Legal Definitions - Markush group

A Markush group is a specific way to describe a component or ingredient in a patent claim when several different, but functionally equivalent, options could be used. Instead of listing every single possible variation, a patent applicant can define a group of alternatives, stating that a particular part of their invention can be chosen from this defined list. The crucial requirement is that all members of the Markush group must share a significant common property or characteristic that allows them to perform the same essential function within the invention being claimed. This allows the patent to cover a range of similar solutions without having to claim each one individually, as long as they all achieve the same intended result in the invention.

Here are some examples illustrating the concept of a Markush group:

• Example 1: Pharmaceutical Formulation

  Imagine a patent application for a new medication designed to treat a specific type of allergy. The patent claim might state: "The antihistamine component of the pharmaceutical composition is selected from the group consisting of loratadine, fexofenadine, and cetirizine."

  How it illustrates the term: Loratadine, fexofenadine, and cetirizine are distinct chemical compounds. However, they all share the common property of being non-drowsy antihistamines, meaning they perform the same essential function of blocking histamine receptors to alleviate allergy symptoms. Therefore, any of these three could be used interchangeably as the antihistamine component in the claimed medication, making them suitable for a Markush group.

• Example 2: Industrial Adhesive Composition

  Consider a patent for a novel industrial adhesive designed for high-temperature applications. A claim might specify: "The curing agent for the adhesive is selected from the group consisting of dicyandiamide, imidazole, and an aromatic amine."

  How it illustrates the term: Dicyandiamide, imidazole, and various aromatic amines are different chemical substances. Despite their structural differences, they all possess the common property of acting as effective curing agents for the adhesive resin, enabling it to harden and achieve its desired strength under high temperatures. They are functionally equivalent in this specific role within the adhesive composition.

• Example 3: Water Filtration System

  A patent application describes an improved water filtration system for removing heavy metals. One claim might read: "The heavy metal adsorbent material is selected from the group consisting of activated carbon, zeolite, and ion-exchange resin."

  How it illustrates the term: Activated carbon, zeolite, and ion-exchange resin are distinct materials with different chemical structures and mechanisms of action. However, they all share the common property of being effective adsorbents for heavy metals in water. Each material can perform the same function of removing contaminants from the water, making them suitable members of a Markush group for this filtration system.