Drafting chemical patent applications is an art. Unfortunately, many things, even little things, can be fatal.

Below is short list of things that can be easily dealt with during the drafting process to avoid issues later. This list is intended to inform researchers who are preparing invention disclosures, and assisting patent attorneys and agents in the preparation of chemical patent applications.

The list below is representative, not exhaustive.

#1 - Fail to clearly define the test methods

Generally, new chemical materials are quantitatively characterized by their unique physical or performance properties.

When I'm reviewing a final draft of a patent application, I go through each claim and circle every instance where a unit of measurement is used. I then go back into the body of the application to see if we described how to measure the physical or performance property associated with the unit of measurement.

Unfortunately, many patents claiming new chemical materials having unique properties suffer because (1) the method to measure the property is not described and there is no test method known in the industry, (2) the method to measure the property is not described and there are several conflicting methods known in the industry, or (3) the description of the test protocol is incomplete. I won on an EPO opposition because of no. 3.

Patents lacking in a clear description of critical test protocols results in 3rd parties being unable to test their own materials to determine whether their activities could be deemed infringing. As a matter of public policy, members of the public need to be able to discern whether or not their activities could be deemed to infringe the claims of a patent.

Here in the U.S. we have something called the "Written Description" Requirement. Failure to satisfy this Requirement could result in a USPTO denying the grant of patent, or result in a granted patent later being deemed invalid and unenforceable.

#2 - Relying on test methods having a high margin of error

Not only should patents clearly outline how to measure chemical properties, the test methods should yield relatively reproducible results.

I remember an instance where a patent application claimed an inorganic material having a unique physical property measured by a standard ASTM method. The ASTM protocol actually stated, "This method is not reproducible." The patent office deemed the disclosure to be insufficient, and rejected the application. It was a fatal mistake.

#3 - Fail to properly identify the actual test method used by the Inventors

Inventors often reference 3rd party publications (e.g. journals, patents, ASTM publications) to identify the test methods they used measure a particular property. However, test methods are rarely static.

The following is a common occurrence. While reviewing a 3rd party patent describing a new chemical material having a unique physical property, the property was described as being measured "using the method published by Dr. Z." Problem was, prior to the filing of the patent application, Dr. Z described different and conflicting ways to measure the property at issue. One method put the reviewer outside the claim scope; another put the reviewer inside the claim scope. Fatal.

The same goes with published standardized test methods such as ASTM methods. I've seen patents claiming new chemicals having properties as determined by a particular standard ASTM method, e.g. ASTM E1756 - 08(2015). However, when one looks at the examples where the properties were measured and reported, it's clear the particular ASTM method recited in the claims was not used in the experiments. Older versions of ASTM methods might yield different results than their more current counterparts.

#4 - Use open-ended numerical ranges

A single numerical value is almost never recited in a claim to quantify a unique property for a new chemical (e.g. A cathode material having a capacity of 230.2 mAh/g). Instead, applicants claim a range of numerical values when quantifying chemical properties (e.g. A cathode material having a capacity of between 200 and 300 mAh/g, inclusive).

However, problems arise when open-ended ranges are used (e.g. A cathode material having a capacity of at least 230.2 mAh/g). First, in some countries this is a fatal mistake on its face. Second, if the top or bottom end of an open range is too speculative or unreasonable, an accused infringer will certainly point this out in litigation and argue such values put the claimed invention outside the realm of existing science.

#5 - Fail to define terms

Undefined terms become fodder for arguments during litigation. Terms that may have a clear and ordinary meaning to one chemist may have a different meaning to another.

Terms even as simple as "alkyl" are often defined. If a determination of infringement turns on whether or not the term "alkyl" includes linear but not branched substituents, you can bet both sides will have opposing expert views.

Even failing to define what is meant by a "Group 8" element can be problem during examination. I had a case where an Examiner and I argued over whether Ni is a "Group 8" element (we were both right, but I lost anyways).

The term "substantially" is often used in patents (e.g. wherein the reaction mixture is substantially free of Na). The term is mostly ambiguous. While often used in the U.S., most foreign countries prohibit use of this term. I use the term in my patent applications. However, I provide both a qualitative and quantitative definition for the term.

Disclaimer: This post was prepared by Michael Ross for informational purposes only, and does not constitute legal advice or establish an attorney-client relationship. Readers should discuss their own particular situation with their attorney before taking, or refraining from taking, any action.