What is a Markush group in patent claims?

A Markush group is a claim construction that lists alternatives to define a limitation in a patent claim. As stated in the MPEP 2173.05(h): “Claims that set forth a list of alternatives from which a selection is to be made are typically referred to as Markush claims, after the appellant in Ex parte Markush, 1925…

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What is a Markush group in a patent claim?

A Markush group is a way of claiming a list of alternatively useable members in a patent claim. According to MPEP 2173.05(h): “A Markush grouping is a closed group of alternatives, i.e., the selection is made from a group ‘consisting of’ (rather than ‘comprising’ or ‘including’) the alternative members.” Markush groups are typically used to…

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Can a Markush group in a patent claim be indefinite?

Yes, a Markush group in a patent claim can be indefinite under certain circumstances. The MPEP 2173.05(h) states: “In certain circumstances, however, a Markush group may be so expansive that persons skilled in the art cannot determine the metes and bounds of the claimed invention. For example, if a claim defines a chemical compound using…

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What is the difference between ‘consisting of’ and ‘comprising’ in Markush groups?

The choice between ‘consisting of’ and ‘comprising’ in Markush groups is crucial as it affects the scope of the claim. According to the MPEP 2173.05(h): “A Markush grouping is a closed group of alternatives, i.e., the selection is made from a group ‘consisting of’ (rather than ‘comprising’ or ‘including’) the alternative members.” ‘Consisting of’ creates…

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