US Patent 3,987,200: Scope, Claims, Expiration, and Dobutamine Patent Landscape

US Patent 3,987,200 covers the use of selected N-substituted phenethylamines, most importantly dobutamine hydrochloride, to increase cardiac contractility in mammals with acutely depressed cardiac function. The patent is expired. Its method claims no longer create a U.S. exclusivity barrier, and the patent does not provide current protection for dobutamine products, formulations, manufacturing processes, or hospital-use presentations.

What drug does US Patent 3,987,200 protect?

The principal drug identified in the claims is dobutamine hydrochloride, chemically described in claim 3 as:

3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-1-methyl-n-propyl]-β-phenethylamine hydrochloride.

Claim 4 separately covers the levo isomer. The patent therefore addresses both the racemic compound and a specified stereoisomer, along with related catecholamine structures.

Patent element	Scope
U.S. patent	3,987,200
Patent subject	Method of increasing cardiac contractility
Core therapeutic use	Treatment of acutely depressed cardiac contractility
Drug most closely associated with claim set	Dobutamine hydrochloride
Dosage rate	0.5 to 10 micrograms/kg/minute
Covered patients	Warm-blooded mammals
Claim type	Method-of-treatment claims
Salt coverage	Pharmaceutically acceptable acid-addition salts with mineral acids
Patent status	Expired
Current U.S. blocking effect	None

The claims are directed to administration rather than to ownership of the molecular structure in every possible context. The patent does not, based on the supplied claims, independently claim:

Dobutamine as a composition of matter;
A pharmaceutical formulation;
An injectable dosage form;
A manufacturing process;
A stability package;
A container or delivery device;
A specific hospital protocol outside the claimed dosing range.

The method claims were commercially important because dobutamine is administered intravenously for short-term inotropic support in patients with cardiac decompensation.

What compounds are covered by claim 1?

Claim 1 is a Markush method claim. It covers administration of compounds having the specified phenethylamine framework, subject to substituent and chain-length limitations.

The claim permits:

R and R1 to be hydrogen or methyl;
R2 and R3 to be hydrogen or hydroxy;
At least one of R2 and R3 to be hydroxy;
n to be 1 or 2;
Pharmaceutically acceptable mineral-acid addition salts.

The claim also imposes a special restriction for the n=2, R2=hydrogen, R3=hydroxy configuration: one of R or R1 must be hydrogen and the other must be methyl.

The result is a genus covering several catecholamine-like compounds with different combinations of:

N-side-chain length;
Alpha-methyl substitution;
Beta-methyl substitution;
One or two phenolic hydroxy groups;
Acid-addition salt forms.

The therapeutic limitation is essential. Claim 1 does not cover merely making, selling, or possessing every compound within the chemical genus. It requires administration to a warm-blooded mammal suffering from acutely depressed cardiac contractility at the stated infusion rate.

How do claims 2 through 8 narrow the patent scope?

Claim 2 narrows claim 1 by imposing additional structural restrictions. It excludes certain combinations that would otherwise fall within the broad genus.

The principal limitations are:

Where n=2 and both R2 and R3 are hydroxy, R1 must be hydrogen.
Where n=1, R2 is hydrogen, and R3 is hydroxy, both R and R1 must be hydrogen.
The compound must remain within the salt and substituent limitations of claim 1.

Claims 3 through 8 then identify individual compounds.

Claim	Claimed compound or category	Commercial relevance
1	Broad genus administered at 0.5-10 micrograms/kg/minute	Broadest method claim
2	Restricted genus with additional substituent limitations	Intermediate scope
3	3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-1-methyl-n-propyl]-β-phenethylamine hydrochloride	Dobutamine hydrochloride, generally understood as the racemic product
4	Levo-3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-1-methyl-n-propyl]-β-phenethylamine hydrochloride	Levo stereoisomer
5	3,4-dihydroxy-N-[3-(3-hydroxyphenyl-n-propyl]-β-phenethylamine hydrochloride	Meta-hydroxy phenyl analogue
6	3,4-dihydroxy-N-[3-(4-hydroxyphenyl)-n-propyl]-α-methyl-β-phenethylamine hydrochloride	Alpha-methyl analogue
7	3,4-dihydroxy-N-[2-(3,4-dihydroxyphenyl)ethyl]-β-phenethylamine	Tetrahydroxy phenethylamine analogue
8	3,4-dihydroxy-N-[3-(3,4-dihydroxyphenyl)-n-propyl]-β-phenethylamine hydrochloride	Additional tetrahydroxy analogue

Claims 3 and 4 carry the greatest commercial significance. Claims 5 through 8 are narrower species claims and appear directed to research compounds or analogues rather than the principal marketed dobutamine product.

What is the legal scope of the dobutamine claim?

Claim 3 requires all of the following:

The claimed chemical structure;
Administration to a mammal;
Treatment of acutely depressed cardiac contractility;
Administration within the claimed rate range inherited from claim 1;
The hydrochloride salt identified in the claim.

A product manufacturer would not necessarily infringe claim 3 merely by selling dobutamine hydrochloride. Direct method infringement would generally require carrying out, directing, or inducing the claimed administration method. The analysis would depend on the product labeling, promotional conduct, actual administration, and applicable U.S. patent law.

Claim 4 is narrower because it requires the levo isomer. A racemic dobutamine product would not automatically satisfy a claim limited to the levo form unless the claim construction and product composition established that the claimed stereoisomer was present and administered in the required manner.

The claims also contain a potential interpretation issue: the chemical structures were originally presented as patent drawings, while the text supplied here replaces them with image placeholders. Exact stereochemical and positional analysis must therefore be based on the issued patent figures and specification, not only the transcribed text.

When did US Patent 3,987,200 expire?

US Patent 3,987,200 issued on October 19, 1976. It is a pre-June 8, 1995 patent and therefore generally falls under the former 17-year term measured from issuance, subject to any patent-specific adjustment or disclaimer. On that basis, the patent expired approximately on October 19, 1993.

Event	Date
U.S. patent issuance	October 19, 1976
Standard pre-1995 patent term	17 years from issuance
Approximate expiration	October 19, 1993
Current status	Expired
Current enforceability	No enforceable exclusionary term

The expiration date means that the claims cannot presently block U.S. generic manufacture, sale, labeling, or administration of dobutamine based on this patent. The patent’s historical value remains relevant for understanding the origin of dobutamine’s cardiac contractility indication.

What is the FDA regulatory status of dobutamine?

Dobutamine hydrochloride is an established small-molecule cardiovascular drug administered primarily by intravenous infusion. FDA-approved labeling describes it as a direct-acting inotropic agent used for short-term treatment of cardiac decompensation caused by depressed contractility, including situations associated with organic heart disease or cardiac surgery.[2]

Key regulatory characteristics include:

Regulatory issue	Status
FDA pathway	Conventional small-molecule approval and ANDA pathway
Active ingredient	Dobutamine hydrochloride
Main dosage form	Intravenous injection or infusion concentrate/solution
Primary therapeutic effect	Positive inotropy
Biologic status	Not a biologic
Biosimilar pathway	Not applicable
Pediatric exclusivity relevance	No current patent effect
Orphan-drug exclusivity relevance	Not the source of current market exclusivity
Patent linkage	No active protection from US 3,987,200

Dobutamine is not subject to biosimilar competition because biosimilars apply to biological products, not conventional chemically synthesized drugs. Competition occurs through generic injectable products and authorized or branded hospital products.

What is the Orange Book status of dobutamine?

Dobutamine products may be listed in the FDA Orange Book through approved new drug applications and related generic applications. The Orange Book is the relevant FDA database for listed patents and regulatory exclusivity for approved small-molecule products.[3]

US Patent 3,987,200 should not be treated as an active Orange Book patent. Its expiration predates the current commercial generic market by decades. The patent also appears, based on the supplied claims, to be a historical method patent rather than a current formulation or manufacturing patent.

For current diligence, the relevant questions are:

Whether any active patent is listed against a particular dobutamine NDA;
Whether a listed patent covers a formulation, delivery system, or method of use;
Whether the generic applicant certified under Paragraph IV;
Whether the NDA holder has a 30-month stay or related patent litigation;
Whether any regulatory exclusivity remains.

The expired 1976 patent does not create a current Paragraph IV target with commercial blocking power.

Are there Paragraph IV challenges to US Patent 3,987,200?

A current Paragraph IV challenge to US Patent 3,987,200 would have no practical commercial purpose because the patent is expired. Paragraph IV certifications are used against listed patents that remain in force or whose expiration is relevant to the proposed approval date. An applicant would not need to challenge this patent to launch a dobutamine product today.

Historical generic applicants may have addressed other listed patents or regulatory issues, but the supplied record does not establish a specific Paragraph IV case involving this patent. No present litigation strategy should treat US 3,987,200 as a live patent barrier.

What patent litigation affects dobutamine?

The central patent litigation risk from US 3,987,200 is zero because the patent term has ended. The patent does not support:

A current injunction;
A new Hatch-Waxman 30-month stay;
A damages claim for post-expiration sales;
A launch block against an ANDA product;
A patent-based hospital procurement restriction.

No settlement agreement can extend the enforceable term of an expired patent. Any historical settlement involving dobutamine would have to be evaluated against the specific parties, dates, patents, and launch provisions. The supplied claims alone do not establish such an agreement.

What formulation patents protect dobutamine products?

The supplied claims do not claim a formulation. They claim administration of specified chemical compounds at a specified dose rate.

A separate formulation patent would need to address features such as:

Concentration of dobutamine hydrochloride;
pH adjustment;
Stabilizers or antioxidants;
Diluent selection;
Premixed intravenous bags;
Container compatibility;
Storage temperature;
Light protection;
Delivery-device configuration;
Shelf-life or degradation control.

Those rights would be distinct from US 3,987,200. A manufacturer could have pursued formulation or manufacturing patents independently, but the historical method patent itself does not establish such protection.

How strong is the patent estate for dobutamine?

The current U.S. patent estate is weak from an exclusivity perspective because the principal identified patent expired in 1993 and the product is an established generic injectable.

Estate category	Assessment
Core composition patent	Not established by the supplied claims
Method-of-use patent	US 3,987,200, expired
Species claim to dobutamine	Claim 3, expired
Stereoisomer claim	Claim 4, expired
Formulation patent	Not established by this patent
Manufacturing patent	Not established by this patent
Device patent	Not established by this patent
Biosimilar protection	Not applicable
Current blocking strength	None from US 3,987,200

The original patent had meaningful historical scope because it combined a cardiac-contractility indication with a defined infusion-rate range and a broad chemical genus. Its present commercial strength is zero as an enforceable patent asset.

What generic launch risks exist for dobutamine?

A generic dobutamine launch is not exposed to US 3,987,200. Current launch risks are more likely to involve:

FDA approval requirements for sterile injectable products;
Aseptic manufacturing compliance;
Container-closure integrity;
Supply of active pharmaceutical ingredient;
Sterility and endotoxin control;
Injectable-product shortages;
Hospital contracting;
Product liability;
Any unexpired patent listed against a specific NDA;
Manufacturing-site inspection findings.

These are regulatory and operational barriers rather than exclusivity barriers. Dobutamine’s injectable presentation can make manufacturing and quality compliance more difficult than for a conventional oral tablet, but that difficulty does not restore patent protection.

Which companies compete in the dobutamine market?

The market consists primarily of generic injectable manufacturers, hospital suppliers, and distributors. Competition is based on:

FDA-approved injectable presentation;
Supply reliability;
Contract pricing;
Hospital formulary access;
Shortage performance;
Concentration and package size;
Ready-to-use versus pharmacy-compounded presentations.

Brand identity is less important than procurement economics in this category. The supplied patent does not identify a current exclusive manufacturer, and its expiration permits multiple suppliers to compete without licensing the patent owner.

Does US Patent 3,987,200 create revenue exposure?

No current revenue stream can be attributed to this patent as an enforceable right. The patent expired approximately three decades ago. It cannot generate present royalty income through ordinary patent licensing, and it cannot support an infringement claim against current generic dobutamine sales.

Its historical commercial value was tied to the development and launch of dobutamine, not to current exclusivity. Any valuation of a dobutamine business should separate:

Product sales and hospital contracts;
Manufacturing capacity;
Regulatory approvals;
Supply-chain position;
Current patents and applications;
Historical patents such as US 3,987,200.

The historical patent should be assigned no current blocking value in a U.S. patent-asset valuation.

Key Takeaways

US Patent 3,987,200 covers methods for increasing cardiac contractility using a defined genus of substituted phenethylamines.
Claim 3 is the key commercial claim because it identifies dobutamine hydrochloride.
Claim 4 separately addresses the levo isomer.
The patent claims treatment methods, not a complete formulation, manufacturing process, or delivery device.
The patent issued on October 19, 1976, and its standard pre-1995 term expired approximately on October 19, 1993.
The patent is not a current barrier to generic dobutamine approval or launch.
No biosimilar pathway applies because dobutamine is a conventional small molecule.
Current competition is driven by sterile injectable manufacturing, FDA compliance, supply, and hospital contracting.
Any active protection for a particular dobutamine product would have to come from separate, unexpired patents or regulatory rights, not US 3,987,200.

FAQs

Is dobutamine hydrochloride covered by US Patent 3,987,200?

Yes. Claim 3 expressly identifies dobutamine hydrochloride in a method of increasing cardiac contractility. The claim is expired.

Can a generic company launch dobutamine without licensing the patent owner?

Yes, assuming the company satisfies FDA approval, manufacturing, labeling, and other applicable requirements. US 3,987,200 no longer creates a licensing requirement.

Does the patent cover dobutamine injection as a formulation?

No. The supplied claims cover administration of specified compounds. They do not claim a particular concentration, excipient system, container, or injectable formulation.

Does claim 4 cover levodobutamine?

Claim 4 covers the named levo form of the dobutamine structure. Whether a modern product name such as levodobutamine maps exactly to the claim requires comparison of the marketed product’s stereochemistry with the issued patent structure.

Is a Paragraph IV certification required for this patent?

No current Paragraph IV challenge is needed against US 3,987,200 because the patent has expired. Paragraph IV analysis would focus on any other unexpired patent listed for the relevant FDA-approved product.

Sources

U.S. Patent No. 3,987,200. (1976). Method of increasing cardiac contractility. U.S. Patent and Trademark Office.
U.S. Food and Drug Administration. (n.d.). Dobutamine hydrochloride injection prescribing information. FDA.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
35 U.S.C. § 154. Patent term.
21 U.S.C. § 355. New drug applications and abbreviated applications.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	203822	⤷ Start Trial
Austria	323719	⤷ Start Trial
Australia	472734	⤷ Start Trial
Australia	5438573	⤷ Start Trial
Belgium	798051	⤷ Start Trial
Bulgaria	23001	⤷ Start Trial
Canada	1018188	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 3,987,200

Summary for Patent: 3,987,200