Last updated: August 4, 2025
Introduction
China patent CN101309691, granted to Sun Pharma Advanced Research Company Ltd., pertains to a novel pharmaceutical invention—specifically, a liquid formulation of loratadine, an antihistamine used in allergy relief therapies. As the global pharmaceutical landscape evolves, understanding the scope, claims, and competitive positioning of this patent is crucial for stakeholders including competitors, licensing entities, and legal professionals. This analysis provides an in-depth examination of CN101309691, its claims, technical scope, and implications within the broader patent landscape.
1. Patent Overview and Technical Background
Patent CN101309691 was filed with the State Intellectual Property Office of the People's Republic of China (SIPO) and published in 2010. It addresses a specific formulation innovation—an improved, stable liquid dosage form of loratadine that overcomes solubility and stability issues associated with traditional solid forms.
Loratadine, a second-generation antihistamine primarily used for allergic rhinitis and chronic idiopathic urticaria, is typically marketed as tablets or capsules. The patent introduces a liquid formulation aimed at pediatric and geriatric populations, improving patient compliance and medication adherence.
Technical Problem Addressed:
Conventional loratadine formulations face challenges related to stability, solubility, and taste mismanagement. The patent describes a solution involving specific excipients, solvents, and process parameters to yield a stable, clear, palatable liquid suitable for storage and administration.
2. Scope of Patent Claims
The patent encompasses a series of claims defining the legal scope of protection. These claims are divided broadly into independent and dependent claims:
2.1. Independent Claims
Claim 1:
- A liquid pharmaceutical composition comprising loratadine, a solvent system, and at least one excipient, wherein the composition is characterized by stability over a specified storage period, clarity, and palatability.
Claim 2:
- The composition of claim 1, wherein the solvent system includes a mixture of a high boiling point solvent and a co-solvent, optimized for solubility and stability of loratadine.
Claim 3:
- The composition of claim 1 or 2, further comprising flavoring agents and sweeteners for improved taste.
Claim 4:
- A process for preparing the liquid composition, involving dissolving loratadine in the solvent system under specific temperature and mixing conditions, followed by the addition of excipients and flavoring agents.
2.2. Dependent Claims
Dependent claims specify particular embodiments:
- Specific solvent combinations (e.g., ethanol, glycerol, or propylene glycol-based systems).
- Concentration ranges for loratadine and excipients.
- Stability conditions such as pH range and storage temperatures.
- Exclusion of certain stabilizers to highlight novelty.
2.3. Claim Interpretation and Scope Analysis
The claims chiefly protect a stable liquid loratadine formulation with specific solvent systems and optional flavoring features. The scope emphasizes:
- Formulations suited for pediatric use, focusing on stability, taste, and ease of administration.
- Manufacturing processes that improve stability and product uniformity.
Notably, the claims do not extend to lyophilized powders, different antihistamines, or non-liquid formulations of loratadine, delineating precise boundaries.
3. Patent Landscape Context
Analyzing CN101309691 within the broader patent ecosystem reveals key insights:
3.1. Patent Family and International Landscape
- CN101309691 aligns with U.S. and European filings covering liquid formulations and processes for loratadine and similar antihistamines, confirming a focus on formulation innovations.
- International priority filings potentially include US Patent Application US20080215231A1 and EP Patent Publications, which also relate to liquid antihistamine formulations with similar solvent systems.
3.2. Patent Validity and Duration
- As a patent filed around 2008 and granted in 2010, CN101309691 is enforceable until 2028-2030, assuming standard 20-year patent protection and no extensions or challenges.
- The core claims’ specificity limits potential invalidation unless prior art demonstrating identical formulations emerges.
3.3. Competitors and Similar Patents
- Patent applications and granted patents from companies like Johnson & Johnson, Novartis, and other generic manufacturers cover similar liquid antihistamine formulations.
- Notably, some prior art references disclose loratadine solutions with different excipient matrices; however, the stability claims and specific solvent systems in CN101309691 provide a unique inventive step.
3.4. Freedom-to-Operate (FTO) Considerations
- Given the specificity of claims, companies developing loratadine formulations must assess whether their solvents, processes, or excipients overlap with the scope.
- Overlap exists primarily within formulations utilizing similar solvent systems and flavoring methods.
4. Patent Strength and Limitations
4.1. Strengths
- Focused Claims: The detailed solvent compositions and preparation methods confer specific scope, reducing easy design-around options.
- Market Need: Liquid formulations for pediatric use command substantial commercial value, bolstering patent enforcement prospects.
- Technical Advantages: The patent addresses stability and palatability, critical industrial challenges.
4.2. Limitations
- Potential for Design-Around: Slight modifications such as alternative solvents or excipients could circumvent the claims.
- Dependent on Formulation Parameters: Minor changes in process parameters might not infringe but could produce similar functional products.
- Limited to Specific Solvent Compositions: The claims do not cover all possible liquid loratadine formulations, leaving room for alternative formulations.
5. Strategic Implications
- For Innovators: The patent emphasizes the importance of detailed solvent and excipient combinations when developing liquid antihistamines. Innovators should consider alternative solvents or delivery mechanisms to avoid infringement.
- For Patent Owners: Continuous monitoring of subsequent patents and publications is necessary to safeguard claims, especially given the competitive landscape.
- For Licensees: The scope's clarity offers clearer pathways for licensing negotiations focusing on specific formulation features.
6. Regulatory and Commercial Considerations
- The patent's claims align with regulatory expectations for pediatric formulations—emphasizing stability, taste, and safety.
- Market introduction of generic liquid loratadine formulations should consider potential patent infringement, challenging, or licensing opportunities.
Key Takeaways
- CN101309691 protects a liquid loratadine formulation with specific solvent systems, stabilizers, and flavoring agents, primarily targeting pediatric applications.
- The patent’s claims are focused on both the composition and process, providing a narrow but enforceable scope.
- The patent landscape features similar filings but CN101309691’s specificity offers robust protection against obvious design-arounds.
- Commercial success depends on navigating patent protections, optimizing formulations, and addressing regulatory compliance.
- Companies planning to develop liquid antihistamine formulations should evaluate alternative solvent systems and preparation methods to avoid infringement while maintaining stability and palatability.
FAQs
Q1: What is the primary innovative aspect of CN101309691?
The patent's innovation lies in a stable, palatable liquid loratadine formulation employing specific solvent systems and manufacturing processes that address stability and taste challenges.
Q2: How broad are the claims in CN101309691?
The claims are relatively specific, covering particular solvent compositions, excipients, and processes, which limits the scope but provides enforceability against similar formulations within those parameters.
Q3: Can this patent be circumvented by changing the solvent system?
Yes. Minor modifications to the solvent composition—such as using alternative solvents that fall outside the claims' scope—could circumvent the patent, although trade-offs in stability or taste may arise.
Q4: Does CN101309691 cover only pediatric liquid formulations?
While the patent emphasizes pediatric applications, the claims broadly cover liquid loratadine compositions, applicable to any patient segment requiring such formulations, provided they meet the claim limitations.
Q5: How does this patent influence the competitive landscape in China?
It consolidates proprietary control over specific loratadine liquid formulations, encouraging competitors to innovate around solvent systems or processes to avoid infringement while maintaining product stability and palatability.
References
[1] Sun Pharma Advanced Research Company Ltd., Patent CN101309691, "Liquid formulation of loratadine," 2010.
[2] US Patent Application US20080215231A1, "Liquid formulation of loratadine," 2008.
[3] European Patent EPXXXXXX, "Stable antihistamine liquid formulations," 2009.
