United States Patent 6,217,909: Scope of Claims and Positioning in the US Excipient Landscape
United States Patent 6,217,909 claims an excipient composition built around a particulate agglomerate of coprocessed microcrystalline cellulose (MCC) and silicon dioxide (SiO2), with tight numerical limits on SiO2 content, SiO2 particle-size or source type, agglomerate particle size, and bulk density.
The claim set is structured as a core independent claim (claim 1) plus multiple dependent claims that narrow:
- the SiO2 primary particle size range,
- whether SiO2 is colloidal,
- SiO2 loading windows (including narrow “sweet spots”),
- excipient particle size distributions,
- moisture,
- optional additional excipient components, and
- SiO2 surface area constraints, and
- a bulk density band.
A second independent claim (claim 15) largely restates the concept while adding combined constraints (bulk density and average particle size together).
What is the invention’s defined structure in claim language?
Core excipient architecture (claim 1)
Claim 1 requires all of the following, in combination:
- An excipient composition
- Comprising a particulate agglomerate of:
- coprocessed microcrystalline cellulose
- and from about 0.1% to about 20% by weight silicon dioxide
- Intimate association between MCC and SiO2 inside the agglomerate
- The SiO2 is derived from a SiO2 having average primary particle size: 1 nm to 100 μm
- The final excipient bulk density is 0.35 g/mL to 0.6 g/mL
Claim 1 is the broadest in the set: it is permissive on (i) SiO2 primary particle size within 1 nm to 100 μm and (ii) excipient particle size (not constrained in claim 1), and it only partially narrows bulk density.
Independent claim 15: reinforced numerical enclosure
Claim 15 repeats the architecture with additional coupled constraints:
- Particulate agglomerate of coprocessed MCC and 0.1% to 20% SiO2
- Intimate association
- SiO2 derived from SiO2 with average primary particle size 1 nm to 100 μm
- Bulk density 0.2 g/mL to 0.6 g/mL
- Average excipient particle size 10 μm to 1,000 μm
This claim tightens product characterization by requiring both:
- a combined density range, and
- an average particle size range.
How broad is the claim scope numerically?
Silicon dioxide loading (claims 1, 4–6, 20)
The invention spans wide and then narrows:
| Parameter |
Claim language |
Scope impact |
| SiO2 wt% (broad) |
0.1% to 20% (claims 1, 15, 20) |
Establishes the commercial operating envelope |
| Preferred narrowing |
0.5% to 10% (claim 5) |
Cuts out very low (0.1–0.5) and very high (10–20) |
| Narrower band |
1.25% to 5% (claim 6) |
Targets mid-loading formulations commonly used for flow/processing |
SiO2 primary particle size (claims 1, 2, 18)
| Parameter |
Claim |
Range |
| Broad primary particle size |
claim 1 |
1 nm to 100 μm |
| Intermediate range |
claim 2 |
5 nm to 40 μm |
| Narrow dependent |
claim 18 |
5 nm to 40 μm (same as claim 2) |
Excipient particle size (claims 7–9, 15–17)
Claim 1 does not impose an average particle-size requirement. The dependent claims do:
| Claim |
Average particle size range |
| claim 7 |
10 μm to 1,000 μm |
| claim 8 |
10 μm to 500 μm |
| claim 9 |
30 μm to 250 μm |
| claim 15 (independent) |
10 μm to 1,000 μm |
| claim 16 |
10 μm to 500 μm |
| claim 17 |
30 μm to 250 μm |
Bulk density (claims 1, 14, 15)
| Claim |
Bulk density range |
| claim 1 |
0.35 g/mL to 0.6 g/mL |
| claim 14 |
0.35 g/mL to 0.55 g/mL |
| claim 15 |
0.2 g/mL to 0.6 g/mL |
Net effect: claim 15 is broader on low-density products (0.2–0.35 g/mL) while claim 1 is restricted to 0.35–0.6 g/mL.
Moisture content (claim 10)
- Moisture: 0.5% to 15% (claim 10)
This imposes a meaningful processing and storage envelope, since moisture affects flow, agglomeration, and rehydration/conditioning.
Surface area of SiO2 (claims 12–13)
- Surface area (claim 12): 10 m²/g to 500 m²/g
- Narrow band (claim 13): 175 m²/g to 350 m²/g
This is a major tightening dimension because manufacturers often select SiO2 by BET surface area grade.
SiO2 source type: “colloidal” (claims 3, 19)
- “Derived from colloidal silicon dioxide” (claims 3 and 19)
This is not a numeric restriction, but it can be outcome-determinative because colloidal SiO2 suppliers and product grades have defined characteristics.
What optional scope expansion exists beyond MCC + SiO2?
Claim 11 adds that the excipient particles can further comprise members of:
- non-silicon metal oxides
- starches
- starch derivatives
- surfactants
- polyalkylene oxides
- celluloses
- cellulose ethers
- cellulose esters
- and mixtures of these
This is “stackable” with claim 1 (as a dependent claim), meaning a formulation with extra excipients can still fall within the protected composition set if it otherwise meets the coprocessed agglomerate and SiO2 intimate-association requirements.
What is the practical infringement trigger? (Claim-to-product mapping)
The claim set hinges on five elements that are typically measurable and controllable:
-
Composition identity
- “excipient composition” comprising MCC + SiO2
-
Material architecture
- “particulate agglomerate of coprocessed MCC and SiO2”
- “microcrystalline cellulose and silicon dioxide being in intimate association”
-
Loading
- SiO2 wt% between 0.1% and 20% (or tighter windows in dependent claims)
-
SiO2 provenance characteristics
- derived from SiO2 having primary particle size in 1 nm to 100 μm, and optionally 5 nm to 40 μm, and/or derived from colloidal SiO2
- derived from SiO2 having BET surface area within specified windows (10–500 m²/g; narrow 175–350 m²/g)
-
Finished excipient bulk and particle size
- bulk density in 0.35–0.6 g/mL (claim 1) and/or 0.2–0.6 g/mL (claim 15)
- average particle size in 10–1,000 μm (claim 7 or claim 15) and narrower bands in claims 8–9 and 16–17
For portfolio strategy, the tightest “product fingerprint” in claim 1 is the bulk density band plus the intimate coprocessed agglomerate with defined SiO2 provenance. For claim 15, the “double fingerprint” is bulk density plus average particle size.
How does the claim set read as a landscape position?
Focused subject matter
The claims are not about:
- drug compounds
- dosage forms
- binding agents like povidone
- specific tablet/coating processes
They are about excipient particle engineering, specifically coprocessing MCC with SiO2 to produce an excipient grade defined by bulk behavior and particle characteristics.
Commercially actionable knobs
The dependent claims map to the manufacturing knobs that scale:
- select SiO2 grade by primary particle size
- select by BET surface area
- set loading (0.1–20 wt%)
- control processing moisture (0.5–15%)
- target flow-related metrics indirectly via bulk density and particle size
- permit formulation latitude via claim 11
US patent landscape implications for similar excipients (business take)
Without enumerating unrelated US patents by number (not provided here), the claim structure indicates how other players will design around or design into protection:
Design-around vectors
-
Break the “intimate association” / coprocessed agglomerate requirement
- If SiO2 is blended rather than forming intimate agglomerate with coprocessed MCC, the architecture element becomes a moving target.
-
Exit the SiO2 wt% envelope
- Avoid 0.1–20% (and especially the 0.5–10% and 1.25–5% bands) if practical.
-
Exit bulk density and/or particle size bands
- Claim 1: bulk density must be 0.35–0.6 g/mL
- Claim 15: bulk density must be 0.2–0.6 g/mL and average particle size 10–1,000 μm
-
Use SiO2 grades outside key provenance bands
- Primary particle size outside 1 nm–100 μm or specifically outside 5 nm–40 μm
- BET surface area outside 10–500 m²/g and especially outside 175–350 m²/g
-
Avoid “colloidal silicon dioxide” sourcing where the product is engineered from non-colloidal grades
Design-in vectors
- Use SiO2 grades that satisfy primary particle size and BET surface area bands
- Target bulk density 0.35–0.55 g/mL for the dependent claim 14 position
- For robust coverage, align with the more specific dependent particle-size windows (30–250 μm is narrower and may correlate with certain standard excipient sieves)
Detailed claim-by-claim scope (from your provided set)
Claim 1 (independent)
- Excipient composition
- Particulate agglomerate of coprocessed MCC + 0.1–20 wt% SiO2
- MCC and SiO2 in intimate association
- SiO2 derived from primary particle size 1 nm–100 μm
- Bulk density 0.35–0.6 g/mL
Claim 2 (dependent)
- Claim 1 plus SiO2 derived from primary particle size 5 nm–40 μm
Claim 3 (dependent)
- Claim 1 plus SiO2 derived from colloidal silicon dioxide
Claim 4 (dependent)
- Claim 1 plus SiO2 amount 0.1–20 wt% based on MCC weight (matches claim 1’s concept but explicitly ties base)
Claim 5 (dependent)
- Claim 1 plus SiO2 amount 0.5–10 wt% based on MCC weight
Claim 6 (dependent)
- Claim 1 plus SiO2 amount 1.25–5 wt% based on MCC weight
Claim 7 (dependent)
- Claim 1 plus excipient particles average size 10–1,000 μm
Claim 8 (dependent)
- Claim 1 plus average size 10–500 μm
Claim 9 (dependent)
- Claim 1 plus average size 30–250 μm
Claim 10 (dependent)
- Claim 1 plus moisture 0.5–15%
Claim 11 (dependent)
- Claim 1 plus further comprising one or more: non-silicon metal oxides, starches/starch derivatives, surfactants, polyalkylene oxides, celluloses and cellulose derivatives/esters
Claim 12 (dependent)
- Claim 1 plus SiO2 derived from surface area 10–500 m²/g
Claim 13 (dependent)
- Claim 1 plus SiO2 derived from surface area 175–350 m²/g
Claim 14 (dependent)
- Claim 1 plus bulk density 0.35–0.55 g/mL
Claim 15 (independent)
- Same core agglomerate and SiO2 provenance (1 nm–100 μm) and loading 0.1–20 wt%
- Bulk density 0.2–0.6 g/mL
- Average particle size 10–1,000 μm
Claim 16 (dependent)
- Claim 15 plus average particle size 10–500 μm
Claim 17 (dependent)
- Claim 15 plus average particle size 30–250 μm
Claim 18 (dependent)
- Claim 15 plus SiO2 derived from primary particle size 5 nm–40 μm
Claim 19 (dependent)
- Claim 15 plus SiO2 derived from colloidal silicon dioxide
Claim 20 (dependent)
- Claim 15 plus SiO2 amount 0.1–20 wt% based on MCC weight
Key Takeaways
- The patent protects a specific excipient engineering outcome: coprocessed MCC-SiO2 particulate agglomerates with intimate association.
- Independent claims 1 and 15 cover the same core architecture but differ on bulk density (0.35–0.6 vs 0.2–0.6) and on whether average particle size is required (claim 15 yes; claim 1 no).
- The strongest numeric narrowing is concentrated in: SiO2 wt% (0.5–10 and 1.25–5), SiO2 primary particle size (5 nm–40 μm), SiO2 BET surface area (10–500; 175–350 m²/g), and particle size windows (10–500; 30–250 μm).
- A second axis of scope is moisture (0.5–15%) and optional co-excipient inclusion (starches/cellulose derivatives/surfactants/oxides and related classes).
FAQs
-
Does the patent require a specific manufacturing method to form the agglomerate?
The claims require the outcome: “coprocessed” particulate agglomerate with intimate association between MCC and SiO2.
-
Which claim is broader on bulk density?
Claim 15 is broader because it covers 0.2–0.6 g/mL, while claim 1 covers 0.35–0.6 g/mL.
-
Are particle size limits required in claim 1?
No. Claim 1 does not require average particle size, but dependent claims 7–9 do. Claim 15 requires average particle size 10–1,000 μm.
-
Which SiO2 characteristics are most important for narrowing?
The claims can narrow by SiO2 primary particle size, by BET surface area, and by whether the SiO2 is colloidal.
-
Can additional excipients be present?
Yes. Claim 11 permits additional excipient classes (metal oxides, starches, surfactants, polyalkylene oxides, and cellulose-related materials), provided the core coprocessed MCC-SiO2 agglomerate requirements are met.
References
[1] U.S. Patent No. 6,217,909.
