Opinion ID: 216975
Heading Depth: 3
Heading Rank: 3

Heading: SCD as a Preservative

Text: The district court found that one skilled in the art would not have been motivated to combine Refresh Tears® and Alphagan® because of concerns that SCD would oxidize brimonidine. Apotex challenges that finding by citing an article by Charles P. Thompson entitled Mechanisms of Adrenergic Agonist Induced Allergy Bioactivation and Antigen Formulation. That article, according to Apotex, proves the oxidative stability of brimonidine. In the article, Thompson describes having incubated brimonidine and other α-2 agonists with a hydrogen peroxide-producing species for 120 hours and finding that brimonidine proved stable to the enzymatic oxidation conditions. The district court found the Thompson reference unpersuasive because, among other things, it teaches nothing about the oxidative stability of brimonidine in a Purite®-containing formulation that needs to be shelf-stable for two years. Purite® is Allergan's trade name for an SCD solution. First, Apotex argues that the district court improperly imported a two-year shelf-stability limitation into the claims and used that limitation to avoid the teachings of the prior art. It is true that the claims do not require a particular period of shelf stability, but that was not the only basis for the district court's finding that one skilled in the art would not have expected brimonidine and SCD to be compatible. Dr. Stella, whose testimony was accepted by the court, explained that prior art documents described Purite® as a strong oxidant. Even in light of Thompson's findings, Dr. Stella testified that one skilled in the art would have been extremely hesitant, if not, I would say, directed away from ... formulating brimonidine with a chlorite compound, i.e., Purite®. Apotex challenges Dr. Stella's testimony, contending that it is contradicted by Allergan documents. Apotex points to promotional literature associated with Purite® that describes Purite® as having a relatively low oxidation potential compared to hydrogen peroxide. In response to a question about what it means to describe a component or an excipient as a strong oxidant, Dr. Stella replied that it basically says it's capable of oxidizing drugs, any chemical. When Apotex's attorney asked Dr. Stella about the relative oxidative potentials of hydrogen peroxide and Purite®, Dr. Stella stated that hydrogen peroxide is a strong oxidant and Purite® is a relatively weaker oxidant, but he also stated that Purite® is a very good oxidant. While we recognize that hydrogen peroxide may be a stronger oxidant than the SCD in Purite®, the fact that Allergan touted Purite® as being less reactive than hydrogen peroxide does not establish that one skilled in the art would not have expected SCD to oxidize brimonidine.