Issue 192 | May 3, 2004
Novartis Pharmaceuticals Corp.
v. Eon Labs Mfg, Inc.


  • Patent Claim Construction: Ambiguity was found in a patent claim, requiring resort to the specification and prosecution history to resolve its meaning, because the dictionary definition of the claim term “hydrosol” referred to a “sol,” the dictionary definition of a “sol” referred to a “solution,” and the dictionary definition of a “solution” was found to be ambiguous.
  • 35 USC 271: Infringement of a composition claim: A claim directed to a hydrosol composition was not infringed by a hydrosol formed in the patient’s stomach as the result of ingesting a non-hydrosol form of a drug.


The Federal Circuit affirmed the final judgment of the district court granting Eon a summary judgment of non-infringement of the ’382 patent.

The ’382 patent concerns a problem with administration of cyclosporin, an immunosuppressant drug. Because it is not very soluble in water, cyclosporin is difficult to administer in a formulation that will be readily absorbed by the aqueous environment of the human body.

Novartis addressed this problem by discovering and patenting (in the ‘382 patent) a hydrosol formulation for cyclosporin. A hydrosol is an aqueous dispersion of very small solid particles of the drug that are more readily absorbed by the body. In addition, a stabilizing compound is added to keep those small solid particles from growing larger. Claim 1 is representative:

1. A hydrosol which comprises solid particles of a cyclosporin and a stabilizer which maintains the size distribution of said particles, wherein said cyclosporin has a water solubility below 0.5 grams per 100 milliliters, and said particles have a weight ratio of cyclosporin to water of about 1:300 to about 1:1500 and a weight ratio of cyclosporin to said stabilizer of about 1:1 to about 1:50.

Eon manufactures capsules that contain cyclosporin dissolved in a small amount of ethanol. Because there is no water in these capsules, and the cyclosporin inside is completely dissolved, the mixture contained in Eon’s capsules is not a hydrosol. However, Novartis contended that when one of Eon’s capsules is ingested an infringing hydrosol is formed in the aqueous environment of the user’s stomach. Novartis therefore sued Eon for indirect infringement of the ’382 patent arising from the use of its capsules.

The district court construed “hydrosol” to exclude a dispersion of solid particles of cyclosporin which only forms in the stomach of a patient. The district court granted summary judgment against Novartis, holding that there was no direct infringement, either literally or under the doctrine of equivalents. The Federal Circuit majority affirmed.

The key issue on appeal was whether “hydrosol” as it appears in all of the ’382 patent claims is limited to medicinal products prepared outside of the body or whether it also includes products formed within the stomach of a patient after a particular medicinal product has been ingested.

Neither party suggested that “hydrosol” has a specialized meaning inconsistent with the ordinary dictionary definition, so the Federal Circuit began its analysis with dictionary definitions.

Webster’s Third New International Dictionary defines:

the term “hydrosol” as “a sol in which the liquid is water,”

a “sol” as “a dispersion of solid particles in a liquid colloidal solution,”

a “solution” as either “(1): a liquid containing a dissolved substance” or “(2): a liquid and usu. aqueous medicinal preparation with the solid ingredients soluble” (establishing a dichotomy, according to the majority) and,

medicinal” as “of or relating to medicine.”

Medical dictionaries define “preparation” in terms of a substance that is made prior to being administered.

The definition of “preparation,” incorporated in the second definition of “solution,” was taken by the majority to mean that the hydrosol must be made outside the human body, before being administered, to meet the second definition of “solution.”

The majority’s analysis of the dictionary definition of “hydrosol” therefore yielded two possible meanings, based on two competing definitions of a “solution.” The claim term “hydrosol” could either be (1) broadly defined to include a dispersion of solid particles in aqueous colloidal solution formed in a patient’s stomach, in view of the first definition of a “solution,” or (2) limited to a medicinal preparation consisting of a dispersion of solid particles in an aqueous colloidal solution formed outside the body before being administered, according to the second definition of a “solution.”

The Federal Circuit determined that the specification and prosecution history clearly describe the claimed hydrosol only as a pharmaceutical composition, and make no mention of the term in any other context. Since the dictionary defines “pharmaceutical” as a medicinal drug, these descriptions were found by the majority to support adoption of the narrower definition of a solution as a medicinal preparation.

The prosecution history of the ’382 patent was found to point to the same conclusion. Novartis distinguished the prior art by emphasizing the advantages of its invention as an injectable hydrosol . The Federal Circuit noted that an injectable material is always made up outside the body before use.

Having concluded that “hydrosol” as used in the ’382 patent is limited to an aqueous medicinal preparation prepared outside the body, the majority found no direct infringement of the ’382 patent. There can be no induced or contributory infringement without an underlying direct infringement.

The Federal Circuit majority also held that the formation of a particulate dispersion inside the body cannot infringe under the doctrine of equivalents because this would vitiate the claimed requirement that the dispersion be prepared outside the body. Consequently, the district court did not err in granting summary judgment of non-infringement under the doctrine of equivalents.

Judge Clevenger dissented. He reasoned that Novartis was denied the ordinary meaning of “hydrosol,” which of course is not restricted to hydrosols made in any particular place, whether in a factory or in a human stomach.

According to Judge Clevenger, the majority over-used the dictionary, finding an ambiguity in the term "solution" not used in the claims. The claims use the term “hydrosol.” The majority should have noticed the error of its ways because the definition it adopts for "solution" requires that the solid ingredients be soluble. The purpose of the claimed hydrosol is to address the problem of cyclosporin's insolubility. The claimed hydrosol is not a "medicinal preparation with the solid ingredients soluble," and the preferred definition of "solution" cannot be tied back to the claim language. When such a disconnect occurs in the dictionary pathway, the dictionary exercise has gone too far.

Judge Clevenger stated that the majority should have ended its dictionary analysis at the word "hydrosol." Only by pressing on through several degrees of separation can the majority get to the definition of "medicine" on which it relies to confirm the existence of a second competing pertinent definition of "hydrosol." Dictionaries are fine tools to assist in the exercise of claim interpretation, but in this case the majority has simply overworked the dictionaries to the point of error.

Finally, Federal Circuit case law has long recognized that medicines claimed in patents can be made inside or outside the body, and that infringement will lie in either case if the proper proofs are made. Judge Clevenger stated that Novartis' patent should not be limited to injectable hydrosols of cyclosporin made outside the body. Novartis is entitled to a trial in which it can bring forward its proof of infringement.

To view the full case, visit http://www.aplf.org/mailer/Issue192.doc.

Please e-mail George Wheeler of McAndrews, Held & Malloy, Ltd. at gwheeler@mhmlaw.com with any questions that you might have about this case.

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