Invalidating a Composition Patent? This is how we did.


The patent under study was related to a cigarette filter having gas adsorbing material and certain specific composition requirements. Our objective was to invalidate the patent for Inter Partes Review.


In patents such as this, which have specific composition requirements, the task of finding prior-art for inter partes review search may become a little difficult, as one might say. But at GreyB, challenges that one might not have yet attempted/accomplished are considered as stepping-stones to success.

With this thought, we started thinking about – How to solve this case?

We started with the basic search to understand the level of availability of required information in the patent literature. We observed that patents disclosing filters with the gas adsorbing material were abundant. However, the specific composition requirements were not being met.

This means we have to first find sources that talk about composition. We found that the academic literature discloses composition information, however, still the level of details that we required were not described in the literature. So what next?

We called all the team members involved in the project and brainstormed on what is something that we have not looked at but may give us some hints. Everyone was allowed to even give wild suggestions so that we do not miss on anything.

In this discussion, we found that every filter (having toxic nature) must undergo some federal agency test procedure. So, it is a possibility that the company would have submitted the test results to the federal government during the approval process. Therefore, some of the other information should be available on the federal agency’s website. That was good enough for us to start moving. So, we explored all such options.

During the search, we found that law in certain countries, such as Canada, makes the company liable to publish the required specific compositions on the cigarette packet. That was a great pointer for us. We purchased all different cigarette packets that were available in Canada so that we can check the composition mentioned on the packet. Similar to as you might have seen compositions mentioned on the food packets or drugs. We also located the private testing facilities which can help us in confirming the required composition in certain filters.

A Checklist to Make Your Life Easy: Download your copy of free Prior Art Search Checklist that helps keeping mistakes at bay:

We actually reversed the whole process. In invalidation search or Inter Partes Review search, most of the people start with finding who did it first, we started with who is doing now. Out of the many companies who are doing it now, there is one who might be the first one to come up with the composition. We were doing all of this with the aim that if the information exists, then the physical boundaries or resource availability should not stop us.

After all the search, we got a lead of a particular company that had a very high probability of using the same composition in its filters. The last part of our search was focused only on that one company. We did a deep dive and finally, identified the relevant document (disclosing filters having gas adsorbing material with the same specific composition information) from the same company, before our priority date. Guess what, the document included all the information that we were looking for.

I hope you might have got an idea by now that we love what we do. Now it may be a pure-play patent invalidation search OR Inter Partes Review search, our objective is – ‘If it exists we will find it’.

Also Read: 3 Instances Where We Invalidated Patents Infringed Under ITC Section 337

Showing 6 comments
  • Stanley D. Schwartz

    Kindly publicly identify the patent in question. I would love to review that patent together with the prior art uncovered. Thanks.

    • GreyB

      Hi Stanley, due to confidentiality agreements, we cannot disclose the patent number in public. However, someone from our team will reach out to you to answer your question.

  • Stanley D. Schwartz

    What commercial databases did you initially use to invalidate the patent?

  • Stanley D. Schwartz

    Better yet, when dealing with the question of patentability or the invalidation of patent claims directed to any special utility composition, which databases do you generally use to meet your clients’ needs? Thanks for your prompt reply.

    • GreyB

      Stanley, In such cases we rely on many databases for example in this specific case we used following –

      Patent Databases
      • Orbit
      • Dialog1
      • Google Patents
      • CIPO (Canadian Intellectual Property Office)
      • STN
      • DPMA (German Patent Office)
      • KIPRIS (Korea Patent Office)
      • SIPO (China Patent Office)
      • IPDL (Japan Patent Office)

      • Google
      • Tobacco Documents Online
      • Google Scholar
      • Legacy Tobacco Document Library
      • PubMed
      • Tobacco Control
      • ScienceDirect
      • Scirus
      • Google Books
      • J-Stage
      • HIghwire
      • Google Scholar Japan
      • Internet Archives
      • PMC
      • Tobacco.org
      • CNKI (China Knowledge Resource Integrated Database)
      • CiNii (Chinese and Japanese Articles)
      • Springer (Online Book Archive)
      • Singapore Library
      • Koreanstudies Information Service System

      Further, in case of patentability search we limit the use of ‘Google’ taking into account the confidentiality of content to be searched.

  • Stanley D. Schwartz

    When dealing with anything chemical, some truly good resources include Chemical Abstracts resources including their databses. Another particularly valuable search tool in the Chemical arts is the U.S. CLAIMS UNITERM Database. Both are invaluable resources for both patentability and validity considerations. Although these are expensive tools to use, they typically will represent a low cost alternative for an otherwise labor-intensive evaluation relating to chemical subject matters.

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