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What’s in a chemical claim?

10 May 2021

If you’re reading this article you will probably know that it is a patent claim that defines the monopoly sought. Because of this, it is often regarded as the most important part of a patent application and whilst this may or may not be true, it is certain that the claims are subject to the most scrutiny, both during patent examination and in litigation.

A patent claim can be directed to a product, a method or (in most countries) a use, and all three claim categories can appear in a single claim set, allowing one to protect a variety of aspects of an invention in a single patent application. As such, it is common for a patent attorney to discuss with a client what it is they want to make and sell, and in addition what they want third parties to be prevented from doing, before a claim set is drafted.

Further, if there are a variety of claim-types present the likelihood of catching an infringer is increased.  This becomes increasingly important where infringement actions are brought in more than one country, as different national courts may interpret the claims differently.  As such, a robust claim set would ideally include claims looking at the invention from a range of different angles.

In many respects the chemical field is no different from other technical fields, in that these broad classes of claims can usually be included. For instance, in the chemical field the product may be a new molecular entity, a natural compound that has been isolated for the first time, a composition or formulation (i.e. a new mixture of known components), or a catalyst, to name just a few. Methods of manufacture of new products and also new ways of making existing products can be patented (for instance, where they improve yields). In addition, new uses of known compounds can be patented.

When considering the patentability of compounds, if a compound is already known, for instance as a racemate or in amorphous form, the preparation for the first time of a single enantiomer or a defined polymorph will be regarded as new. The inventive step of such a species will usually depend, however, on whether it has properties which were not predictable based on the known form of the compound.

It is necessary that an invention is enabled by the patent application, i.e. fully disclosed such that at the end of the patent term its teaching can be used by third parties. This means that new molecular entities must be described in terms of preparation methods and recognised analytical characterisation, so that their synthesis can be reproduced. Similarly, if the invention is the isolation of a naturally occurring compound for the first time the isolation method must be provided.

As can be seen, there is flexibility within the patent system to claim different aspects of any invention, and it is important to do so to provide optimal protection.  Further, the chemical field provides scope to protect developments that may not at first seem patentable, so it is always worth discussing any findings with your patent attorney.



Joanna Thurston
Life Sciences & Chemistry group

This publication is a general summary of the law. It should not replace legal advice tailored to your specific circumstances.

© Withers & Rogers LLP May 2021