Substituting Equivalents Known for the Same Purpose

As we just learned, combining compounds or materials known in the art to be useful singly for the same purpose can be prima facie obvious. It is also instructive to consider the situation that occurs where one equivalent material or compound is substituted for another in a composition or process. In this context, it is important to not focus solely on the actual equivalence of the material being substituted but also to focus on whether one of ordinary skill in the art would appreciate this equivalency. These points are addressed in the case of Smith v. Hayashi, arising from an interference 

123Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID). 

Count An electrophotographic plate for producing an electrostatic latent image on the 

126A count is a constructive claim used during the interference to define the contested subject matter between the two parties. A phantom count refers to a constructive claim that does not necessarily correspond to a single claim from either subject application but is assembled to capture the subject matter from two substantially similar claims from the two applications. For purposes of the present discussion, we can think of the count as an ordinary patent claim. 

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