Opinion ID: 772063
Heading Depth: 3
Heading Rank: 2

Heading: Based on the Dry Weight

Text: 25 Abbott argues that the district court erred in its construction of the expression based on the dry weight as meaning that the weight of the lung surfactant extract material is measured before it is combined with a pharmaceutical carrier. Abbott urges that that expression, according to one of skill in the art, means that a liquid suspension or solution may be tested on a dry weight basis by first drying the material and then assaying the solid components of that dried material by percentage. 26 ONY responds that water is a component of the surface active material to be measured like any other, and that the district court did not err in requiring that the surface active material be measured in the dry state before it is combined with physiological saline to form a pharmaceutical composition. 27 We agree with ONY that the expression based on dry weight means based on the dry weight of the surface active material before it is combined with a carrier to form a pharmaceutical composition. The surface active material may be part of a pharmaceutical composition, but it is a distinct component of that composition and must be evaluated independently of the pharmaceutical composition in order to determine if it meets the claim limitations to surface active material. 28 Abbott's proposed construction impermissibly ignores the claimed water percentages. The specification and the claims set forth without ambiguity that the surface active material must have specific, measurable percentages of water, presumably the residual water remaining in the material after lyophilizing (i.e., freeze-drying) a purified solid residue suspended in distilled water, which is the final synthetic step in the preparation of the surface active material. See, e.g., '301 patent, col. 10, ll. 45-57; col. 12, ll. 2-8; '839 patent, col. 12, ll. 57-66. The patentee defined the residual water to be that measured by a method such as the Karl Fischer method, and present in the specifically claimed percentages. The extrinsic evidence of what would be understood by someone of skill in the art -- that water is an irrelevant reference point -- contradicts the express requirement of the claims and the description in the specification that water is a relevant and measurable ingredient. We consider extrinsic evidence, such as how a skilled artisan would interpret the expression based on dry weight, only when it helps the court come to a proper understanding of the claims; it may not be used to vary or contradict the claim language. Vitronics, 90 F.3d at 1584, 39 USPQ2d at 1578. We therefore conclude that the expression based on the dry weight means based on the dry weight of the surface active material before it is combined with a carrier, and that this phrase does not negate the claim limitations to water.