What makes a Markush grouping proper?

A Markush grouping is considered proper if the members of the group share both:

1. A “single structural similarity”
2. A common use

This requirement can be met in two ways:

1. The alternatives are all members of the same recognized physical or chemical class or the same art-recognized class, and are disclosed in the specification or known in the art to be functionally equivalent and have a common use.
2. The alternatives share both a substantial structural feature and a common use that flows from the substantial structural feature.

As stated in the MPEP: A Markush grouping is proper if the members of a group share a single structural similarity and a common use. See subsections II – IV, below, for guidelines regarding the determination of whether a Markush grouping is improper.

To learn more:

• Markush grouping
• proper Markush claim
• patent claim requirements