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Patent landscape, scope, and claims: |
United States Patent 8,450,375 Scope, Claims, and Topical Formulation Patent Landscape
US Patent 8,450,375 is directed to a specific topical formulation: bis(2-chloroethyl)methylamine (BCEMA) (or salts) at low wt% together with (i) a defined glycol ether excipient and (ii) one of a narrow set of stabilizer/chelating alcohol phenol derivatives. The claims are composition-focused (not method-of-use) and tie down excipient identity and quantitative ranges, creating potential design-around space via different excipient classes, excipient substituent structure, or BCEMA loading outside the claimed ranges.
Key claim determinants
- Active: bis(2-chloroethyl)methylamine (free base or salts).
- Quantitative range: about 0.001% to about 2.0% by weight of the composition (dependent claims narrow to 0.01% to 0.04%).
- Excipient #1 (must match formula): HOCH2CH2OCH2CH2OR79, where R79 is linear alkyl C1 to C6.
- Excipient #2 (one of three): butylated hydroxytoluene (BHT), edetate disodium (EDTA disodium), or benzyl alcohol.
- Salts: dependent claims specify HCl, HBr, HI, H2SO4, HNO3 salts and single out HCl.
- Subrange: dependent claim specifies R79 = 2-carbon linear alkyl (explicitly labeled as “ethoxy diglycol reagent”).
What is claimed in US Patent 8,450,375 (composition scope and literal boundaries)?
Independent claim 1 defines a topical composition with three elements that must be satisfied together:
- BCEMA or a pharmaceutically acceptable salt
- First excipient: glycol ether of formula HOCH2CH2OCH2CH2OR79
- Second excipient: BHT or EDTA disodium or benzyl alcohol
Plus a BCEMA wt% window.
Claim 1: full element breakdown
Claim 1 requires:
- Active/amount
- BCEMA (or salt) is present in about 0.001% to about 2.0% by weight.
- Excipient 1 identity
- First excipient is a compound of formula:
HOCH2CH2OCH2CH2OR79
- R79 is linear alkyl C1 to C6.
- This is the most structure-limiting feature besides BCEMA and excipient #2.
- Excipient 2 identity
- Second excipient is BHT OR EDTA disodium OR benzyl alcohol.
Interpretation implications for scope
- Because excipient #1 is defined by a structural formula and allowable substituent range, the claim has clearer chemistry boundaries than a generic “surfactant” or “stabilizer” claim.
- Because excipient #2 is constrained to a list of three specific excipients, replacing excipient #2 with another stabilizer may fall outside literal claim 1.
Dependent claims: what they narrow
- Claim 2: BCEMA is in acid-addition or base-addition salt form.
- Claim 3: acid-addition salts specifically HCl, HBr, HI, H2SO4, or HNO3.
- Claim 4: acid-addition salt is HCl.
- Claim 5: BCEMA wt% narrowed to about 0.01% to about 0.04%.
- Claims 6-8: specify which option is used for excipient #2:
- Claim 6: excipient #2 is BHT
- Claim 7: excipient #2 is EDTA disodium
- Claim 8: further comprises BHT when claim 7’s EDTA disodium is present (so this dependent claim requires EDTA plus BHT together).
- Claim 9: excipient #1 has R79 = 2 carbon linear alkyl (ethoxy diglycol reagent), tightening excipient identity.
How broad is the “glycol ether excipient” limitation in claim 1 (R79 C1–C6)?
Claim 1’s excipient #1 is not just “any polyether,” but a specific HO–(CH2CH2O)–(CH2CH2O)–R structure where R is a linear alkyl C1–C6.
Practical scope analysis for R79
- The claim covers R79 = C1, C2, C3, C4, C5, or C6 linear alkyl groups.
- Claim 9 is a further subset: R79 = 2 carbons (C2 alkyl).
Design-around pressure points
- Changing the end group R outside C1–C6 linear alkyl may avoid excipient #1.
- Changing the scaffold so it is not exactly HOCH2CH2OCH2CH2OR79 should avoid literal infringement.
- If a product uses the same overall class (glycol ethers) but with different linkage pattern, branching, or a non-linear substituent, it can create strong non-infringement positions at the claim construction stage.
What does the excipient #2 list do to infringement risk (BHT vs EDTA vs benzyl alcohol)?
Claim 1 explicitly allows only:
- BHT
- edetate disodium (EDTA disodium)
- benzyl alcohol
Litigation-relevant consequence
A formulation that uses:
- a different antioxidant (other phenols, tocopherols, butyl paraben, etc.)
- a different chelator (e.g., citrate, DTPA, EGTA)
- a different preservative/alcohol (propyl benzyl alcohol, isopropanol, etc.)
may avoid claim 1 on excipient #2 identity alone.
Dependent claim 8 increases overlap for EDTA + BHT combinations
- If a competitor uses EDTA disodium plus BHT, it is pushed into claim 8 territory (assuming all other claim 1 elements are met).
How do the BCEMA concentration ranges affect claim coverage (0.001–2.0% and 0.01–0.04%)?
Claim 1 concentration window
- BCEMA wt%: about 0.001% to about 2.0%
Claim 5 concentration subrange
- BCEMA wt%: about 0.01% to about 0.04%
Practical risk read-through
- A competitor using a BCEMA loading below the lower bound or above the upper bound can create straightforward literal non-infringement.
- Because concentrations are “about” ranges, exact boundary engineering matters less than whether a product plausibly lands outside the window as argued under standard “about” interpretation.
What salt forms are covered (HCl singled out)?
- Claim 2 covers BCEMA in acid-addition or base-addition salt form.
- Claim 3 specifies acid-addition salts:
- HCl, HBr, HI, H2SO4, HNO3
- Claim 4 tightens to HCl salt.
Infringement and settlement leverage
- If a marketed product uses BCEMA in HCl salt form, it is closer to the strongest dependent claim set.
- If another product uses BCEMA as a different counterion not listed in claim 3 but still an acid-addition salt, claim 3 may not read, but claim 2 could still capture it.
What patent landscape questions matter for a topical BCEMA formulation (and where US 8,450,375 likely sits)?
Even without additional bibliographic data here, the claim structure indicates US 8,450,375 is a formulation composition patent that can be attacked or avoided by:
- removing one required excipient,
- swapping excipient identities,
- moving BCEMA loading outside ranges,
- changing excipient #1 scaffold or R79 range,
- changing salt form outside specified lists.
How this patent typically fits among estates
Formulation portfolios in this space often include:
- earlier patents on BCEMA itself or broad pharmaceutical compositions
- patents on specific salts
- patents on topical dosage forms and vehicle systems
- patents on stability/stabilizers and excipient combinations
- later “improvement” patents that define excipient identities and specific concentration windows (as here)
US 8,450,375 reads like the last category: it narrows to a very specific combination.
What is the US exclusivity and “Orange Book” status for US 8,450,375?
No Orange Book linkage can be established from the claim text alone. Without the specific FDA application/listed drug name and the Orange Book patent reference, the patent’s regulatory exclusivity tie cannot be determined from the information provided.
Are there biosimilar or biologic pathways at risk here?
The patent is for a small-molecule topical composition (BCEMA). Biosimilar frameworks are not applicable on the basis of the claim set.
Which generic entry risks exist for compositions covered by US 8,450,375?
A generic faces high literal-infringement barriers if it matches all three elements
To risk infringement of claim 1, an ANDA-style generic (or an OTC/alternate NDA topical product) must match:
- BCEMA present in 0.001–2.0%
- glycol ether HOCH2CH2OCH2CH2OR79 with R79 C1–C6
- one of BHT/EDTA disodium/benzyl alcohol
Most feasible generic escape routes
- Replace excipient #1 with a glycol ether outside the HOCH2CH2OCH2CH2OR79 scaffold or with R79 outside C1–C6
- Replace excipient #2 with a different antioxidant/chelator/preservative not listed
- Use BCEMA loading outside 0.001–2.0% (or outside 0.01–0.04% for formulations tuned to dependent claim 5)
Settlement leverage
Because claim 1 is combination-bounded, settlement agreements often reduce to:
- “carve-outs” where the ANDA uses a different excipient system, and
- noninfringement positions focused on one element (excipient identity or scaffold)
How strong is the patent estate likely to be around US 8,450,375 (claim chemistry and enforcement posture)?
Strength signals
- Excipient #1 is defined by a specific chemical formula with bounded substituent range (R79).
- Excipient #2 is limited to a three-excipient list.
- BCEMA loading windows are numeric.
These features often make infringement analysis more objective: a formulation either matches the defined chemical structures and the permitted excipient list or it does not.
Weakness signals (typical for this claim type)
- If prior art disclosed:
- BCEMA topical formulations with glycol ether excipients and standard antioxidants/chelators,
the claim could face obviousness or lack-of-inventive-step challenges.
- If prior art disclosed the same excipient combinations with different BCEMA loading, concentration-range optimization can still be challenged.
What do the claims suggest about potential manufacturing/IP barriers for competitors?
A competitor can clear IP risk by changing at least one of:
- excipient #1 scaffold or R79 substituent class
- excipient #2 identity
- BCEMA salt/counterion (for claim 3 and claim 4 emphasis)
- BCEMA concentration
Since the patent is not method-of-use limited, manufacturing substitutions are the primary IP barrier, not dosing regimens.
Key Takeaways
- US 8,450,375 claim 1 covers a narrow topical BCEMA formulation defined by: BCEMA wt% 0.001–2.0%, glycol ether HOCH2CH2OCH2CH2OR79 with R79 = linear C1–C6, and excipient #2 as BHT, EDTA disodium, or benzyl alcohol.
- Dependent claims tighten concentration (0.01–0.04%), salt identity (HCl singled out), and excipient #1 specifically to R79 = C2.
- Design-around is most achievable by replacing excipient #2 (not in the permitted list), altering excipient #1’s structure/substituent, or moving BCEMA concentration outside the claimed ranges.
- Orange Book / regulatory linkage cannot be determined from claim language alone.
- Biosimilar pathways are not implicated; this is a small-molecule formulation patent.
FAQs
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Can a product avoid claim 1 by using EDTA disodium but not BHT?
Yes, because claim 1 permits EDTA disodium alone as excipient #2; avoiding BHT only affects dependent claim 8, not claim 1, if all other elements match.
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Does claim 1 require the specific “ethoxy diglycol reagent” (R79 = 2 carbon)?
No. Claim 9 requires R79 = C2, but claim 1 covers R79 as linear alkyl C1–C6.
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If BCEMA is present at 0.05% by weight, does claim 5 apply?
No. Claim 5 limits BCEMA to about 0.01% to 0.04%. Claim 1 could still apply if 0.05% is within about 0.001–2.0%.
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Is HCl salt required for infringement?
No. HCl is only required for the specific dependent salt claim (claim 4). Claim 1 requires only BCEMA or a pharmaceutically acceptable salt.
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If a formulation uses a different chelator like citrate, can it still infringe?
Not on a claim 1 excipient #2 theory, if citrate is not one of the enumerated excipients (BHT, EDTA disodium, benzyl alcohol).
References (APA)
- United States Patent 8,450,375.
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