How does the “how to make” requirement apply to unstable chemical intermediates?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The “how to make” requirement in patent law is applied differently for unstable and transitory chemical intermediates. As stated in MPEP 2164.01(b):

“Naturally, for unstable and transitory chemical intermediates, the ‘how to make’ requirement does not require that the applicant teach how to make the claimed product in stable, permanent or isolatable form.”

This principle was established in In re Breslow, 616 F.2d 516, 521, 205 USPQ 221, 226 (CCPA 1980). It recognizes that some chemical compounds, by their nature, may not be capable of being made in a stable or isolatable form. In such cases, the enablement requirement is satisfied if the specification teaches how to make the compound in its transient or reactive state, even if it cannot be isolated or made permanent.