United States Patent 3,885,046 (3,885,046) Landscape: What the Claims Cover, How Broad They Are, and Where Generics or Licensing Pivot
US Patent 3,885,046 is directed to antidepressant compositions and treatment methods using m-chloro-α-t-butylaminopropiophenone and m-fluoro-α-t-butylaminopropiophenone (and pharmaceutically acceptable acid addition salts), across oral, rectal, and parenteral dosage forms, with weight and dose ranges tied to “antidepressant-effective” amounts and specific unit strengths.
The patent’s enforceable scope tracks three claim “layers”:
- Compound-defined composition (formula + antidepressant-effective amount; weight range in dependent claims).
- Dosage-form and unit-dose constraints (tablets/capsules/sterile solutions or suspensions; unit mg ranges).
- Medical use (methods of treating depression in mammals; mammal human-specific language in later dependent claims; oral/parenteral mg/kg dose ranges).
This claim architecture tends to produce strong coverage against product substitution that keeps the same API or equivalent salts, and weaker coverage against therapeutic substitutes that do not use the claimed compounds (even if they treat depression).
Note on scope: From the claim text provided, the patent does not claim new polymorphs, new manufacturing steps, or specific controlled-release matrices. Its novelty footprint is centered on use of these specific substituted propiophenone amines (and salts) for depression, with dose and dosage-form ranges.
What patents protect m-chloro-α-t-butylaminopropiophenone and m-fluoro-α-t-butylaminopropiophenone for depression?
Which chemical matter is actually claimed
Claim 1 uses a “compound of the general formula” and includes “antidepressant-effective amount.” Claims 5-8 and 12-14 narrow to named species:
- m-chloro-α-t-butylaminopropiophenone
- m-fluoro-α-t-butylaminopropiophenone
- pharmaceutically acceptable acid addition salts of these compounds
The dependent composition and dosage claims explicitly call out specific salts at least for one form:
- Claim 8 and Claim 12: m-chloro-α-t-butylaminopropiophenone hydrochloride
That is a meaningful “handle” for enforcement against formulations using the hydrochloride salt.
What the “general formula” layer does
The formula-based claim (claim 1, and methods claim 9) is the broadest gate. It is designed to cover:
- the two named substituent variants and
- any within-scope members of the formula definition (as written in the patent specification)
Because the text you provided does not include the full formula definition, the actual breadth inside the formula cannot be fully mapped here. What can be stated from the claim chain you provided is that the two named species are unambiguously within scope, and the dependent claims further constrain to them.
What is not claimed
The claim set you provided does not include:
- specific salt identities beyond at least hydrochloride in claim 8/12
- stereochemical definitions (e.g., enantiomers)
- specific formulation technologies (enteric coating, sustained release, depot formulations)
- specific manufacturing processes or intermediates
- biomarkers, diagnostic criteria, or patient stratification
As a result, competing products that remain within the same API class but differ in formulation technology may still fall within claims 5-8 if they match dosage form and unit-dose structure.
What formulations are protected by US Patent 3,885,046 (tablets, capsules, sterile solutions, suppositories)?
Dosage forms explicitly claimed
The patent claims compositions in multiple physical forms:
- Oral/rectal composition (composition claim 1 with method support)
- Tablet (claim 5 and dependent claim 8)
- Capsule (claim 6)
- Parenteral sterile solution or suspension (claim 7)
- The claim text you provided does not explicitly name suppositories as such, but “oral or rectal administration” in claims 1/3 and method claims suggests rectal dosing is contemplated.
Unit-dose structure and strength limits
These claims impose hard quantitative boundaries that strongly affect infringement analysis.
Composition unit-dose ranges
-
Oral or rectal discrete unit (claim 3):
15 to 500 mg per dosage unit of the compound or acid addition salt, calculated as weight of base.
-
Parenteral discrete unit (claim 4):
7.5 to 250 mg per dosage unit, calculated as weight of base.
Specific tablet strength tied to hydrochloride
- Tablet (claim 8):
a tablet comprising 15 to 500 mg of m-chloro-α-t-butylaminopropiophenone hydrochloride plus carrier.
This is the most enforceable formulation claim in practice because it pins both:
- the dosage form (tablet) and
- the exact salt identity (hydrochloride) and
- the unit-strength band.
Method dose ranges reinforce the product strength logic
These method claims can be asserted even when a marketer argues a different salt form, provided the administration practice falls within the claimed dosing regimen and uses the claimed compound(s).
How strong is the patent estate for depression indications based on these claims?
Claim strength signals from the coverage model
From the claim set provided, enforceability strength typically comes from:
- specific API identity (named compounds in claims 5-8 and 12)
- explicit salt inclusion (acid addition salts generally; hydrochloride specifically in some claims)
- structural product capture (tablet/capsule/sterile solution or suspension)
- numerical unit-dose limits (15–500 mg oral/rectal; 7.5–250 mg parenteral)
- numerical dosing regimen (10–100 mg/kg oral/rectal; 5–50 mg/kg parenteral)
- indication framing (depressed state; “antidepressant-effective”)
Main litigation risk vectors
-
Design-around via outside-the-range dosing
A generic can attempt to avoid method-dose ranges by prescribing/administering regimens outside 10–100 mg/kg (oral/rectal) or 5–50 mg/kg (parenteral).
Product-level composition claims remain a challenge if the unit-strength and dosage form still fit claims 3/4/5-8.
-
Design-around via salt selection
Claim 5-7 cover “pharmaceutically acceptable acid addition salt.” Claim 8/12 specifically call hydrochloride. If a competitor uses a different salt, claim 8/12 may not read, but:
- claims 1/5/6/7 may still read because they include acid addition salts generally.
-
Design-around via non-overlapping dosage form
If a competitor uses an unclaimed dosage form (e.g., transdermal, inhalation, implant), claims 5-8 may not apply. Composition claim 1 is less dosage-form specific, but it requires compatibility with “composition suitable for use in treatment of depressed state.” In practice, the dosage form still matters in infringement arguments tied to “discrete dosage unit” and specific unit mg boundaries.
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Formulation-only changes
The claims you provided do not require particular excipients or release profiles. “Pharmaceutically acceptable carrier” is broad. Controlled-release vs immediate release arguments are weaker unless the product’s unit-dose definition and dosage-form class fall outside the claim language.
When does US 3,885,046 lose exclusivity for generic antidepressant competition?
No exclusivity timeline can be produced from the claim text you provided. A full exclusivity date requires:
- the patent’s issue date and filing date,
- any PTA adjustments,
- whether maintenance fees were paid,
- and whether there are later blocking or continuation patents.
Because that information is not included in your input, a precise “lose exclusivity” date cannot be stated accurately here.
What patent expiration dates and overlapping claims matter most for entry planning?
No overlapping patent set can be enumerated without the patent family data and the related prosecution history.
Given only the claims provided, the most practical overlap zones for planning are:
- formulation and dosage-unit claims (claims 3-8)
- medical use dosing regimen (claims 9-14)
Any later patents in the same family or related families that add:
- controlled-release,
- new salts,
- new dosing regimens,
- or alternative dosing for specific patient subsets,
could shift the blocking position for generic or license entry. But that cannot be mapped without the patent set.
How many patents cover the same antidepressant mechanism and compound family?
The count cannot be computed from the provided input. A coverage “count” requires:
- identifying the complete family,
- related continuations/divisionals,
- and any citation-derived related claims across multiple assignees.
With only US 3,885,046 claim text supplied, a quantified landscape cannot be produced.
What is the Paragraph IV challenge risk for products using these APIs or salts?
Paragraph IV filing risk depends on whether an Orange Book-listed reference product exists for:
- antidepressant-effective use of these APIs, and
- matching dosage forms and strengths covered by claims 3-8,
as well as whether the labeling dosing regimen falls within claims 10-11.
From the claim text alone, key “risk drivers” are clear:
- If a generic seeks approval for a product using m-chloro-α-t-butylaminopropiophenone (including acid addition salts), claim 1 and claim 9 supply method and composition coverage.
- If it markets tablets/capsules/sterile solutions/suspensions within the unit mg ranges, claims 3-8 and related composition dependencies are direct obstacles.
- If it relies on a dosing regimen within 10–100 mg/kg oral/rectal or 5–50 mg/kg parenteral, method claims 10-11 become a label-anchored risk.
A Paragraph IV risk assessment that turns into a litigation forecast, however, requires the listed reference product(s) and label.
What generic entry risks exist for m-chloro-α-t-butylaminopropiophenone hydrochloride tablets in the 15–500 mg band?
If an entrant markets a tablet containing 15–500 mg of m-chloro-α-t-butylaminopropiophenone hydrochloride:
- claim 8 is directly implicated (tablet + exact salt + unit-strength band),
- claim 1 is still implicated through “acid addition salt” coverage plus antidepressant-effective composition concept,
- and method dosing claims can be asserted based on the label or actual practice.
If a competitor instead uses a different salt:
- claim 8 may not read,
- but claim 5 and claim 1 can still capture “acid addition salt” formulations.
If a competitor instead markets strengths outside 15–500 mg:
- claim 8 may be evaded,
- but claim 3 may still capture oral/rectal discrete units if within 15–500 mg and otherwise fitting.
How does US 3,885,046 compare with other antidepressant patents targeting different chemical classes?
On the record implied by your claim text, US 3,885,046 is chemical-compound-use centric rather than technology platform centric:
- It covers specific substituted propiophenone amines and their acid salts.
- It covers dosage-unit strength ranges and mammal dosing regimens for depression.
By contrast, later antidepressant estates in other chemical families often emphasize:
- distinct salt forms, polymorphs, or crystal forms,
- prodrug designs,
- or delivery systems.
Without the broader comparative dataset, a precise cross-family comparison cannot be executed here.
Who are the key players that could license, challenge, or settle around this patent?
No assignee, prosecution parties, or litigation parties are included in your input. A reliable list of challengers and likely license counterparties requires the patent’s bibliographic data and enforcement history.
Orange Book status: what FDA listings correspond to these claims?
An Orange Book mapping cannot be performed because:
- no reference drug name(s) are provided in your input,
- and no FDA application numbers are provided.
The patent’s enforceability against generics depends on which drug is Orange Book-listed, what active ingredient and salt form is listed, and what dosage forms and strengths are covered by the listed labeling.
Method-of-use enforcement: will labeling and dosing fall into claims 9–14?
Claim 9: general mammal method
- “treating a depressed state in mammals” using “administration of an effective antidepressive dose” of the compound.
This is broad and can be asserted as a “use” tether, particularly if a label or clinical protocol instructs use of the specific compound.
Claim 10 and 11: dosing band constraints
- Oral/rectal method (10): 10–100 mg/kg (base).
- Parenteral method (11): 5–50 mg/kg (base).
If a product’s labeled dosing stays within these windows, method-of-use infringement risk increases. If dosing shifts materially outside them, claim coverage weakens.
Claim 12–14: human-specific language
- claim 12: administering to a human an effective antidepressant dose of m-chloro-α-t-butylaminopropiophenone hydrochloride.
- claim 13–14: dependent human mammal definitions tied to claims 10–11.
These add litigation leverage when the accused product is the hydrochloride salt and the dosing matches.
Key claims map: what each claim covers (scope in one glance)
| Claim |
Claim type |
Core coverage |
Key quantitative limits |
Enforcement “hooks” |
| 1 |
Composition |
Pharmaceutical composition for depressed state using compound of general formula, incl. antidepressant-effective amount |
None in text provided |
Broad composition coverage; salt inclusion via acid addition language appears in dependent claims |
| 2 |
Composition (dependent) |
Same as claim 1 with concentration |
compound/salt 5–95% by weight |
Narrower concentration band for composition product design |
| 3 |
Composition (dependent) |
Oral/rectal discrete dosage unit |
15–500 mg per unit (as base) |
Strong product-strength gate for enteral/rectal formats |
| 4 |
Composition (dependent) |
Parenteral discrete dosage unit |
7.5–250 mg per unit (as base) |
Strong product-strength gate for injectable formats |
| 5 |
Dosage form |
Tablet with antidepressant-effective amount of named API or acid addition salt + carrier |
None in text provided |
Covers tablets even without unit mg limitation (unless other dependent claims asserted) |
| 6 |
Dosage form |
Capsule with named API or acid addition salt + carrier |
None in text provided |
Capsule-specific capture |
| 7 |
Dosage form |
Sterile solution/suspension for parenteral with named API or acid addition salt + carrier |
None in text provided |
Captures injectable sterile liquid/suspension class |
| 8 |
Dosage form (dependent) |
Tablet with specific salt |
15–500 mg of hydrochloride per tablet |
Most precise enforceable formulation claim |
| 9 |
Method |
Mammal method for depression using compound |
None in text provided |
Broad method-of-use tether |
| 10 |
Method (dependent) |
Oral/rectal dosing regimen |
10–100 mg/kg (base) |
Label/practice dosing window |
| 11 |
Method (dependent) |
Parenteral dosing regimen |
5–50 mg/kg (base) |
Injectable dosing window |
| 12 |
Method (dependent) |
Human dosing of hydrochloride |
None in text provided |
Human-specific method tether for hydrochloride |
| 13 |
Method (dependent) |
Human mammal definition for claim 10 |
None additional |
Clarifies human applicability for oral/rectal window |
| 14 |
Method (dependent) |
Human mammal definition for claim 11 |
None additional |
Clarifies human applicability for parenteral window |
Key Takeaways
- US 3,885,046 is anchored on antidepressant compositions and depression treatment methods using m-chloro-α-t-butylaminopropiophenone and m-fluoro-α-t-butylaminopropiophenone, including acid addition salts, with explicit coverage of tablets, capsules, and sterile parenteral solution/suspension.
- The patent’s highest-friction barriers for generic or follow-on products are the quantitative unit-dose bands (notably 15–500 mg oral/rectal units and the 15–500 mg tablet band for the hydrochloride salt, claim 8).
- Method-of-use enforcement depends on whether the accused product’s labeling or administered regimen tracks the mg/kg dose windows in claims 10–11 and involves the hydrochloride salt for the human method claims (claims 12–14).
- The claim set provided does not extend into release technologies, polymorphs, manufacturing methods, or diagnostic strategies, limiting the patent’s ability to block design-arounds that switch those aspects while keeping API/salt outside the claim-defined species.
FAQs
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Do claims 1 and 9 cover acid addition salts generally, or only hydrochloride?
From the claim text provided, they cover pharmaceutically acceptable acid addition salts generally, while hydrochloride is explicitly singled out in claims 8 and 12.
-
Can a tablet using a different acid salt avoid claim 8?
Claim 8 is specifically for m-chloro-α-t-butylaminopropiophenone hydrochloride. Using a different acid salt may avoid the specific-salt requirement, but claim 5 and claim 1 can still capture acid addition salt formulations.
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What dosing band is claimed for oral or rectal administration in mammals?
Claim 10 recites 10 to 100 mg/kg (calculated as base) for oral or rectal administration.
-
What parenteral unit strength ranges are claimed?
Claim 4 recites 7.5 to 250 mg per parenteral discrete dosage unit, calculated as base.
-
What is the most product-specific claim in the set you provided?
Claim 8 is the tightest: tablet + hydrochloride salt + 15–500 mg per tablet + pharmaceutically acceptable carrier.
References
- U.S. Patent 3,885,046.
