Source: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-cand-3_06-cv-00100/USCOURTS-cand-3_06-cv-00100-8/pdf.json

Nature of Suit Code: 830
Nature of Suit: Patent
Cause of Action: 35:271 Patent Infringement

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United States District Court

For the Northern District of California

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United States District Court

For the Northern District of California

IN THE UNITED STATES DISTRICT COURT

FOR THE NORTHERN DISTRICT OF CALIFORNIA

DEPOMED, INC.,

Plaintiff,

 v.

IVAX CORPORATION,

Defendant. /

No. C 06-00100 CRB

ORDER

This suit involves the alleged infringement by Ivax Corp. (“Ivax”) of two United

States patents issued to DepoMed, Inc. (“DepoMed”). The patents teach compositions and

methods for the delivery of highly soluble drugs over an extended period of time to the upper

gastrointestinal (“GI”) tract. 

The parties submitted a Joint Claim Construction and Prehearing Statement (“Joint

Statement”) in which they report agreement as to the meaning of one term, and propose

constructions of five disputed terms and phrases. (Docket No. 58, Aug. 28, 2006). Upon

consideration of the briefing and the arguments made at the Markman hearing, the Court now

sets forth constructions of the disputed terms.

I. BACKGROUND

DepoMed is the assignee of U.S. Patent Nos. 6,340,475 and 6,635,280 (the “’475

patent” and the “’280 patent,” respectively), both of which are entitled “Extending the

duration of drug release within the stomach during the fed mode.” The ’280 patent is a

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1 The specifications of the two patents differ only by the cross-references made to related

applications and spacing changes incident to publication. Unless a passage is unique to the ’280

patent, such as the claims, only the ’475 patent will be cited.

2

continuation of the ’475 patent, which itself is a continuation-in-part of an application now

abandoned. See ’280 patent at [63]. These two patents, therefore, provide substantively

identical disclosures.1

The patents disclose oral drug dosage forms--that is, pills or tablets suitable for

ingestion--that incorporate doses of a drug into a polymeric matrix. The polymeric matrix

swells on contact with water that is present in the stomach as gastric fluid. Such swelling

serves two purposes. First, it hinders passage of the doasge form out of the stomach, which

allows the dosage form to remain in the stomach for a longer period of time. Second, the

swelling retards the rate of diffusion of the incorporated drug out of the tablet and into the

upper GI tract, thereby moderating the rate at which the drug is released. The invention thus

promotes delivery of certain drugs to the upper GI tract, thereby enhance the efficacy of the

drugs contained therein, or preventing the deleterious consequences of delivery to the lower

GI tract. The invention also also helps avoid transient overdosing by extending delivery of

the drug.

It is critical to the operation of the invention that the dosage form is administered

following a meal, when the stomach is in the “fed mode,” a term used to describe the state of

the stomach lasting for roughly six hours after ingetion of food. In the fed mode, the

pylorus--the passageway between the stomach and the large intestine--constricts and permits

only liquids and small particles to pass. Larger objects are retropelled and remain in the

stomach for further digestion. To perform as claimed, the dosage form must be large enough

that it remains in the stomach and avoids passage through the constricted pylorus.

The ’475 and ’280 patents particularly teach that highly soluble drugs are capable of

delivery by swellable polymers of high molecular weight that do not depend on erosion of

the polymer. Unlike other controlled drug delivery systems known to the art that rely upon

the dual mechanisms of swelling and erosion in order to deliver a drug, experiments

disclosed in the DepoMed patents demonstrate that formulations of the invention gave a

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controlled release of the drug for 4 to 6 hours (or longer), and also that the polymers were

retained in the stomach, when given during the fed mode, for a similar period of time. One

of the claimed properties of the dosage form is that delivers substantially all of the

incorporated drug over this timeframe, which corresponds to the typical duration of the fed

mode. 

II. STANDARD OF REVIEW

Claim construction is a matter of law for the court to decide. Markman v. Westview

Instruments, Inc., 57 F.3d 967, 979 (Fed. Cir. 1995), aff’d, 517 U.S. 370, 372 (1996). When

construing claims, a court first looks to intrinsic evidence of record, and thereafter, if

appropriate, to extrinsic evidence. Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582

(Fed. Cir. 1996). Intrinsic evidence comprises the patent claims, the specification, and, if

entered into evidence, the prosecution history. Id. Intrinsic evidence also comprises the

prior art cited in a patent or during the prosecution. Kumar v. Ovonic Battery Co., 351 F.3d

1364, 1368 (Fed. Cir. 2003). In most cases, the intrinsic evidence alone will determine the

proper meaning of the claim terms. Vitronics, 90 F.3d at 1583. 

When construing claims, the analysis begins with, and must focus on, the language of

the claims themselves. Interactive Gift Exp., Inc. v. Compuserve Inc., 256 F.3d 1323, 1331

(Fed. Cir. 2001). If the claim language is clear on its face, then the rest of the intrinsic

evidence is considered only to determine whether any deviation from the plain meaning is

specified. Id. Deviation may be warranted if, for example, the patentee has “chosen to be his

own lexicographer,” or if the patentee has disclaimed a certain portion of the claim scope that

would otherwise be afforded by the plain meaning. Id. (citations omitted). Where the claim

language is not clear, other intrinsic evidence is used to resolve the lack of clarity. Id.

Generally, a court gives the words of a claim their ordinary and customary meaning. Phillips

v. AWH Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005). The “ordinary and customary

meaning of a claim term 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, i.e., as of the effective filing date of the

patent application.” Id. at 1313. The context in which a word appears in a claim informs the

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construction of that word. Id. at 1314. Where there are several common meanings, the

patent disclosure “serves to point away from the improper meanings and toward the proper

meanings.” Brookhill-Wilk 1, LLC v. Intuitive Surgical, Inc., 334 F.3d 1294, 1300 (Fed.

Cir. 2003) (citation omitted). If more than one definition is consistent with the usage of a

term in the claims, the term may be construed to encompass all consistent meanings. Texas

Digital Sys., Inc. v. Telegenix, Inc., 308 F.3d 1193, 1203 (Fed. Cir. 2002). 

Claims must be read in light of the specification. Markman, 52 F.3d at 979. The

specification “is the single best guide to the meaning of a disputed term.” Vitronics, 90 F.3d

at 1582. Where a claim term has multiple, yet potentially consistent, definitions, the rest of

the intrinsic record, beginning with the specification, provides further guidance. BrookhillWilk, F.3d at 1300. If the patentee explicitly defined a claim in the specification, that

definition trumps the ordinary meaning of the term. CCS Fitness v. Brunswick Corp., 288

F.3d 1359, 1366 (Fed. Cir. 2002). The specification also may define a term by implication, 

Phillips, 415 F.3d at 1321, or it may reveal a disclaimer of the claim scope by indicating that

the invention and all of its embodiments only occupy part of the broad meaning of a claim

term. SciMed Life Sys. v. Advanced Cardiovascular Sys., 242 F.3d 1337, 1343-44 (Fed. Cir.

2001). 

It is error, however, to import a limitation from the specification into the claim. 

Liebel-Flarsheim Co. v. Medrad, Inc., 358 F.3d 898, 904 (Fed. Cir. 2004). Standing alone,

an embodiment disclosed in the specification does not limit the claims. Id. at 906. Even

when the specification describes only a single embodiment, the claims of the patent are not to

be construed as restricted to that embodiment unless the patentee demonstrates a clear

intention to limit the claim scope using “words or expressions of manifest exclusion or

restriction.” Teleflex, Inc. v. Ficosa N. Am. Corp., 299 F.3d 1313, 1327 (Fed. Cir. 2002). 

Absent clear statements of scope, courts must follow the language of the claims and not that

of the written description provided by the specification. Id. at 1328; see also Specialty

Composites v. Cabot Corp., 845 F.2d 981, 987 (Fed. Cir. 1988) (stating that a limitation

should not be read into the claims unless a specification so requires).

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Conversely, a construction that excludes a preferred embodiment is “rarely, if ever,

correct.” Pfizer Inc. v. Teva Pharm., USA, Inc., 429 F.3d 1364, 1374 (Fed.Cir. 2005)

(quoting Sandisk Corp. v. Memorex Prods., Inc., 415 F.3d 1278, 1285 (Fed. Cir. 2005)). 

Courts require highly persuasive evidence that the claims do not encompass a preferred

embodiment. Vitronics, 90 F.3d at 1583.

III. DISCUSSION

 All the disputed terms are found in claim 1 of the ’475 patent or claim 1 of the

’280 patent. Those claims are reproduced here for reference:

Claim 1. A controlled-release oral drug dosage form for releasing a drug whose

solubility in water is greater than one part by weight of said drug in ten parts by

weight of water, said dosage form comprising a solid polymeric matrix with said

drug dispersed therein at a weight ratio of drug to polymer of from about 15:85 to

about 80:20, said polymeric matrix being one that swells upon imbibition of water

thereby attaining a size large enough to promote retention in the stomach during

said fed mode, that releases said drug into gastric fluid by the dissolution and

diffusion of said drug out of said matrix by said gastric fluid, that upon immersion

in gastric fluid retains at least about 40% of said drug one hour after such

immersion and releases substantially all of said drug within about eight hours after

such immersion, and that remains substantially intact until all of said drug is

released.

’475 patent.

Claim 1. A controlled-release oral drug dosage form for releasing a drug whose

solubility in water is greater than one part by weight of said drug in ten parts by

weight of water, said dosage form comprising one or more polymers forming a

solid polymeric matrix with said drug incorporated therein at a weight ratio of

drug to polymer of from [] 15:85 to [] 80:20, said dosage form being one that

when swollen in a dimensionally unrestricted manner as a result of imbibition of

water is of a size exceeding the pyloric diameter in the fed mode to promote

retention in the stomach during said fed mode, that releases said drug into gastric

fluid by the dissolution and diffusion of said drug out of said matrix by said gastric

fluid, that upon immersion in gastric fluid retains at least about 40% of said drug

one hour after such immersion and releases substantially all of said drug [] after

such immersion, and that remains substantially intact until substantially all of said

drug is released.

’280 patent. The differences beteween the two claims are highlighted by formatting changes

in the block quotes above. Text omitted from claim 1 of the ’475 patent is indicated by

brackets, while text added or substituted into claim 1 of the ’475 patent is indicated by

underlining. The parties have asked the Court to construe five terms and phrases; the

construction of these disputed terms is set forth below. 

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A. “substantially all of said drug”

Claim 1 of the ’475 patent teaches that the dosage form “releases substantially all of

said drug within about eight hours after such immersion,” referring to the period over which

the drug is released from the polymeric matrix into the gastric fluid. The parties dispute the

meaning of the term “substantially all.” While this term is common to claim 1 of both

patents, the Court notes that claim 1 of the ’280 patent omits reference to an eight-hour time

period. The time period over which “substantially all” of the drug is released is not an issue

disputed by the parties. 

Common sense indicates that “substantially all” of a substance refers to some

percentage approaching 100% of the relevant material--in other words, some measure just

short of all of it. Many physical processes and phenomena, however, defy and may even be

incapable of attaining completeness, or may reach completeness at varying rates and with

varying expected degrees of succes. Therefore, each case must be resolved with attention to

its specific facts. The plain meaning of such a term of approximation is rarely apparent from

the claim language alone, and this instance is no different. 

Here, Ivax contends that the amount released within eight hours must be at least 90%

of the total. In particular, Ivax relies on a passage in the ’475 patent indicating that a

“substantial” period of time amounts to at least 90% of the dosing period, and contends that

the term “substantial” therefore generally should mean a level of 90% whenever it is used in

connection with the patent. See ’475 patent at 9:13-16. The cited passage, however, actually

points away from Ivax’s position. First, the passage implies that a substantial period of time

includes periods of time shorter than 90% of the dosing period. Second, despite the fact that

drug release levels are a function of time, what is substantial with respect to one variable

(time) is not necessarily pertinent to another variable (released amount of drug). 

By contrast, DepoMed contends that release of “substantially all of said drug”

indicates the release of about 80% of the drug incorporated into the polymeric matrix.

DepoMed finds support for this position in the examples that demonstrate that roughly

two-thirds (21 out of 31) of the formulations reported in the patent released at least 80% of

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the drug after eight hours. Ivax counters that only three of the samples actually demonstrated

a release between 80% and 90%, and argues the samples therefore provide just as much

support for its preferred interpretation of 90%. These competing contentions, both of which

are reasonable, demonstrate why the proffered compilation provides an inadequate basis for a

definitive construction of the disputed term. Moreover, as a policy matter, an outcome based

solely on the type of testing examples disclosed in the patent would make the construction of

a term turn entirely on the degree of testing that the patentee chose to perform--or to report. 

A firmer foundation, preferably rooted in the science, is necessary.

It is apparent that the release of drug from within a polymeric matrix is dependent on

many factors. Moreover, the rate at which release occurs is subject to the control and

manipulation of a host of variables. See, e.g., ’475 patent at 12:10 - 17:37. For guidance as

to what one of skill in the art would consider to be the release of “substantially all” of a drug

from a delivery vehicle, the Court finds it appropriate to consider, as extrinsic evidence, the

testing guidelines provided by the Food and Drug Administration (FDA) for pharmaceutical

companies engaged the development of controlled release drug dosage forms. The FDA is

the regulatory agency charged with regulating the entry of drugs into the marketplace, and

marketing the drug dosage forms claimed by the patents would require FDA approval. 

Although extrinsic evidence is viewed as “less significant than the intrinsic record,” reliance

on extrinsic sources is valid where it may help understand how one of skill in the art might

use the claim terms. See Phillips, 415 F.3d at 1317-18 (citations omitted). Here, extrinsic

evidence in the form of guidance documents issued by the FDA, the regulatory gatekeeper to

the commercial field, is particularly reliable because it is devoid of defects often associated

with extrinsic works. See id. at 1318. FDA documents are written for those skilled in the

art, and are issued by the single relevant regulatory agency, which thereby avoids the danger

inherent in choosing from an “unbounded universe” of potential extrinsic sources. See id. In

the absence of any strong indication in the intrinsic record as to the boundary of the vague

and approximate term “substantially all,” the extrinsic FDA source offers the clearest insight

into the understanding that one of skill in the art would have of the term.

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DepoMed notes that the FDA advises companies that perform dissolution tests on

extended-release dosage forms that such testing may be stopped when 80% of the drug is

released. Hopfenberg Reply Decl. ¶ 20. The most relevant point is the FDA guidance on

using an in vitro/in vivo correlation (“IVIVC”) to set dissolution specifications--guidance

that was issued by the FDA only eighteen months prior to the filing date of the ’475 patent. 

See Hopfenberg Opening Decl., Exh. M (Guidance for Industry: Extended Release Oral

Dosage Forms: Development, Evaluation, and Application of In Vitro/In Vivo Correlations)

at 1, 16-19. Under all circumstances delineated in this FDA document, the last time point

“should be the time point where at least 80% of the drug has dissolved.” Id. at 17, 18. For

the purpose of assessing product performance and setting specifications of pharmaceutical

products, the FDA considers the release of 80% of the drug to be the relevant endpoint for

release of the drug. In accord with the FDA’s guidance, this Court construes the phrase

“releases substantially all of said drug within about eight hours after such immersion” of

claim 1 of the ’475 patent to mean that at least 80% of the drug has been released after eight

hours.

B. “gastric fluid”

The term “gastric fluid” appears in claim 1 of both the ’475 patent and the ’280 patent. 

DepoMed contends that the term should encompass the fluid of the human stomach, as well

as simulated or artificial formulations of gastric fluid. This latter category encompasses, in

particular, formulations used in laboratory experiments that model the conditions of a human

stomach. Ivax responds that the claim language and written description indicate instead that

the term “gastric fluid” is limited to mean only “fluid in the human stomach,” and that this

interpretation is consistent with the overall purpose of the claimed invention, which is a

controlled release drug delivery vehicle that promotes retention in the stomach.

The claim language does not expressly define “gastric fluid,” and the context does not

restrict the scope of its meaning. On a casual read of the claim, the phrases “promote

retention in the stomach during said fed mode,” and the repeated use of the term “gastric

fluid” lead one to understand that the claimed drug dosage form targets the stomach. A

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closer read, however, leads to the understanding that the claim limitations do not include

locations where certain events must occur, such as in a human stomach. First, the claim is to

a composition, and the limitations simply relay the properties that the dosage form

composition must possess. Second, the phrase “promote retention in the stomach during said

fed mode” relates back to the size that the drug dosage form must achieve by swelling; it

does not require that the drug dosage form actually be in a stomach. The claimed dosage

form is further defined according to its behavior when immersed in “gastric fluid.” When the

dosage form is immersed, the polymeric matrix responds by swelling, and the embedded drug

dissolves and diffuses out of the polymeric matrix to be released into the gastric fluid. This

limitation does not require that the fluid actually be in a stomach, but merely that it be gastric

fluid. The plain meaning gleaned from the claim language is that the drug dosage form is

defined with reference to the stomach and to what happens in gastric fluid, but it does not

require that the claim’s scope be limited to fluid whose properties are manifest only in the

stomach. In other words, the text does not require that gastric fluid be fluid that is actually

within a stomach. 

Moreover, although the term “gastric fluid” is not explicitly defined in the written

description, as many other terms are, it is nonetheless defined by implication. See Phillips,

415 F.3d at 1321. Indeed, certain passages in the specification suggest the use of “gastric

fluid” outside the confines of a stomach. In particular, the specification states: “The amount

polymer will be sufficient however to retain at least about 40% of the drug within the matrix

one hour after ingestion (or immersion in the gastric fluid).” ’475 patent at 9:25-28. This

passage is subject to two interpretations. First, the applicant may have used the parenthetical

for greater precision; that is, although the overt act of taking the pill would be “ingestion,”

but the mode of action is triggered by the subsequent entry into the stomach and “immersion

in gastric fluid.” Under this interpretation, “gastric fluid” would indicate fluid in the

stomach. Under a second reading, however, this parenthetical sets off and distinguishes the

usual route of administration to a patient – that is, “ingestion,” which inevitably leads to

immersion in the gastric juice of the stomach – from an alternative, “immersion,” as

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something that occurs directly and without ingestion. Under the latter construction, the

conclusion is that the patentee contemplated usage of the composition ex vivo. This

alternative reading is supported by the numerous examples describing test results from in

vitro experiments using “modified simulated gastric fluid.” Id. at 12:60, Examples 1-8, 10. 

Passages in a related patent, also issued to DepoMed, similarly uses the term “gastric fluid”

to refer to artificial compositions used in ex vivo testing. See U.S. Patent No. 5,972,389 at

11:1-3 (describing, in Example 1, how pellets are placed into “stirred gastric fluid,” which

fluid is clearly a simulated formulation of gastric juice).

The Court concludes that, although the patent is directed toward a drug dosage form

that is ultimately for use in a patient, and therefore in the human stomach, the claims to the

composition are not necessarily limited to that milieu, as Ivax contends they should be. Ivax

points to the abstract of the patents, highlighting the language stating that “the oral

formulation is designed for gastric retention and controlled delivery of an incorporated drug

into the gastric cavity, and thus administered, the drug is released form the matrix into the

gastric fluid.” Responsive Br. at 9:17-19 (emphasis in original). Yet the abstract, no more

than the rest of the written description, cannot be read into the claims as a limitation. 

Liebel-Flarsheim, 358 F.3d at 904. Second, the cited passage would only implicate the

method claims. See, e.g., ’475 patent at claim 19 (setting forth “a method of administering to

a subject a drug”). The passage does not necessarily imply any such limit on the scope of a

composition claim. Despite the fact that the ultimate goal of the disclosed compositions and

methods is to provide a drug dosage form for treatment of humans, claims to a composition

are broad, and other intermediate uses fall within their scope. 

Neither, though, is the fluid of claim 1 limited only to simulated environments. 

DepoMed points to the term “immersion” as distinguishing between in vivo and ex vivo

environments. The context of the claims and the specification does not support this position. 

Method claims, which clearly refer to steps occurring in the stomach, also use the term

“immersion.” See, e.g., ’475 patent at claim 19. Just as the term “gastric fluid” itself adopts

differing meanings depending on the context of the claim, so too does “immersion.” As

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noted above, the passage in the specification “ingestion (or immersion in the gastric fluid)” is

susceptible to two readings, which supports a scope of the term covering both environments. 

See Texas Digital Systems, 308 F.3d at 1203 (noting that a term may be construed to

encompass all consistent meanings if more than one definition is consistent with the usage of

the term in the claims). 

Given that two different words are used in the specification and in plaintiff’s proposed

construction to describe non-natural gastric fluid, “simulated” or “artificial” gastric fluid, the

meaning of these terms must be clarified. First, the Court agrees with DepoMed’s assertion

that the two terms are interchangeable. Nothing about the use of the terms in the

specifications indicate they carry any difference in meaning. This is particularly apparent

from the fact that the two terms appear within a single example and refer to the same

solution. ’475 patent at 12:49-67. For simplicity, and following the usage established by

United States Pharmacopeia--the official standards-setting authority for all prescription and

over-the-counter medicines, dietary supplements, and other healthcare products

manufactured and sold in the United States--such non-natural fluids will be referred to as

“simulated gastric fluid.” This term is also construed to include modified formulations of

simulated gastric fluid. As long as the essential characteristics of gastric fluid are embodied

by the fluid, that is, the salinity and pH levels are within the range of what a person of

ordinary skill in the art would expect, then the fluid is within the scope of the claim language.

The Court concludes that the term “gastric fluid” is entitled to a broad construction

that encompasses both the fluid in the human stomach, and any simulated or artificial fluids

recognized by those skilled in the art as a suitable model for the fluid of the human stomach. 

Whether one form of the fluid or the other, or both, applies is to be determined by the context

of the claim. The language of claim 1 of both patents supports a construction of “gastric

fluid” that includes both the fluid of the stomach and simulated gastric fluid. 

C. “about 15:85 to about 80:20”

The disputed phrase “about 15:85 to about 80:20,” which refers to the drug-weight-topolymer-weight ratio of the claimed oral drug dosage form, is found in claim 1 of the ’475

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patent. The Court notes that claim 1 of the ’280 patent recites the same range of ratios but

omits the qualifying word “about” in both instances and therefore is limited to the stated

numerical range. DepoMed asserts that “about” only operates to vary the amount of polymer

in the drug-to-polymer ratio, and calculates a renormalized range of 14.4:85.6 to 80.8:19.2

for this claim limitation. Ivax would construe “about 15:85 to about 80:20” to indicate a

range of 10:90 to 85:15.

There is no mention of the meaning of, or the scope of variation indicated by “about”

in the patent claims, the specification, or any other intrinsic evidence. Although it is rarely

possible to attach a precise limit to “about,” its meaning can usually be understood in light of

the technology embodied in the invention. See Modine Mfg. Co. v. U.S. Int’l Trade

Comm’n, 75 F.3d 1545, 1554 (Fed. Cir. 1996). Thus, the best approach is to determine the

technology-specific facts, and what one of skill in the art would understand a reasonable

range to be. Id.; see also Eiselstein v. Frank, 52 F.3d 1035, 1040 (Fed. Cir. 1995). 

DepoMed’s approach relies on adjusting only the polymer content by 5%, while keeping “the

amount” of the drug the same, and then recalculating the new ratio. For support of such a

narrow construction, DepoMed cites the district court cases of Ranbaxy Laboratories Ltd. v.

Abbott Laboratories, 2005 WL 3050608 (N.D. Ill. Nov. 10, 2005), and Chiron Corp. v.

SourceCF Inc., 431 F. Supp. 2d 1019 (N.D. Cal. 2006). Chiron, however, is readily

distinguished from the present case. In Chiron, the amounts below the lower number of the

range were disclaimed by the patentee, and therefore the lower number was construed to

change only slightly due to the term “about.” See 431 F. Supp. 2d at 1029 (noting the

patentee’s remark that “concentrations below 60 mg/mL were normally ineffective”). The

court held, in the context of the medical method claim at issue, that the term “about”

connoted a variation no larger than the margin of error in a pharmacy professional’s

measuring capabilities. Id. at 1030. Unlike Chiron, the range under consideration here is not

subject to any disclaimer of scope outside the recited range, nor is the margin-of-error

rationale pertinent.

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In Ranbaxy, the court looked to guidance from the FDA as to what range to ascribe to

the term “about” in the phrase “about 5 to about 50% by weight” of the formulation, which

was also for an extended release drug dosage form. Ranbaxy, 2005 WL 3050608, at *12. 

The Ranbaxy court was persuaded that extrinsic guidance, which stated that varying the

amount of polymer more than 5% could have a significant impact on quality and

performance, should control the construction. Id. at *12-13. The Ranbaxy court noted that

even though the regulations address post-approval products, FDA materials were a relevant

source of guidance for those skilled in the art. Id. at *13. 

Here, although the term “about” applies to the drug-to-polymer ratio, the Court agrees

that the term “about” ascribes variance only as to the amount of non-active polymer

component, and not the drug component. First, the patent focuses on the drug delivery

vehicle, and not the amount of drug; therefore, it is reasonable to assume the therapeutic

amount of drug is set according to other considerations, such as the medical needs of a

patient, which are independent of the ’475 patent’s disclosures, and that the patent instead

concentrates on the formulation of “release controlling excipients” of the drug delivery

dosage form. The percentage by weight of drug varies, but only insofar as the amounts of

other components vary. The Court concludes that the variation suggested by the term

“about,” which modifies the drug-to-polymer ratio, only creates variation in the amounts of

those other non-drug components.

The Court also notes that the FDA guidance cited in Ranbaxy is directed specifically

at the subject matter covered in this case, and thus is relevant extrinsic evidence. The FDA

guidance directs that if the additive effect from changes to all release-controlling exipients is

no more than 5% by weight of the total release controlling excipients in the approved

formulation, there is unlikely to be a detectable impact on quality and performance. See

Hopfenberg Opening Decl., Exh. D (Guidance for Industry: SUPAC-MR: Modified Release

Solid Oral Dosage Forms), at 8-10. The FDA further instructs that changes between 5-10%

by weight of total release controlling excipients may have a significant impact on

formulation. Id. at 10-13. For changes in this range, more testing and documentation of the

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modified dosage form is required to maintain compliance. Id. On the basis of such

guidance, compliance with which is mandatory for commercial activity, the Court finds that

one of skill in art would recognize that 5% represents a modest change in the non-drug

components of a drug release dosage form. Such a modest change constitutes a fair reading

of the range understood by the term “about” as it modifies the amount of polymer within a

dosage form. “About” itself implies the amount would be similar to, or not substantially

different from, the amount recited. Here, a reading that the polymer may vary by 5% is

consistent with this definition of “about,” because such a change would not trigger

notification or regulatory compliance activities. 

The Court notes that it is normally improper to rely on industry standards where the

patent specification makes no suggestion that those standards should apply. E-Pass Techs. v.

3COM Corp., 343 F.3d 1364, 1368 (Fed. Cir. 2003). For example, the question considered

in E-Pass was whether a technology standard suggested in the patent itself should be

construed as a limitation on a claim element. Id. at 1367 (noting that the sole question was

whether the term “electronic multi-function card” requires the card to have industry-standard

dimensions). Numerous passages in the written description demonstrated that the

standard-sized card was merely an embodiment and not a definition of the claim scope. Id. at

1369. Unlike E-Pass, which presented the question of whether an industry-standard

embodiment is limiting, this case requires the Court to find a technological basis for

construing the term “about” as someone of ordinary skill in the art would reasonably

understand it. Under these circumstances, it is appropriate to consider extrinsic evidence in

the form of guidance from the FDA, when those practicing in field are compelled to follow it. 

See Modine Mfg., 75 F.3d at 1554. 

The Court finds Ivax’s proffered approach unpersuasive. Ivax contends that the ratios

should be simply adjusted by 5% in either direction--that is, in contends that the term “about”

should expand the ratio by a 5% decrease in the drug and a 5% increase in the polymer, and

vice versa. Ivax supplies no reasoning to support its proffered contruction, other than its

observation that as adjusted the ratios would still describe formulations that fulfill the

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purpose of the invention. By simultaneously adjusting both components, however, this

construction gives rise to significant changes between the relative amounts of drug and

polymer. Such variation is not consistent with the narrow construction that is appropriate to

the circumstances. Most significantly, there is no authority suggesting that one of skill in the

art would adopt such an approach.

 The Court concludes that the term “about 15:85 to about 80:20” requires a narrow

construction that permits variation of the non-active component polymer matrix by up to 5%. 

Therefore, consistent with DepoMed’s proposed construction, the range as modified by the

term “about” is construed to be 14.4:85.6 to 80.8:19.2. 

D. “said polymeric matrix being one that swells upon imbibition of

water thereby attaining a size large enough to promote retention in

the stomach during said fed mode” ’475 patent

“said dosage form being one that when swollen in a dimensionally

unrestricted manner as a result of imbibition of water is of a size

exceeding the pyloric diameter in the fed mode to promote

retention in the stomach during the fed mode” ’280 patent

These disputed limitations appear in claim 1 of the ’475 patent and claim 1 of the ’280

patent, respectively. Both limitations teach that the dosage form must expand and that, upon

expansion, they attain a size sufficient to prevent or inhibit their own passage into the lower

GI tract. The second passage differs from the first due to several amendments made to the

claim language (underlined above), one of which teaches that the dosage form must swell to

“a size exceeding the pyloric diameter.” The Court therefore initially addresses the question

of whether these terms require different constructions. 

DepoMed argues that they do. Based on test results disclosed in the ’389 patent, and

based on evidence about the size of the pyloric diameter, DepoMed proposes that the

polymeric matrix must absorb water to increase to a size exceeding 8 mm under the former

term, and proposes that the polymer size after swelling must exceed 12 mm under the latter

term. Ivax contends that these two limitations should receive the same construction, but

proposes two different ways to construe them. 

The Court agrees that the related limitations of the ’475 and ’280 patents require the

same construction. The Court is unable to identify any aspect of the altered language in the

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’280 patent that demands a substantively different construction. The parties have not

suggested that the reference to a “dosage form,” as opposed to a “polymeric matrix,” makes a

substantial difference. Nor have the parties suggested that the additional language in the

’280 about the swelling of the dosage form “in a dimensionally unrestricted manner” should

lead to a substantively different construction of these two limitations; indeed, the parties have

agreed upon a construction of this term.

Finally, the Court is unpersuaded that the specific language in the ’280 patent

regarding the expansion of the dosage form to “a size exceeding the pyloric diameter”

should render the meaning of that term different in substance from the term in 475 patent,

which refers only more generally to “a size large enough to promote retention in the

stomach.” Indeed, the equivalence of these two phrases is evident from the plain language of

the ’280 patent itself, which suggests that a swollen dosage form must achieve a size

exceeding the pyloric diamete precisely in order to promote its retention in the stomach. 

DepoMed has not offered any evidence about why a polymeric matrix smaller than the

pyloric diameter would promote retention in the stomach. Thus, if the polymer at issue in

claim 1 of the ’475 patent, swollen to Depomed’s preferred size of approximately 8 mm,

would promote retention, it is reasonable to infer that such retention is due to the fact that it

is larger than the pyloric opening. Indeed, the extrinsic evidence cited by DepoMed is

inconsistent with its proposed construction of 12 mm under the ’280 patent; for example, the

study on which DepoMed chiefly relief concludes that the mean pyloric diameter in the fed

mode is 7 mm. See Opening Br. at 13-14 (citing Munk et al.). It is certainly true that factors

other than the size of the pyloric diameter may determine the rate of actual retention. For

example, a pressure gradient within the stomach may actually require a larger sized object to

resist being sent through the pylorus. See Opening Hopfenberg Decl., Exh. J

(Gastrointestinal Transit of Non-Disintegrating Tablets in Fed Subjects) at 115. Yet the

diameter itself would appears to be the minimum size necessary to promote retention. 

Thus, despite the different language in the claims of the ’475 and ’280 patents, it is

not clear that the phrase “large enough to promote retention” means anything different than

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does “exceeding the pyloric diameter.” Indeed, the plain language of the ’280 claim notes

that the size of the swollen dosage form must “exceed” the pyloric diameter, and the claim

thus recognizes that a dosage form larger than the pyloric opening is tantamount to keeping

the dosage form within the stomach. In the Court’s view, this is equivalent to a statement

that a larger size than the opening is necessary to “promote retention.” DepoMed asserts

that the two phrases must have a different meaning because claim 1 of the ’280 patent was

only allowed over claim 1 of the ’475 patent after it was amended to recite this limitation

phrased in terms of the pyloric diameter. This change, however, was not the only one made

to the claim. See supra, Section III (noting additions and deletions to claim 1 of the ’280

patent). The Court concludes that the other amendments to the claim are sufficient to

distinguish the one claim over the other, and the Court is therefore satisfied with a

synonymous construction of these claims, notwithstanding the changes in the language of the

two patents.

The next question is what these two claims mean (accepting, of course, that they mean

the same thing). As to that question, the parties again have competing views. DepoMed

primarily contends that the limitation means that the polymeric matrix absorbs water to

increase to a size exceeding 8 mm. Ivax proposes alternative constructions. First, it suggests

that the claims require the polymer to be only of a size that promotes retention after

imbibition of water--that is, after absorbing water and swelling--but not before. Second, Ivax

suggests that, if a numeric boundary must be determined, then a dosage form will promote

when it is within a range of 2 mm to 20 mm. 

The Court holds that the first construction proposed by Ivax is not correct. Ivax

asserts that the words “thereby attaining” requires the Court to read the claim as meaning

that, absent swelling, the dosage form would not be of a size large enough to promote

retention. Several factors counsel against this conclusion. First, accepting both this

construction would place many of the examples of the patent, in which the smallest

dimension of any dosage form is 6 mm, outside the claim scope. This would be an

undesirable result under well-settled principles of patent law. See Pfizer, 429 F.3d at 1374

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(noting that a claim construction excluding preferred embodiments is “rarely if ever,

correct”). In the same vein, claims dependent on claim 1 recite dosage forms whose size

prior to swelling exceed the size that “promotes retention,” at least as proposed by Ivax. 

Moreover, as a matter of logic, Ivax’s proposed construction is not coherent. The phrase

“thereby attaining” merely implies that a dosage form, post-swelling, must promote retention

within the stomach; in and of itself, this language says nothing of the pre-swelling dosage

form. Both smaller and larger dosage forms may swell and “thereby attain” a size that

promotes retention. Finally, Ivax’s proposed construction also separates the claim language

from the context of the claimed invention. The patents at issue stand in contrast to other drug

dosage forms that release drugs by dissolving--that is, to other dosage forms that become

smaller over time and thereby erode to a size that does not promote retention. The ’475

patent directs that the dosage form will, over time, attain a size that promotes retention. The

claim language relates to the pill’s destination, not its starting point. It is silent about the

starting size of the dosage form, but that silence does not preclude dosage forms that initially

are of sufficient size to promote retention. The Court therefore concludes that Claim 1 also

comprehends starting sizes larger than what would be necessary to promote retention within

the stomach.

Regardless of the starting size of the unswollen dosage form, the crucial question is,

as the plain language of the claim suggests, how large the swollen dosage form must be in

order to “promote retention.” In attempting to answer this question, the Court has examined

both intrinsic and extrinsic evidence submitted by the parties.

For example, the strongest indication of what size is large enough to promote

retention during the fed mode for the polymers of the invention is found in Example 9 of the

’475 patent. Like the sizes used in the prior ’389 patent, pills of either 4 mm or 6 mm were

administered to humans and their retention in the stomach monitored. See ’475 patent at

17:9-24. The results of the experiments demonstrated that pills of both sizes promoted

retention in the stomach in the fed mode: in the fasting mode the tablets were cleared within

30-60 minutes, but in the fed mode 80% of all tablets were retained at 4 hours. Id. The

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specification teaches that the polymer matrix swells, preferably, to a size that is at least about

twice its unswollen volume. Id. at 6:1-2. And although no data about swelling size is

provided in the ’475 patent, the polymers disclosed in the related ’389 patent swelled to

about twice their size in 2-4 hours. The teaching of the ’389 patent thus stands as intrinsic

evidence of what the same inventors recognized about the performance of these types of

polymers and the requirements for gastric retention. Nonetheless, the polymers are not the

same in the two patents, and the specific teaching about the rate of swelling ’389 patent is

only regarded as a preferred behavior in the ’475 patent. See id. at 6:1-2.

DepoMed proposes that a swollen size of 8 mm is appropriate based on the teachings

of the preferred range provided in the ’389 patent, which notes that dosage forms that

promote retention during the fed mode “will normally be in the range of about 2 to about 22

mm, preferably about 8 to about 18 mm.” ’389 patent at 8:34-37. Yet the ’475 patent itself

teaches that “[p]articles exceeding about [10 mm] in size are thus retained in the stomach”

during the fed mode. ’475 patent at 11:67 - 12:1. DepoMed does not make clear why the

full range taught in the earlier patent is not operative in the subsequent patent, nor does it

explain why claim 1 should be construed to apply to an object that is smaller than the one

and only size specifically noted in the patent’s written description.

In the absence of compelling intrinsic or extrinsic evidence indicating that a specific

size would be sufficient to promote retention, the Court concludes that imposing a minimum

on the size of the swollen dosage form necessary to “promote retention” is unwarranted. A

patentee has the right to claim the invention in terms that would be understood by persons of

skill in the art, and “mathematical precision should not be imposed for its own sake.” 

Modine Mfg., 75 F.3d at 1557. A person of skill in the art reading the patent as a whole

would recognize that the claimed polymer matrices must swell upon adsorption of water, and

must not significantly erode throughout the relevant period of immersion in gastric fluid. 

Moreover, a person of skill in the art would recognize that the patent discloses that a tablet of

a given composition and of 4 mm in size would perform as claimed--that is, such a dosage

form attained a size that is “large enough to promote retention” in the subjects that were

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G:\CRBALL\2006\0100\Order -- Claim Construction -- FINAL.wpd 20

studied. See ’475 patent at 17:9-24. From this basic teaching, one of skill in art would

understand both the requirements and the means for testing for compliance with the claim

requirements. The Court declines to impose a more specific construction of the disputed

claim terms, especially since tying the scope of the disputed claim to a minimum size that is

supported primarily by the result from one example would impermissibly read a limitation

into the claims.

In sum, the Court concludes that one of skill in the art would understand that the

limitation “said polymeric matrix being one that swells upon imbibition of water thereby

attaining a size large enough to promote retention in the stomach during said fed mode”

means that the drug dosage form’s polymeric matrix increases in size, and does not erode,

such that when introduced to a stomach in the fed mode, the dosage form remains in the

stomach for several hours.

IT IS SO ORDERED.

Dated: December 20, 2006 

CHARLES R. BREYER

UNITED STATES DISTRICT JUDGE

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