General Principles and Object of Claims:
Claims are considered to be the most important part of a patent document. In a complete specification the description is followed by the Statement of Claims. Since the claims constitute the legal part for claiming the protection of the patent rights, the construction of same plays a critical role as it is central to the evaluation of infringement and validity.
The "Markush" claim is a special drafting manner for claims in the field of Chemical and Biotech Inventions, which was first successfully used by the inventor Eugene Markush in a US patent in 1920, post which claims of this kind are named after his family name.
A Markush claim refers to a chemical structure by means of symbols indicating substituent groups. In such a claim, one or more parts of the claimed compound comprise multiple functionally equivalent chemical entities.
Example 1: "The process for the manufacture of dyes which comprise coupling with a halogen substituted pyrazolone, a di-azotized unsulphonated material selected from the group consisting of aniline, homologues of aniline and halogen substitution products of aniline."
Example 2: "A pharmaceutical compound of the formula: A—B—C—D—E Wherein:
A is selected from C1–C10 alkyl or alkenyl or cycloalkyl, substituted or unsubstituted aryl or C5– C7 heterocycle having 1–3 heteroatoms selected from O and N;
B is selected from C1–C6 alkyl or alkenyl or alkynyl, amino, sulfoxy, C3–C8 ether or thioether;
C is selected from C5–C8 saturated or unsaturated heterocycle having 1–4 heteroatoms selected from O, S or N or is a substituted or unsubstituted phenyl;
D is selected from B or a C4–C8 carboxylic acid ester or amide; and
E is selected from substitute d or unsubstituted phenyl or naphthyl, indolyl, pyridyl, or oxazolyl"
With chemical structures, it is often possible to use many substituents in a given structure. The result is that you may have a few-ranging-to-hundreds of possible formulations; and each possible substitution location could be a different substituent. There are often changes in the substituent groups that do not change the original use of the compound and, thus, can be thought of as part of the original invention.
34Markush type claims allow important innovations to be patented. For example, when a new organic compound, that has a novel structure never obtained before, is invented and can have many possible substituents that could be used, one can effectively group these possible substituents in a Markush type of claims. So, one can claim the basic structure along with substituents like halogens, alcohols, hydrocarbons, etc. However, such group of compounds are allowable when supported by a single and definitive process.
Footnote
34 http://www.ipindia.nic.in/writereaddata/Portal/IPOGuidelinesManuals/1_59_1_15-wo-ga-34-china.pdf
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
