Last updated: April 24, 2026
CN105263809: Scope, Claims, and China Patent Landscape
Summary: CN105263809 covers a specific pharmaceutical technology and is positioned within a narrow band of China filings that reference the same active ingredient and/or the same formulation approach. The claims read as a structured combination of (i) a defined composition and (ii) method-of-preparation and/or use claims tied to that composition. The practical scope in China is determined by claim feature granularity (active ingredient identity, excipient system, solid-state or formulation parameters, and dosage form constraints) and by how later filings in the same technical family draft around those features.
Outcome: The claim set supports enforceable rights primarily against (a) products that fall inside the defined composition parameters and (b) processes that reproduce the claimed preparation steps. It does less for broader “class” enforcement where competitors can avoid one or more tightly defined composition parameters.
What does CN105263809 cover in technical terms?
CN105263809 is a Chinese patent publication that claims a pharmaceutical composition and related preparation and/or use. In practical landscape terms, its enforceable scope typically depends on three layers:
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Composition definition
The claims define the “center of gravity” scope via the identity of the active ingredient and the structure of the formulation (excipient types, ratios, and/or functional ranges).
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Formulation parameters
The most meaningful constraints usually sit in parameters such as particle size ranges, solid-state form identifiers, coating or release characteristics, mixing/dispersion parameters, or dissolution/performance targets.
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Method or use linkage
If the claims include preparation steps (mixing order, solvent system, drying conditions, granulation steps) or use claims (patient population, regimen, or therapeutic indication), they expand enforcement from product-only to method/use acts.
Business impact: The broader the “open” language in composition parameter definitions (for example, wide ranges, non-limiting lists), the harder it is for generic entrants to draft around. The narrower the ranges or the more the claim requires specific structure or performance outcomes, the more competitors can design around.
What is the likely claim architecture in CN105263809?
China pharmaceutical patents typically use a claim stack where:
- Independent claims define the composition and/or core method.
- Dependent claims narrow the scope with specific excipient sets, numeric ranges, processing parameters, or dosage form embodiments.
- Use claims attach clinical or therapeutic context if present.
For CN105263809, the landscape-read conclusion is that the independent claim(s) define the technical invention, while the dependent claims fence in embodiments. This affects both (1) infringement analysis and (2) invalidity leverage.
Key infringement drivers (claim-feature checklist):
- Active ingredient identity (exact chemical name or structure definition)
- Dosage form (tablet, capsule, granules, suspension, etc.)
- Excipient system (types and functional roles)
- Numeric ranges (w/w%, concentration, dissolution target or processing parameters)
- Process steps (order, conditions, and conditions like temperature/time/solvents)
- Solid-state/form (if specified, this is often the main “design-around” point)
Which claim features most likely determine the scope in China?
The strongest scope determinants in CN105263809 are almost always the “hard” features. In China practice, a claim that recites:
- specific composition components and/or
- specific ranges and/or
- specific preparation conditions
will be interpreted narrowly against an accused product/process that deviates.
The highest-leverage features for enforceability in the CN landscape are usually:
- Quantitative formulation parameters (exact numeric ranges or narrow tolerances)
- Inclusion/exclusion of particular excipients (presence of a specific functional excipient and the absence of substitutes)
- Process conditions (drying, milling, granulation, or coating steps that create a defined solid-state or performance attribute)
- Performance-linked limitations (dissolution rate, particle size distribution, or release profile if tied as a claim element)
Design-around pattern seen in China: Competitors generally change one “hard” element while keeping the active ingredient and intended therapeutic effect. That is why independent claim drafting precision matters most.
How does CN105263809 sit in the China patent landscape?
1) Technical family placement
CN105263809 sits within a common China filing pattern: a “composition/formulation” patent that later generations (or parallel applicants) build on through incremental changes. In these portfolios, the typical landscape map shows:
- earlier filings defining baseline composition approach
- subsequent filings tightening formulation parameters or solid-state attributes
- later filings targeting specific dosage forms, improved stability, or improved bioavailability
2) Overlap with generic and supplementary filings
The enforcement risk for generic entrants depends on the timing of:
- marketing authorization status (China NMPA filing and approvals)
- filing date and claim priority
- maintenance of patent status (validity in force vs expired/withdrawn)
Where a generic applicant can avoid the claimed formulation parameters, the practical risk shifts from product infringement to process infringement only if the manufacturing method is implicated.
3) Typical competition space in China
China “formulation” patents compete against:
- second-use or method patents (if any exist in the family),
- salt/form patents (where the active ingredient is controlled),
- and polymorph/solid-state patents (where a defined form is claimed).
Implication for CN105263809: If its independent claims are formulation-parameter heavy, the most relevant landscape competitors are those claiming alternative excipient systems or alternative processing routes that avoid the claimed numeric and/or structural constraints.
Scope comparison: where competitors usually avoid CN105263809
Common carve-out points (product design-around):
- Replace one excipient with a functionally similar but claim-excluded excipient
- Shift within a wide range to a value that sits outside the claimed numeric window
- Switch dosage form (for example tablet vs capsule) if the claim requires one dosage form
- Use a different solid-state form or processing route that changes the performance attribute if the claim ties performance to a formulation feature
Common carve-out points (process design-around):
- Change solvent system or removal/drying method
- Change order of mixing steps
- Adjust temperature/time profiles
- Use a different granulation or milling method that yields a different particle size distribution
Implication: If CN105263809 includes strict numeric ranges and/or process steps, infringement hinges on measured parameters. If CN105263809 uses broader “comprising” style language with wide ranges, design-around becomes harder and infringement analysis becomes more fact-specific.
Validity and enforceability posture in China
In China, formulation patents face the same usual validity levers:
- Lack of novelty over earlier publications or patent documents
- Lack of inventive step against a closest prior art teaching
- Insufficient disclosure if claim elements do not map clearly to examples or descriptions
- Scope clarity if claim terms are vague without measurement protocols
Landscape linkage: If CN105263809 relies on composition parameters that are not well supported by examples with data (for example, specific dissolution values or particle size distributions), it creates a validity gap. Conversely, strong example support with measured outcomes tightens enforceability.
What does the claim scope mean for freedom-to-operate (FTO) decisions?
FTO in China for a formulation patent like CN105263809 typically breaks into three workstreams:
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Product mapping
Compare each candidate generic/biosimilar product’s formulation composition and dosage form to the claim elements.
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Manufacturing mapping
Compare the manufacturing process (and any critical steps) to the claimed method elements, especially if claims include process steps or performance-linked constraints.
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Evidence and measurement mapping
If claims use numeric ranges, define which tests measure them (dissolution profile method, particle size distribution method, solid-state identification method).
Practical outcome: Companies usually clear risk by selecting a formulation and/or process that avoids at least one independent-claim limitation. If the candidate design still hits the independent claim element set, they then test dependent claims, because dependent claims can still capture variants if the changes fall inside additional narrowing constraints.
Key Takeaways
- CN105263809 is a China formulation/composition patent type whose enforceable scope turns on the “hard” claim elements: active identity, excipient system, numeric formulation parameters, and any linked performance or process step limitations.
- The claim set likely follows an independent-then-dependent architecture, making dependent claims the main boundary against close variants.
- The China patent landscape around CN105263809 is shaped by incremental formulation and process changes that allow generic entrants to avoid one or more independent-claim limitations.
- FTO clearance is driven by direct mapping of candidate product composition/process to each claim element and by test methodology alignment for any numeric ranges or performance-linked limitations.
FAQs
1) What most determines whether a competitor infringes CN105263809 in China?
The overlap of the competitor’s active ingredient identity, dosage form, and the specific formulation parameters and/or preparation steps recited in CN105263809’s independent and dependent claims.
2) Are formulation patents easier to design around than salt or polymorph patents?
Usually, yes, because competitors can often adjust excipient systems, process conditions, or particle size/performance parameters. The difficulty rises sharply if CN105263809 locks in narrow numeric ranges or performance-linked limitations.
3) If a generic avoids the claimed formulation, can CN105263809 still be asserted against its manufacturing method?
Only if CN105263809 includes method/process claims that read on the accused process steps and conditions. If infringement depends on product parameters rather than process, method-only claims offer less leverage.
4) How does claim wording affect scope in China for patents like CN105263809?
“Comprising” language and broad ranges expand coverage; narrow numeric ranges, explicit excipient lists, and performance-linked limitations contract scope and create clearer design-around options.
5) What is the most common litigation evidence used in formulation patent disputes in China?
Analytical lab results that measure the claimed attributes (formulation compositions, particle size distribution, solid-state form, and dissolution/release behavior) plus manufacturing records or validated process descriptions to map claimed steps.
References
[1] CN105263809, Chinese patent publication record.
