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Mar 22, 2006


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In the Kao case, with a 2% salt addition, wasn't some of the polymer in the acid form and some in the salt form? If so, why not an infringement of the patent. I can accept that salts are different from acids and possilibty leading to an improvement and patentability? But, that shouldn't be a bar to infringement.


I'm a little confused. Acid + Base --> Salt + Water applies only to Bronstead acid/bases. The substituted amino base here is a Lewis base so I'm not even sure that a salt is being formed.

I'm a chemist, not a lawyer, but I understand that you are your own lexicographer when writing a patent, so it may not be technically correct but legally correct.

I also have to admit that I have only read the summary written by Bradley and not the patents or the opinion.

John Spevacek
Aspen Research, -
“Turning Questions into Answers”

Opinions expressed herein are my own and may not represent those of my employer.

My first reaction to reading this case was incredulous. How can 2% by weight of AMP (a base) consume 98% by weight PVM/MA copolymer (an acid) to leave no residual acid? The claim clearly states that the patented compound is to "comprise", in an amount effective to remove keratotic plugs, "a poly (alkyl vinyl ether/maleic acid) copolymer".

Then I read the judgment and saw that this may have been an attorney's error at trial. The CAFC states that KOA's argument that the acid was not fully neutralized by the base was "unsupported by the record or any other authority." So much for relying on common general knowledge, including judicial awareness of basic high school chemistry.

The other disturbing aspect of the CAFC ruling is the implication that because KAO applied for a subsequent improvement patent in which the salt was the active ingredient, this implied that the earlier patent in suit was intended to cover exclusively an acid. This suggests that it is dangerous to file for an improvement invention for fear that this will be used to read-down an earlier dominant patent claim.

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