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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Is it acceptable to use ‘optionally’ in patent claims?

Yes, using the term ‘optionally’ in patent claims can be acceptable, but it requires careful consideration. The MPEP 2173.05(h) provides guidance on this: “In Ex parte Cordova, 10 USPQ2d 1949 (Bd. Pat. App. & Inter. 1989) the language ‘containing A, B, and optionally C’ was considered acceptable alternative language because there was no ambiguity as…

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How does the MPEP address negative limitations in patent claims?

The MPEP addresses negative limitations in patent claims in MPEP 2173.05(i), which is closely related to the discussion on alternative limitations in MPEP 2173.05(h). The MPEP states: “The current view of the courts is that there is nothing inherently ambiguous or uncertain about a negative limitation.” This guidance indicates that negative limitations are generally acceptable…

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How does the MPEP address the use of “consisting of” vs. “comprising” in alternative limitations?

The MPEP addresses the use of “consisting of” vs. “comprising” in alternative limitations in MPEP 2173.05(h). The distinction is crucial for the definiteness and scope of the claim: “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.”…

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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 are Markush claims of diminishing scope?

Markush claims of diminishing scope refer to a series of claims where each subsequent claim narrows the scope of the Markush group from the previous claim. The MPEP 2173.05(h) addresses this practice: “The use of Markush claims of diminishing scope should not, in itself, be considered a sufficient basis for objection to or rejection of…

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