Assessment of unity of invention

Intermediate and final products

6.69 In some cases claims will be directed towards novel intermediates that are used for the preparation of the final products of the invention. There are special rules that apply in such cases and these are set out in the PCT Guidelines.

6.70 Unity of invention is considered to be present in the context of intermediate and final products where the following two conditions are fulfilled:

(A) the intermediate and final products have the same essential structural element, in that:

(1) the basic chemical structures of the intermediate and the final products are the same, or
(2) the chemical structures of the two products are technically closely interrelated, the intermediate incorporating an essential structural element into the final product, and

(B) the intermediate and final products are technically interrelated, this meaning that the final product is manufactured directly from the intermediate or is separate from it by a small number of intermediates all containing the same essential structural element.

6.71 Unity may exist between different intermediates provided the different intermediates collectively satisfy the above requirements. However, if two different intermediates incorporate a different structural element into the final product, they will not meet the above requirements. A simple example of this is in the following multi-step reaction:


Assuming A, B and C are not relatively simple structural units, the claims are as follows:

1. Compounds having formula A – B – C
2. Compounds having formula A – B
3. Compounds having formula A
4. Compounds having formula C

In this case Claims 1 to 3 would have unity. Compounds of these claims have the same structural element A, and providing this is a relatively significant essential element that is related to the activity of the final compounds, this group of inventions would meet the requirements, taking guidance from the PCT Guidelines.

On the other hand there would not be unity between Claims 3 and 4 since these do not incorporate the same structural element into the final compound. Accordingly, the claims could be divided into two possible groups: Invention 1 comprising Claims 1 to 3, and Invention 2, comprising Claim 1 and Claim 4.

6.72 Other considerations set out in the PCT Guidelines are as follows, but it should be noted that in all cases a pragmatic approach should be adopted as to whether or not a unity objection should be taken:

(a) The intermediate and final products should not be separated inthe process by a known compound (in which case the inventive concept of the  intermediate would lie in the preparation of the known intermediate rather than the novel final product).

(b) It is possible for a compound to be claimed as an intermediate in the preparation of a final product and to also have other uses. The claims could be drafted in that case to define the final products, and/or compositions containing such, their preparation and their use, as well as claims to the novel intermediates and their preparation and use.

(c) If the intermediate and final products are families of compounds, each intermediate compound must correspond to a compound claimed in the family of the final products. However, some of the final products may have no corresponding compound in the family of the intermediate products so that the two families need not be absolutely congruent.

6.73 The intermediate may have the same use as the final product, or it may have any other use. Any other use of this intermediate may be considered a further invention. Furthermore, the final product should be manufactured directly from the intermediate or from the intermediate via a small number of other intermediates having similar structure.