Chemical Claims

Polymers present a special problem for patent attorneys. Among other things, a claim to a particular formulation is way too narrow and can almost always be circumvented by simply changing the formula. Fortunately there are two very good strategies for claiming polymers. The first strategy is to claim the polymer by its properties. This is most readily done in a method claim that recites a polymer having the desired characteristics. The following claim was deemed allowable by the PCT (WO 98/13147, "Sublimation Dye Transfer Compositions and Methods", (1998)), but was never pursued in national phase.

A method of imparting an image to a metallic surface, comprising:

providing the surface with a bonding area;

coating the bonding area with a highly cross-linked polymer having a hardness greater than 80elasticity of at least 120% (Shore D, ASTM D2240) and a coefficient of without breaking;

curing the polymeric coating; and sublimating dyes characterizing the image into the coating.

The other strategy is to claim the structure of the polymer as opposed to its chemical composition. This was done very successfully in a series of patents including:

1. A method of fabricating a nanoporous material, comprising:

providing a first polymeric strand and a second polymeric strand, wherein each of the first polymeric strand and the second polymeric strand independently comprises a crosslinking functionality and a thermostable portion, and wherein at least one of the first polymeric strand and the second polymeric strand further comprises a thermolabile portion;

crosslinking the first and second polymeric strands by reacting the crosslinking functionality of the first polymeric strand with the crosslinking functionality of the second polymeric strand, thereby forming a cyclic structure; and

providing an energy to at least partially degrade the thermolabile portion

1. A method of producing a nanoporous composition comprising:

providing a template strand having a plurality of repeating units and a plurality of reactive groups;

reacting at least one of the reactive groups with a modifying molecule, thereby forming at least one crosslinking functionality;

reacting the at least one crosslinking functionality to another crosslinking functionality on a polymeric strand to crosslink the template strand with the polymeric strand, thereby forming a crosslinked polymer, wherein at least one of the modifying molecule and the polymeric strand has a thermolabile group; and

providing sufficient energy to the crosslinked polymer to degrade at least part of the thermolabile group, and thereby producing a void .

1. A method of producing a low dielectric nanoporous material comprising:

providing a first reagent and a second reagent;

mixing the first reagent and the second reagent to form a reagent mixture; forming a polymeric structure from the reagent mixture; and

removing at least part of the second reagent from the polymeric structure by a method other than thermolysis, and other than evaporation, wherein the second reagent does not comprise a fullerene .

Pharmaceutical and other chemical inventions are quite easy to claim, so long as the chemical entities are novel. In that case an applicant can simply claim the structure and its variants. Problems arise, however, when the compound is old. In that case there are several alternative claiming strategies, including claiming a new use, a precursor, a new dosage form or regimen, a new route of administration, or a combination with some other drug, excipients and so forth. Note that claiming a metabolite of a drug doesn't usually work because the metabolite is deemed to be inherent in the compound .

It is even possible to claim a pharmaceutical where the compound is old, the use of the drug for the disease is old, and the formulation is old.

1. A method of modulating Th1 and Th2 response in activated T cells of a human patient comprising administering Ribavirin to the T cells in a dosage which promotes the Th1 response and suppresses the Th2 response .

1. A method of inversely modulating Type 1 and Type 2 responses of lymphocytes contained within an environment by adding ribavirin to the lymphocytes in a concentration which increases the Type 1 response and suppresses the Type 2 response .

17. A composition comprising interferon gamma or an interferon gamma-inducing compound in an amount that is determined to be effective to increase activity of at least one component of a proteasome or guanylate binding protein and to thereby elicit a non-cytolytic reduction of viral propagation in a hepatocyte infected with HCV .

In difficult cases one should consider claiming upstream or downstream aspects of the combination of interest. For example, when claiming an old drug for a new use, it is probably not possible to claim the drug as a chemical composition. Yes, one could try claiming a different dosage regimen or dosage form, but those may already be known, or be obvious. For example, if a drug is already known in 25 mg tablets, and prescribed at 75 mg/day (tid), the patent office will not be particularly happy about granting a claim to a dosing of only 25 mg/day. And claiming a new use per se might be patentable, but would be very difficult to enforce. The current manufacturers would simply say that they are producing the drug for the old off-patent uses, and the physicians can't be sued for simply prescribing the medication.

The answer may be to determine whether the lower dosage results in a new metabolite profile (a downstream aspect). In that case one could claim giving a drug (any drug) that produces the new metabolite profile. Since the higher (known) dose would produce another profile, and presumably no one in the prior art ever saw the new profile, the claim might well be both patentable and enforceable. Similarly, from a manufacturing standpoint, one can sometimes claim slightly different strategies or components (upstream aspects) required when shifting from low volume to high volume production.