Chemical Patents and Markush Claim Interpretation

Abstract

The construction of patent claim plays critical role as it is central to the evaluation of infringement and validity. A Markush group is a listing of specified alternatives of a group in a patent claim, typically expressed in the form: a member selected from the group consisting of A, B, and C . In Chemical and Biotech Inventions, markush Type claims are used to specify different classes of materials in a step. These types of claims are used as an alternative to define genus of related molecule solely by function. An example of markush claim is given below: A pharmaceutical compound of the formula: A-B-C-D-E Wherein: A is selected from C1-C10 alkyl or alkenyl or cycloalkyl, substituted or unsubstituted aryl or C5-C7 heterocycle having 1-3 heteroatoms selected from O and N; B is selected from C1-C6 alkyl or alkenyl or alkynyl, amino, sulfoxy, C3-C8 ether or thioether; C is selected from C5-C8 saturated or unsaturated heterocycle having 1-4 heteroatoms selected from O, S or N or is a substituted or unsubstituted phenyl; D is selected from B or a C4-C8 carboxylic acid ester or amide; and E is selected from substituted or unsubstituted phenyl, naphthyl, indolyl, pyridyl, or oxazolyl. Markush Claims give rise to a range of problem including sufficiency of disclosure and prior art search. The paper seeks to address such problems associated with markush claims in view of settled principles.