Reciting Ranges in Chemical Patent Applications and The 112 Rejection

MARK TERRY, ESQ.

Ex Parte Moraes Barros considered whether a patent specification that disclosed a broad numerical range supported an amended claim reciting a narrower range within it.

The examiner rejected the narrower range under the written-description requirement of 35 U.S.C. § 112 because that exact subrange had not been expressly stated in the original specification.

The Board explained that an originally disclosed broader range may support a narrower range even when the narrower range was not explicitly listed. A range can serve as shorthand for the discrete points it encompasses, although written-description questions remain dependent on the facts of each case.

Lessons learned: Chemical applications need not necessarily list every possible subrange. A carefully drafted disclosure of a broader range may provide adequate support for later claims to a narrower range contained within it.