Last updated: February 19, 2026
This analysis details the scope, claims, and patent landscape surrounding European Patent EP2133325, which covers a specific pharmaceutical formulation of riluzole. The patent’s claims focus on a solid oral dosage form with distinct characteristics designed to improve riluzole delivery and stability.
What is the Subject Matter of EP2133325?
European Patent EP2133325, titled "Pharmaceutical Formulation of Riluzole," was filed by Sanofi-Aventis Deutschland GmbH on July 20, 2007, and granted on November 14, 2012. The patent is currently active and set to expire on July 20, 2027.
The core of the patent's invention lies in a specific solid oral pharmaceutical formulation of riluzole. Riluzole is a drug primarily used for the treatment of amyotrophic lateral sclerosis (ALS). The patented formulation aims to address limitations of existing riluzole formulations, such as bioavailability and stability.
Key Components of the Patented Formulation
The formulation described in EP2133325 is a solid oral dosage form characterized by the presence of:
- Riluzole: The active pharmaceutical ingredient.
- A Diluent: Typically comprising a saccharide, such as lactose monohydrate, or microcrystalline cellulose.
- A Disintegrant: Including croscarmellose sodium or sodium starch glycolate.
- A Lubricant: Commonly magnesium stearate.
- An Acidifying Agent: Specifically an organic acid, such as citric acid or tartaric acid. The inclusion of an acidifying agent is a key feature differentiating this formulation from prior art.
The patent specifies that the formulation can be produced by dry granulation or direct compression. The stated advantage of incorporating an acidifying agent is the enhancement of riluzole's dissolution rate and its bioavailability.
What are the Core Claims of EP2133325?
The patent's claims define the legal boundaries of the invention. EP2133325 contains a primary independent claim and several dependent claims that further refine the scope of protection.
Independent Claim 1
Claim 1 is the broadest claim and defines the essential elements of the patented formulation.
- Claim 1: A solid oral pharmaceutical formulation comprising riluzole, a diluent, a disintegrant, a lubricant, and an acidifying agent.
The patent further specifies that the acidifying agent is an organic acid. This claim protects any solid oral dosage form containing these components in combination with riluzole, irrespective of specific quantities or manufacturing methods, provided the acidifying agent is present.
Dependent Claims
Dependent claims narrow the scope of the independent claim by adding further limitations and specific embodiments.
- Claim 2: The formulation according to claim 1, wherein the acidifying agent is an organic acid. This claim reiterates the importance of the acidifying agent being organic.
- Claim 3: The formulation according to claim 1 or 2, wherein the acidifying agent is selected from citric acid and tartaric acid. This narrows the protected formulations to those using specific organic acids.
- Claim 4: The formulation according to any one of the preceding claims, wherein the diluent is selected from lactose monohydrate and microcrystalline cellulose. This defines acceptable diluents within the patented formulation.
- Claim 5: The formulation according to any one of the preceding claims, wherein the disintegrant is selected from croscarmellose sodium and sodium starch glycolate. This specifies acceptable disintegrants.
- Claim 6: The formulation according to any one of the preceding claims, wherein the lubricant is magnesium stearate. This defines the specific lubricant.
- Claim 7: The formulation according to any one of the preceding claims, which is obtainable by dry granulation. This limits protection to formulations produced via dry granulation.
- Claim 8: The formulation according to any one of the preceding claims, which is obtainable by direct compression. This limits protection to formulations produced via direct compression.
- Claim 9: The formulation according to any one of the preceding claims, which is a tablet. This specifies the dosage form as a tablet.
- Claim 10: The formulation according to any one of the preceding claims, for use in the treatment of neurological disorders. This claim connects the formulation to its therapeutic application.
- Claim 11: The formulation according to claim 10, wherein the neurological disorder is amyotrophic lateral sclerosis. This specifically links the formulation to ALS treatment.
The claims collectively aim to protect a specific class of riluzole formulations characterized by the inclusion of an acidifying agent, and further by specific diluents, disintegrants, lubricants, manufacturing methods, and therapeutic uses.
What is the Patent Landscape for EP2133325?
The patent landscape for riluzole formulations involves numerous patents covering the active ingredient itself, various synthetic routes, polymorphs, and different pharmaceutical compositions designed to improve drug delivery, stability, and patient compliance. EP2133325 occupies a specific niche within this landscape by focusing on an acidifying agent to enhance riluzole dissolution and bioavailability.
Key Players and Their Patents
Companies active in the riluzole market and research include, but are not limited to, Sanofi-Aventis (now Sanofi), Cytokinetics, and various generic manufacturers.
- Sanofi-Aventis/Sanofi: As the assignee of EP2133325, Sanofi holds significant intellectual property related to riluzole. Other Sanofi patents may cover different aspects of riluzole, such as its synthesis or other formulation types. For instance, patents related to riluzole manufacturing processes or its therapeutic applications would be relevant.
- Cytokinetics: This company has been involved in the development of riluzole and its analogues, and holds patents related to its compounds and their uses.
- Generic Manufacturers: Upon patent expiry, generic companies actively seek to enter the market with their own riluzole products. Their R&D often focuses on developing formulations that circumvent existing patents or offer improved characteristics while not infringing on active patents. This involves navigating the claims of patents like EP2133325.
Overlapping and Adjacent Technologies
The patent landscape is complex, with patents often overlapping or being adjacent to each other.
- Original Riluzole Patents: The foundational patents for riluzole itself, covering its composition of matter, have long expired. This allows for generic competition for the basic drug.
- Formulation Patents: Patents like EP2133325 focus on specific formulations. These patents are critical for market exclusivity beyond the initial composition of matter patents. Competitors must design formulations that do not fall within the scope of these claims.
- Polymorph Patents: Patents covering specific crystalline forms (polymorphs) of riluzole can also extend market exclusivity, as a different polymorph may not infringe on a polymorph patent.
- Method of Treatment Patents: Patents may cover novel methods of using riluzole for treating specific diseases or patient populations.
- Manufacturing Process Patents: Patents related to novel and efficient manufacturing processes for riluzole or its formulations can also be strategically important.
The presence of EP2133325 means that any manufacturer wishing to produce a riluzole formulation that includes riluzole, a diluent, a disintegrant, a lubricant, and an organic acidifying agent, particularly if produced by dry granulation or direct compression and presented as a tablet, must assess potential infringement.
How Can Competitors Navigate the Claims of EP2133325?
Navigating the claims of EP2133325 requires a detailed understanding of its scope and careful formulation design.
Circumvention Strategies
Competitors can explore several strategies to avoid infringing on EP2133325:
- Omission of a Key Element: The most straightforward approach is to omit one of the claimed essential elements. For example, a formulation that does not include an acidifying agent would not fall under Claim 1.
- Use of Alternative Excipients: While Claims 2-6 specify preferred or exemplified excipients (organic acids, specific diluents, disintegrants, lubricants), the broadest claim (Claim 1) simply requires "an acidifying agent," "a diluent," etc. However, if the formulation uses excipients outside the scope of the dependent claims, it might still infringe Claim 1 if those excipients are equivalent in function and fall within the general definitions. However, using a non-organic acidifying agent or entirely different classes of diluents, disintegrants, or lubricants could potentially avoid infringement.
- Different Dosage Form: The patent claims a "solid oral pharmaceutical formulation" and dependent claims specify a "tablet." Formulations that are not solid oral dosage forms (e.g., liquids, injectables) would not infringe. However, the core invention appears to be tied to improving oral delivery.
- Different Manufacturing Process: Claims 7 and 8 specifically mention dry granulation and direct compression. Formulations manufactured using entirely different processes (e.g., wet granulation followed by tableting, or encapsulation of granules not produced by these methods) might avoid infringement of these dependent claims, but the core composition of matter claim would still need to be assessed.
- Non-Infringing Equivalents: Competitors must also consider the doctrine of equivalents. If a component or process used is substantially the same in function, way, and result as a claimed element, it could still be considered infringing.
Freedom to Operate (FTO) Analysis
A thorough Freedom to Operate (FTO) analysis is crucial. This involves:
- Claim Chart Analysis: A detailed comparison of a competitor's proposed formulation against each claim of EP2133325, element by element.
- Prior Art Search: Identifying prior art that may invalidate EP2133325, potentially rendering it unenforceable. This includes searching for publications or earlier patents that disclose the claimed invention before its priority date.
- Patentability of Alternative Formulations: If a competitor develops an alternative formulation, ensuring it is patentable itself is also a consideration.
What is the Market Significance of EP2133325?
EP2133325 is significant because it protects a formulation that enhances the therapeutic profile of riluzole, a critical drug for ALS patients. The patent provides Sanofi with a period of market exclusivity for this improved formulation, impacting the competitive dynamics of the riluzole market.
- Market Exclusivity: The patent grants Sanofi a period during which other companies are generally prevented from making, using, or selling the patented formulation within the European territories covered by the patent. This exclusivity is vital for recouping R&D investment and maintaining market share.
- Impact on Generic Entry: The expiration date of EP2133325 (July 20, 2027) signals a potential market entry point for generic manufacturers of this specific formulation. Until then, generic versions must offer formulations that do not infringe on the patent.
- Value of Improved Formulations: The patent highlights the commercial value of developing improved pharmaceutical formulations. By addressing issues like bioavailability and dissolution, the patented formulation offers a tangible benefit over potentially less effective or less stable prior art. This incentivizes further R&D in formulation science.
- Therapeutic Importance of Riluzole: Riluzole is one of the few drugs approved for slowing the progression of ALS. Any patent protecting an improved formulation of such a critical therapy carries significant weight in terms of patient access and healthcare economics.
Conclusion
EP2133325 is a key patent protecting a specific solid oral pharmaceutical formulation of riluzole, distinguished by the inclusion of an acidifying agent to improve dissolution and bioavailability. Its claims define a composition and, in dependent claims, manufacturing methods and specific excipients. The patent landscape is complex, with multiple entities involved in riluzole development. Competitors must conduct rigorous FTO analyses and explore circumvention strategies, such as omitting key elements or developing entirely novel formulations, to navigate the patent's scope. The patent's significance lies in its role in market exclusivity for an improved riluzole formulation and its impact on the timeline for generic competition, particularly given the therapeutic importance of riluzole in ALS treatment.
Key Takeaways
- EP2133325 protects a solid oral riluzole formulation containing riluzole, a diluent, a disintegrant, a lubricant, and an acidifying agent.
- The primary benefit of the patented formulation is enhanced riluzole dissolution and bioavailability due to the acidifying agent.
- The patent is set to expire on July 20, 2027, creating a window for potential generic market entry for this specific formulation type.
- Competitors must carefully analyze the patent's claims to design non-infringing riluzole formulations.
- Circumvention strategies include omitting key claimed components, using alternative excipients, or employing different manufacturing processes.
Frequently Asked Questions
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What is the expiration date of EP2133325?
EP2133325 is set to expire on July 20, 2027.
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Can I manufacture a riluzole formulation that does not include an acidifying agent?
A formulation omitting an acidifying agent would likely not infringe Claim 1 of EP2133325, as the acidifying agent is a core element of the independent claim.
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Does EP2133325 cover all riluzole formulations?
No, EP2133325 specifically covers a solid oral pharmaceutical formulation with a defined set of components, including an acidifying agent. Many other riluzole formulations may exist that do not fall under its claims.
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What is the primary therapeutic use of riluzole as referenced in the patent?
While the patent's claims broadly mention "neurological disorders," Claim 11 specifically identifies amyotrophic lateral sclerosis (ALS) as a therapeutic application.
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What does "freedom to operate" mean in the context of EP2133325?
Freedom to operate (FTO) means conducting an analysis to determine if a proposed product or process (in this case, a riluzole formulation) can be made, used, or sold without infringing on existing intellectual property rights, such as EP2133325.
Citations
[1] Sanofi-Aventis Deutschland GmbH. (2012). European Patent EP2133325 B1: Pharmaceutical formulation of riluzole. European Patent Office.
