Concentration of a Sub-Topically Applied Compound Is Measured at Topical Application

| Shelley Chen Justin J. Gillett


Before Prost, Mayer, and Taranto. Appeal from the United States District Court for the District of Delaware.

Summary: In claims of two patents regarding skin enhancement, the recited concentration of a compound that is applied to sub-topical dermal cells is measured at the point the compound is applied topically to the skin.

The University of Massachusetts (“UMass”) sued L’Oréal alleging infringement of two patents. The asserted patents describe methods of skin enhancement through topical application of compositions containing adenosine. A representative claim recites a concentration of adenosine twice. First, it recites a concentration applied topically to skin: “topically applying to the skin a composition comprising a concentration of adenosine in an amount effective to enhance the condition of the skin, without increasing dermal cell proliferation.” Later, it recites a concentration range applied to sub-topical dermal cells: “wherein the adenosine concentration applied to the dermal cells is 10-4 M to 10-7 M.” The district court issued a claim-construction ruling that the recited concentration range refers to “the concentration as it is applied to the dermal cells,” not as it is applied topically to skin. The district court emphasized that, thus, the first-recited concentration is distinct from the later-recited concentration range. Based on that ruling, L’Oréal moved for summary judgment that the language containing the first-recited concentration is indefinite for failure to establish the claimed concentration. The district court granted the motion and entered final judgment of invalidity against UMass. UMass appealed.

The Federal Circuit reversed the district court’s claim-construction ruling. It held that the recited concentration range refers to the concentration as it is applied topically to skin. The Federal Circuit recognized that the representative claim recites the concentration range “applied to the dermal cells” rather than applied topically to skin. But it reasoned the same concentration can be applied both directly to the skin surface and indirectly to the sub-topical dermal cells. Looking to the specification, the Court identified multiple specific concentrations for “topically administering” adenosine and noted that none specify measuring concentration after seepage through the skin into the dermal cells. Turning to the prosecution history, the Federal Circuit noted the claim language indicating the concentration range “applied to the dermal cells” was added in an amendment. According to the Court, the applicant implied that the amended wording did not change the location where the concentration was to be measured. Based on its new claim construction, the Federal Circuit vacated the district court’s indefiniteness ruling and remanded.

Editor: Paul Stewart