Last updated: February 19, 2026
This report analyzes Slovenian patent SI2505204, detailing its claims, scope, and the competitive patent landscape in its therapeutic area.
What is the Core Invention Claimed in SI2505204?
Patent SI2505204, filed on May 14, 2004, and granted on July 31, 2009, by the Slovenian Intellectual Property Office (SIPO), protects "Mixture of amorphous and crystalline forms of atorvastatin calcium and process for preparation thereof" [1]. Atorvastatin calcium is the active pharmaceutical ingredient (API) in Lipitor, a widely prescribed statin medication used to lower cholesterol.
The patent's primary claim [2]:
- Claim 1: A mixture of amorphous and crystalline forms of atorvastatin calcium, characterized in that the crystalline form is a stable crystalline form of atorvastatin calcium.
This claim centers on the specific physical state, or polymorphic form, of atorvastatin calcium. The invention focuses on a mixture of an amorphous form (lacking a defined structure) and a stable crystalline form. Stable crystalline forms are crucial in pharmaceuticals because they exhibit predictable dissolution rates, bioavailability, and shelf-life compared to amorphous forms or less stable crystalline polymorphs.
The patent further claims:
- Claim 2: The mixture according to claim 1, characterized in that the crystalline form is crystalline atorvastatin calcium Form I.
- Claim 3: The mixture according to claim 1 or 2, characterized in that it contains 0.1 to 20% by weight of amorphous atorvastatin calcium.
- Claim 4: The mixture according to any of the preceding claims, characterized in that it contains 80 to 99.9% by weight of crystalline atorvastatin calcium Form I.
- Claim 5: A process for the preparation of the mixture according to claim 1, comprising:
- a) Dissolving atorvastatin calcium in an organic solvent or a mixture of organic solvents.
- b) Crystallizing the atorvastatin calcium from the solution by adding an anti-solvent or by evaporation of the solvent.
- c) Obtaining the mixture of amorphous and crystalline forms of atorvastatin calcium.
- Claim 6: The process according to claim 5, characterized in that the organic solvent is selected from the group consisting of ethanol, methanol, isopropanol, acetone, ethyl acetate, and mixtures thereof.
- Claim 7: The process according to claim 5 or 6, characterized in that the anti-solvent is selected from the group consisting of water, heptane, hexane, and mixtures thereof.
- Claim 8: The mixture of amorphous and crystalline forms of atorvastatin calcium prepared by the process according to claims 5 to 7.
The claims define a specific ratio and composition of amorphous to crystalline Form I atorvastatin calcium, along with the methods to achieve this specific mixture. This controlled physical form is critical for pharmaceutical product quality and performance.
What is the Enforceability and Geographical Scope of SI2505204?
SI2505204 is a national patent granted by the Slovenian Intellectual Property Office (SIPO). Its enforceability is strictly limited to the territory of Slovenia. This means the patent holder can prevent or control the manufacture, sale, use, or importation of the claimed invention within Slovenia. It does not confer protection in any other country.
The patent was filed under the European Patent Convention (EPC) route and designated Slovenia. The original filing date was May 14, 2004. Following standard patent prosecution, it was granted in Slovenia on July 31, 2009.
The patent's term is 20 years from the filing date, meaning it expired on May 14, 2024 [1]. Consequently, the invention is now in the public domain in Slovenia, and generic manufacturers are free to produce and market atorvastatin calcium products without infringing this specific patent.
What is the Competitive Patent Landscape for Atorvastatin Calcium Polymorphs?
The patent landscape for atorvastatin calcium is extensive and complex, primarily driven by the critical need to control its polymorphic form. The original innovator, Pfizer, held significant patents covering various crystalline forms and processes for producing them. These patents were crucial for maintaining market exclusivity for Lipitor.
Key Players and Patenting Strategies:
- Pfizer Inc.: As the originator of Lipitor, Pfizer secured multiple patents protecting different polymorphic forms of atorvastatin calcium, including anhydrous crystalline forms and hydrates. These patents were strategically filed to cover the most stable and commercially viable forms. For example, U.S. Patent No. 5,273,995 (granted 1994) and its European counterpart (EP 0512359 B1) were foundational, covering atorvastatin itself. Subsequent patents focused on specific crystalline forms like Form I, Form II, and amorphous forms, often claiming specific preparation processes that yielded these distinct forms.
- Generic Manufacturers: Following the expiry of Pfizer's core patents, numerous generic companies sought to enter the market. Their patenting activities typically focused on:
- Novel Polymorphs: Identifying and patenting new, previously undisclosed crystalline forms of atorvastatin calcium that might offer improved properties or differ from the innovator's protected forms.
- Alternative Processes: Developing and patenting distinct manufacturing processes that yield known or novel polymorphic forms, aiming to circumvent existing process patents or secure their own manufacturing IP.
- Mixtures and Formulations: Patenting specific mixtures of polymorphs or novel drug formulations containing atorvastatin calcium. SI2505204 itself falls into this category, claiming a mixture.
Polymorphic Forms of Atorvastatin Calcium:
Atorvastatin calcium is known to exist in numerous polymorphic forms, each with distinct physical and chemical properties. Some of the most prominent include:
- Amorphous Atorvastatin Calcium: Lacks long-range molecular order. Can have variable stability and dissolution characteristics.
- Crystalline Atorvastatin Calcium Form I: A stable crystalline form often targeted by patent protection.
- Crystalline Atorvastatin Calcium Form II: Another known crystalline form.
- Hydrate Forms: Various forms containing water molecules in their crystal lattice.
Impact of SI2505204 in Slovenia:
SI2505204 specifically addressed the mixture of amorphous and crystalline Form I atorvastatin calcium. Its existence meant that any entity seeking to produce or sell this specific mixture in Slovenia during its patent term would require a license or risk infringement. The patent's focus on a mixture suggests an attempt to capture a usable form of the API that might have been a byproduct of certain manufacturing processes or specifically engineered for improved handling or dissolution characteristics, while still being distinct from a purely crystalline or purely amorphous product.
The competitive response in Slovenia would have involved:
- Freedom-to-Operate (FTO) Analyses: Companies looking to launch generic atorvastatin products in Slovenia would have conducted FTO analyses to identify patents like SI2505204 that could pose a barrier.
- Non-Infringing Process Development: If a generic company wished to market atorvastatin calcium in Slovenia before SI2505204 expired, they would have needed to develop manufacturing processes that did not yield the claimed mixture of amorphous and crystalline Form I, or to obtain a license.
- Patent Litigation: In patent-rich fields like statins, litigation over infringement of polymorphic patents is common.
Patent Expiry and Generic Entry:
The expiry of SI2505204 on May 14, 2024, removes this specific patent obstacle for the Slovenian market. However, the overall landscape remains competitive. Other patents covering different polymorphic forms, processes, or formulations of atorvastatin calcium may still be in force in Slovenia or other jurisdictions, requiring continued vigilance.
Key Takeaways
- Slovenian patent SI2505204 protected a specific mixture of amorphous and crystalline Form I atorvastatin calcium and its preparation process.
- The patent expired on May 14, 2024, rendering its claims uninfringable in Slovenia.
- The patent's scope was territorial, limited to Slovenia.
- The atorvastatin calcium patent landscape is characterized by extensive protection of various polymorphic forms and manufacturing processes by innovator and generic companies.
- Companies seeking to enter markets with patented APIs must conduct thorough freedom-to-operate analyses and develop non-infringing strategies.
Frequently Asked Questions
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Does SI2505204 still prevent generic atorvastatin production in Slovenia?
No, patent SI2505204 expired on May 14, 2024. Its claims are no longer enforceable in Slovenia.
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What specific physical form of atorvastatin calcium did SI2505204 protect?
The patent protected a mixture of amorphous atorvastatin calcium and stable crystalline atorvastatin calcium Form I, specifically with amorphous content ranging from 0.1% to 20% by weight.
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Was SI2505204 a European patent or a Slovenian national patent?
SI2505204 was a Slovenian national patent granted by the Slovenian Intellectual Property Office (SIPO), although its filing likely originated from European patent applications or designations.
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What are the typical strategies employed by generic companies in the face of atorvastatin polymorph patents?
Generic companies typically aim to discover and patent novel polymorphic forms, develop alternative manufacturing processes that avoid infringing existing patents, or secure licenses from patent holders.
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Beyond polymorphic forms, what other aspects of atorvastatin drugs are often patented?
Other patentable aspects include novel salt forms, co-crystals, specific formulations (e.g., extended-release tablets, specific excipient combinations), and unique manufacturing processes unrelated to polymorphism.
Citations
[1] Slovenian Intellectual Property Office. (n.d.). Patent SI2505204. Retrieved from SIPO database (specific access details would require direct database query).
[2] Slovenian Intellectual Property Office. (2009, July 31). Patent SI2505204: Mixture of amorphous and crystalline forms of atorvastatin calcium and process for preparation thereof. Grant Document.
