Pharmaceutical companies invest huge dollars in R&D, production and marketing of any newly developed drug . As law, the patent term is 20 years, but it is roughly 16-18 years in case of drug patents, as they have to pass the FDA regulations, before coming in markets. When the patent expires, generic companies come up with the generic version of the same drug and sale in the market with very low price. Thus, to be in the competition, innovator companies try to extend the drug life time. This is known as extension of the known drug for longer time protection. That's the reason any specific drug is not protected by one particular patent, instead it is covered by different patents, including the blocking patents. Patents do not protect drugs as such, but "inventions".
A better understanding of different types of pharmaceutical patents and ways to extend the life time of the drug patents is essential for the patent professionals involved in pharmaceutical research. The drug patents can be broadly classified into following categories:
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Composition
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Formulations
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Product form
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Drug release
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Compound
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New chemical entity
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Physical form
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Particle size
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Selection patents
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Active metabolites
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Prodrugs
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Dosage/dose
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Method or process
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Use or application
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Drug delivery
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Devices
1) Compositions
Composition patents, discloses combination of one or more than active ingredients (known or novel) and pharmaceutically acceptable carriers or excipients, such as solvents, buffers, fillers, binders, desintegrants and lubricants. The inventiveness of these patents is in the selected combination of molecules and their specific new function application.
In India, a novel pharmaceutical composition with a single active ingredient (whether known or novel) with an inert carrier is not patentable, as there is no synergy between the components viz. the active compound and the inert carrier.
2) Formulation
A formulation patent relates to the preparation of particular composition in any specific desired form for better effect, form or release.
2.1) Product form: It relates to the different dosage form of new or already known drug or pharmaceutical composition having better active drug release method. The same active ingredient may be formulated in different forms, example, as tablets, capsules or aqueous solutions for parenteral administration. For example, an anti-inflammatory cream containing A would be regarded as clearly distinct from a tablet containing "A" for controlling diabetes. The cream is new because "A" has never been formulated in this form before, and it would be inventive if the previous use of "A" would not suggest its use in topical form."
2.2) Drug release: In some patents, the claimed formulation is associated with certain effects, such as controlled release in blood of a drug . Other drug release methods include timed, extended and slow release .
3) Compound
These patents related to identification of new chemical, biological, herbal or drug molecule. Patent may or may not say anything about the composition (when added with other ingredients), application or use of the said molecules. In most cases, these new molecules are represented by different formulas in the claim (Markush claims). These compounds can be either new molecules form some sources (e.g., biological, herbal) or new chemical entity (NCE). It can be further categorized based on nature of compound, i.e., polymorph, isomers, physical forms (crystalline or amorphous) or salts.
3.1) New chemical entity: A new chemical entity (NCE) is generally represented by Markush structures in patent claims and discloses different chemical formulas and derivates of novel drugs .
3.2) Physical form: Polymorphism and enantiomerism property of the chemical compounds are exploited by the pharma companies to extent the drug life cycle by inventive new polymorphs, isomers, physical forms (crystalline or amorphous), enantiomers of the know drug.
3.3) Particle size: The dissolution rate of a drug is a function of its intrinsic solubility and its particle size. Particle size reduction can lead to an increased rate of dissolution and higher bioavailability, thus a lot of patents in pharmaceutical industries related to composition with specific particle size of the ingredients, along with dosage forms (e.g., suspensions or dispersions).
3.4) Selection patents: In a 'selection patent' claims a single element or a small segment within a large known group is 'selected' and independently claimed based on a particular feature not mentioned in the large group. For example, patent on a specific range (e.g., C3-C12) is claimed if a chemical having n-carbon atoms is already patented.
3.5) Active metabolites: In some cases, patents focuses on a compound and on the active metabolite that produces the desired effect in the body. It produces the same effect as the parent drug compound.
3.6) Prodrugs: When metabolised in the body, inactive compounds (called 'prodrugs') can produce a therapeutically active ingredient. Some patent claims cover a drug and its prodrug/s.
4) Dosage/dose
Some patent documents claim inventions consisting of the dosage form for administration (e.g., solid dosage form for oral administration) to patients of an existing product. These claims are normally equivalent to claims over methods for medical treatment, as the subject matter is not a product or process but the way in which a product is therapeutically used.
5) Method or process
These patents discloses the method or process to manufacture or preparing, either a compound or composition. They in most case also disclose the application of the said compound or composition. Another type of patents in this category is method of identification of new molecules, method of treatment, method of screening or diagnosis. These patents also include the different assays methods.
6) Use or application
The focus of this kind of patents is on the effect of compound or composition on a human body or other subjects, for example, treatment and prevention of from specific diseases),
7) Drug delivery
These patents either disclose any method or device or system for delivering the drug into the human body. It includes both the general drug delivery and the targeted drug delivery system or methods.
7) Devices
It includes patents which disclosed any device, apparatus, kit or sometimes system for the drug delivery, manufacturing, monitoring, screening or diagnosis of particular drug and its activity.
Conclusion It is a myth among patent analyst, that reading and understanding rug patent is tough. It's true, but if you have clear knowledge about different patent types, drug formulations and basic terminologies used in the pharmaceutical patents, it will make your life easy. Careful reading of patent claims to identify the novelty and inventiveness along with title and abstract can provide high level information about the any patent.