plain and ordinary meaning." 

(Defs.' Reply Br. at 11 (quoting Phillips, 415 F.3d at 1316) (“[T]he specification may reveal a 

 13 Mylan initially argued that acetylcysteine itself is a "chelating agent." Thus, 

based on Mylan's proposed construction of "free of/from a chelating agent" (discussed above), 

the claims at issue would paradoxically include acetylcysteine and be "free of/from" it at the 

same time. In their reply brief, however, Defendants withdrew this interpretation and 

acknowledged that "'chelating agent' need not be construed to include 'acetylcysteine.'" (Defs.' 

Reply Br. at 10.)

14 The parties disagree about L-cysteine in two respects, neither of which the court 

must determine at this time: (1) whether L-cysteine is a chelating agent (Mylan says yes, 

Cumberland says no) (Defs.' Opening Br. at 17 n.4); and (2) whether it is possible to have a 

composition of acetylcysteine without L-cysteine being present (Mylan again says yes; 

Cumberland says no) (Defs.' Supp. Br. [179] at 1; Pl.'s Supp. Reply Br. [181] at 3–4).
17

special definition given to a claim term by the patentee that differs from the meaning it would 

otherwise possess. In such cases, the inventor’s lexicography governs.”) (internal citations

omitted)).) But this argument relies on Mylan's construction of "free of/from a chelating agent," 

which the court rejected above. As Defendants see it, Cumberland disavowed the ordinary 

meaning of acetylcysteine by excluding all chelating agents in the claims that contain the phrase 

"free of/from a chelating agent." (Defs.' Reply Br. at 11.) Based on that theory, acetylcysteine 

cannot be construed to include impurities insofar as those impurities may be chelating agents. 

But, as the court discussed at length above, Mylan's construction of "free of/from a chelating 

agent" is incorrect; and, as a result, there is no reason to understand that term as a disavowal of 

the ordinary meaning of acetylcysteine. Accordingly, the court adopts Plaintiff's proposed 

construction of "acetylcysteine" as "the nonproprietary name for the N-acetyl derivative of the 

naturally occurring amino acid, L-cysteine (also known as N-acetyl-L-cysteine and NAC) and 

impurities associated therewith." 

IV. Stable Aqueous Pharmaceutical Composition

Claim Term Plaintiff's Proposed 

Construction

Defendants' Proposed 

Construction

"Stable Aqueous 

Pharmaceutical 

Composition"

A composition that exhibits minimal 

change for at least 3 months relative 

to when it was manufactured.

A composition that exhibits 

minimal change over time relative 

to when it is manufactured.

The final disputed term is "stable aqueous pharmaceutical composition." Under 

Plaintiff's construction, a composition is stable if it "exhibits minimal change for at least 3 

months" from manufacture. (Joint Construction Chart at 4.) Defendants, meanwhile, argue for 

an interpretation that requires stability "over time" rather than "for at least three months." (Id.) 

The specification defines a composition as "stable" if it "exhibits minimal change over 

time relative to when it is manufactured." '356 patent, col. 3 ll. 43–44. Mylan argues that "the 

unambiguous language of the specification" supports Defendants' construction. (Defs.' Reply 

Br. at 12.) The specification goes on, however, to clarify that "[s]tability is measured at various 
18

time points . . . as described in Example 3." Id. at 44–51. Example 3, in turn, identifies the 

process by which Plaintiff tested the stability of its invention: various acetylcysteine formulations 

were kept at 25 or 40 degrees Celsius. Sample vials of each iteration were removed after three 

months, six months, and twelve months, and their contents were compared to the initial 

compositions. Id. at c. 8 ll. 13–53. Example 3 refers to Table 1, which catalogues the results of 

these tests:

'356 patent at col. 8 l. 54–col. 9 l. 14. 

Based on Example 3 and Table 1, Cumberland argues that the specification "identifies a 

time period of 3 months as the minimum time point for stability" by first evaluating the 

formulations at that point. (Pl.'s Resp. Br. at 16.) Plaintiff further argues that "[c]laim 

differentiation reinforces that three months is the minimum time point," because Claims 5 and 6 

demand longer periods of stability: twelve months at 25 ̊C and six months at 40 ̊C, respectively. 

(Id. at 17.) Finally, Cumberland points to two pieces of extrinsic evidence to support its 

construction. (1) FDA guidance that advises "[f]or products with a proposed shelf life of at least 

Time

point

Disodium

EDTA Temp

NAC

Content

LCysteineImpurity C 

(Disulfide) Impurity D

Highest 

Unknown

Total 

Unknowns

Initial 0.00% N/A 202.4 0.150 0.550 0.180 0.010 0.020

Initial 0.02% N/A 203.9 0.190 0.440 0.230 0.030 0.050

Initial 0.05% N/A 204.7 0.200 0.500 0.300 0.040 0.100

3 Mos. 0.00% 25 ̊ C 204.2 0.181 0.482 0.137 0.053 0.080

3 Mos. 0.00% 40 ̊ C 201.8 0.370 0.540 0.900 0.070 0.132

3 Mos. 0.02% 25 ̊ C 204.9 0.259 0.436 0.191 0.074 0.141

3 Mos. 0.02% 40 ̊ C 204.5 0.463 0.467 0.142 0.065 0.183

3 Mos. 0.05% 25 ̊ C 206.1 0.299 0.444 0.214 0.044 0.119

3 Mos. 0.05% 40 ̊ C 205.4 0.532 0.507 0.165 0.045 0.154

6 Mos. 0.00% 25 ̊ C 202.4 0.262 0.523 0.106 0.013 0.013

6 Mos. 0.00% 40 ̊ C 201.7 0.707 0.509 0.053 0.133 0.133

6 Mos. 0.02% 25 ̊ C 205.9 0.338 0.391 0.167 0.013 0.013

6 Mos. 0.02% 25 ̊ C 207.1 0.369 0.483 0.186 0.013 0.013

6 Mos. 0.05% 40 ̊ C 204.6 0.932 0.509 0.104 0.135 0.135

6 Mos. 0.05% 40 ̊ C 204.3 0.856 0.525 0.093 0.135 0.135

12 Mos. 0.00% 25 ̊ C 204.5 0.364 0.597 0.079 0.034 0.071

12 Mos. 0.02% 25 ̊ C 206 0.435 0.475 0.134 0.042 0.130

12 Mos. 0.05% 25 ̊ C 207.1 0.514 0.435 0.160 0.055 0.122
19

12 months, the frequency of testing at the long-term storage condition should normally be every 

3 months over the first year " (id. at 18 (quoting "Guidance for Industry," FDA, Ex. S to Pl.'s 

Resp. Br.)); and (2) Defendants' use of three months as a minimum for stability testing in its own 

ANDA application. (Id. at 18 (citing ANDA Application, Ex. T to Pl.'s Resp. Br.; Stability data, 

Ex. U to Pl.'s Resp. Br.)

Plaintiff's argument here relies on the fact that the specification's first tests of stability 

were conducted after three months. Cumberland supports its interpretation with citations to a 

pair of cases from the Federal Circuit in which that court read numerical limitations into claims 

based on the specification. (Pl.'s Resp. Br. at 19 (citing Amazin’ Raisins Int’l, Inc. v. Ocean 

Spray Cranberries, Inc., 306 F. Appx. 553 (Fed. Cir. 2008); Sinorgchem Co., Shandong v. Int’l 

Trade Comm’n, 511 F.3d 1132 (Fed. Cir. 2007)).) As Mylan points out, however, the terms in 

those cases are easily distinguishable from the disputed terms here, because, unlike here, the 

specifications in those cases took steps to explicitly define the terms in dispute using numerical 

limitations. In Amazin' Raisins, the Federal Circuit affirmed the district court's construction of 

"dried fruit" as "fruit from which natural moisture has been removed which has about 10 to 18% 

moisture remaining" based on the following text from the specification: "Any dried fruit which 

contains between about 10% to 18% moisture may be employed." 306 Fed. Appx. at 556-557. 

Similarly, in Sinorgchem, the patentee explicitly defined a disputed claim term ("controlled 

amount") in the specification by using a specific numerical limitation ("up to about 4% H20"), and 

the Federal Circuit found the inventor's intention dispositive. 511 F.3d at 1136. While the '356 

specification does refer to a measure of stability after three months, this reference is not 

definitive in the same sense as the numerical values in Amazin' Raisins and Sinorgchem. In 

fact, the specification here provides a definition of "stable" that, like Mylan's construction, is 

silent as to time.

Plaintiff's remaining arguments based on claim differentiation and extrinsic evidence can 
20

also be dismissed. Cumberland seems to suggest that claim differentiation demands that an 

independent claim must require stability over a shorter period of time than any limitation added 

by its dependent claims. But the claims here belie that very notion: Claim 6, which depends on 

Claim 5, only requires stability for six months at 40 ̊C, while Claim 5 requires stability for "at 

least 12 months at 25 ̊C." '356 patent, col. 9 ll. 33–38. Plaintiff's extrinsic evidence is also 

insufficient to support its construction, as Plaintiff asks the court to rely on FDA guidance that 

Plaintiff itself did not follow. As Cumberland itself acknowledges, the FDA suggests that testing 

"should normally be every 3 months over the first year," yet Plaintiff tested the stability of its 

compositions only at three, six, and twelve months. This guidance, and the fact that Defendants 

also tested stability first after three months, is not sufficient to establish an industry norm that 

requires Plaintiff's proposed construction of "stability."

Nothing in the intrinsic (or extrinsic) record here justifies a construction of "stable" that 

differs from the plain meaning of the term as explicitly defined in the specification. Accordingly, 

the court adopts the following construction for "stable aqueous solution": "a composition that 

exhibits minimal change over time relative to when it is manufactured." 

CONCLUSION

Claim terms in the '356 and '445 patents are construed in accordance with the foregoing.

ENTER:

:

Dated: February 26, 2014 _________________________________________

REBECCA R. PALLMEYER

United States District Judge