United States Patent 5,186,925: Scope, Claim Construction, Expiration, and Nitroglycerin Pump-Spray Patent Landscape

U.S. Patent No. 5,186,925 covers a nitroglycerin pump spray with a narrowly defined liquid vehicle: 10% to 40% ethyl alcohol and 60% to 90% synthetic or natural fatty oils, together with 0.2% to 3.5% nitroglycerin and no more than 3% flavoring agents or antioxidants. The patent issued on February 16, 1993, and its enforceable term has expired. The claims therefore have historical and freedom-to-operate relevance but do not presently create an enforceable U.S. patent barrier.

What does U.S. Patent 5,186,925 protect?

The patent protects a pharmaceutical composition and delivery format, not nitroglycerin as a molecule and not every nitroglycerin spray.

The independent claim requires all of the following elements:

Claim element	Required scope
Dosage form	Nitroglycerin pump spray
Nitroglycerin concentration	0.2% to 3.5% by weight
Additives	Up to 3% by weight
Permitted additives	Flavoring agents and antioxidants
Ethyl alcohol	10% to 40% by weight of the liquid phase
Fatty oils	60% to 90% by weight of the liquid phase
Fatty-oil category	Synthetic or natural fatty oils

Claim 1 is a combination claim. A competing product would have needed to practice each limitation to fall within its literal scope during the patent term. A product using nitroglycerin outside the 0.2% to 3.5% range, a liquid phase outside the alcohol-to-oil ranges, or a different delivery system could avoid literal infringement.

The claim does not require a particular pump mechanism, spray volume, container material, metering chamber, propellant, indication, or clinical dosage. The protection is concentrated in the formulation and its use in a pump-spray presentation.

What is the claim hierarchy of Patent 5,186,925?

Claims 2 through 5 narrow claim 1 through progressively more specific vehicle limitations.

Claim	Added limitation	Commercial significance
1	10% to 40% ethanol and 60% to 90% fatty oils	Broadest composition claim
2	15% to 30% ethanol and 70% to 85% fatty oils	Preferred vehicle range
3	About 20% ethanol and about 80% fatty oils	Approximate target formulation
4	Saturated natural oil or C8-C12 fatty-acid triglyceride	Defines oil classes
5	Saturated natural oil is rape oil	Narrowest express embodiment

Claim 2 is narrower than claim 1 because every formulation within claim 2 must also satisfy claim 1. Claim 3 is narrower still, although “about 20%” and “about 80%” would require interpretation based on the specification, examples, manufacturing tolerances, and ordinary pharmaceutical formulation practice.

Claims 4 and 5 add oil identity limitations. Claim 4 covers either a saturated natural oil or a triglyceride made from C8-C12 fatty acids. Claim 5 is limited to rape oil as the saturated natural oil.

How should the concentration ranges be interpreted?

The percentages are weight percentages, and the claim distinguishes between total composition and the liquid phase.

Nitroglycerin must comprise 0.2% to 3.5% by weight of the spray composition. Additives may comprise up to 3% by weight. The ethanol and fatty-oil ranges apply to the liquid phase, not necessarily to the entire finished composition.

That distinction matters. A formulation may contain nitroglycerin and additives outside the ethanol-oil calculation while still meeting the vehicle limitations. The patent does not state in the supplied claims whether the liquid phase percentages are calculated before or after addition of nitroglycerin and additives. The specification and prosecution history would control disputed construction.

The ranges are inclusive on their face. A composition with 10% ethanol and 90% fatty oils could meet claim 1, subject to the other limitations. A composition with 9.9% ethanol or 40.1% ethanol would fall outside the literal ethanol range, although an equivalent formulation could raise a doctrine-of-equivalents issue during the patent term.

What formulations are protected by Patent 5,186,925?

The patent is directed to nitroglycerin dissolved or dispersed in an alcohol-and-fatty-oil vehicle used in a pump spray. The most commercially relevant formulation profile is a low-strength nitroglycerin spray with approximately 20% ethanol and 80% fatty oil.

Potentially covered formulations include:

Nitroglycerin at 0.2% to 3.5% by weight.
Ethanol at 10% to 40% of the liquid phase.
Natural oils within the claimed category.
Synthetic fatty oils.
Medium-chain triglycerides based on C8-C12 fatty acids.
Formulations containing limited flavoring agents.
Formulations containing limited antioxidants.
Pump-spray products using a saturated natural oil, including the claim 5 rape-oil embodiment.

The claim does not expressly require peppermint flavor, a particular antioxidant, or a specific triglyceride composition. Those ingredients could be relevant only if they fall within the claim’s permitted additive or fatty-oil categories and concentration limits.

What products are technically close to the claimed formulation?

Nitroglycerin pump sprays historically used alcohol and medium-chain triglyceride vehicles. A representative product is Nitrolingual Pumpspray, marketed by Pohl-Boskamp and approved in the United States for acute relief of an angina attack and prophylactic use before activities expected to cause angina. The FDA labeling identifies nitroglycerin as the active ingredient and describes a metered pump-spray product delivering approximately 0.4 mg per spray (U.S. Food and Drug Administration, n.d.-a).

A 0.4 mg dose delivered in a spray weight of approximately 200 mg corresponds to roughly 0.2% nitroglycerin by weight. That concentration is at the lower boundary of claim 1. A formulation using medium-chain triglycerides and approximately 20% ethanol would also be technically close to claims 2 through 4, depending on the exact formulation and calculation method.

Technical similarity does not establish infringement. The accused product would need to satisfy the complete claim, including the claimed additive ceiling, the liquid-phase calculation, and the relevant oil definition.

When did U.S. Patent 5,186,925 expire?

U.S. Patent 5,186,925 issued on February 16, 1993. It was a pre-Uruguay Round Agreements Act patent, for which the ordinary term was 17 years from grant, subject to any terminal disclaimer, patent-term adjustment, or other term-specific event.

On the ordinary term calculation, the patent expired on February 16, 2010. No enforceable exclusionary right remains under the patent.

Event	Date
U.S. patent grant	February 16, 1993
Ordinary 17-year expiration	February 16, 2010
Current status	Expired by term

The expiration date eliminates current infringement risk under this patent. It does not eliminate potential relevance of related continuation, divisional, foreign, or later-filed patents directed to the same product, manufacturing process, container, or method of treatment.

What is the Orange Book status of Patent 5,186,925?

Patent 5,186,925 should not be treated as a current Orange Book barrier for nitroglycerin pump-spray approval. The patent is expired, and expired patents do not block approval or commercial launch.

The FDA Orange Book identifies patents submitted by sponsors for approved drug products and records patent-use codes and expiration information. The relevant approved product category includes nitroglycerin sublingual spray, including Nitrolingual Pumpspray under an approved new drug application held by Pohl-Boskamp or its U.S. affiliate, depending on the applicable FDA listing period (U.S. Food and Drug Administration, n.d.-b).

The practical conclusions are:

Patent 5,186,925 cannot support a current Paragraph IV enforcement action.
It cannot delay approval through a live 30-month stay.
It cannot prevent an ANDA applicant from launching after satisfying applicable FDA requirements.
Any current Orange Book issue would arise from a different, unexpired patent or regulatory exclusivity period.

Does Patent 5,186,925 create a Paragraph IV risk?

No. A Paragraph IV certification is relevant to an unexpired patent listed in the Orange Book. Because Patent 5,186,925 expired in 2010, it cannot independently support a Paragraph IV challenge or a 30-month stay.

A generic applicant seeking approval for a nitroglycerin pump spray could still face:

A different unexpired formulation patent.
A method-of-use patent.
A device or container patent.
A manufacturing-process patent.
Regulatory exclusivity unrelated to Patent 5,186,925.
Product-specific FDA requirements concerning dose delivery, content uniformity, stability, and container closure.

The patent’s expiration means that the formulation concept described in its claims is generally available for use, subject to other rights.

What method-of-use protection does the patent provide?

The supplied claims contain no method-of-treatment limitation. They claim a product: a nitroglycerin pump spray with specified formulation characteristics.

The patent therefore does not require:

Treatment of angina.
Prevention of angina before exercise.
A particular dosing regimen.
Administration under the tongue.
Use in acute coronary syndrome.
A particular patient population.

A separate method-of-use patent could protect administration of nitroglycerin for a defined indication or dosing schedule. Such a patent would be legally distinct from Patent 5,186,925 and would require separate analysis.

What manufacturing and intellectual-property barriers remain?

The expired patent removed the principal formulation barrier disclosed in the claims, but commercial entry still requires pharmaceutical development and FDA compliance.

Relevant technical barriers include:

Nitroglycerin content uniformity at low concentration.
Control of dose per pump actuation.
Compatibility of nitroglycerin with elastomers, seals, valves, and container materials.
Stability under light, heat, and oxygen exposure.
Control of evaporation of ethanol.
Consistency of spray pattern and droplet size.
Packaging that limits leakage and active loss.
Safe handling of a high-energy nitrate during manufacturing.
Validation of microbial and chemical stability.
Demonstration of bioavailability or therapeutic equivalence where required.

Nitroglycerin is a potent vasodilator, and the product must deliver a reproducible dose. For an ANDA or other abbreviated pathway, formulation similarity alone may not resolve device-performance and product-quality requirements.

Which companies are challenging or licensing this patent?

There is no current competitive or litigation value in identifying a challenger to Patent 5,186,925 because the patent expired more than a decade ago. A Paragraph IV challenge is no longer operative against it.

The patent appears to have been associated with the Pohl-Boskamp nitroglycerin pump-spray technology and product family. Any historical assignment, license, or litigation analysis should distinguish:

The named patent owner.
The approved-product sponsor.
The manufacturer.
Any distributor or licensee.
Later patents covering the product or its delivery system.

Patent 5,186,925 itself does not establish that every product sold by Pohl-Boskamp was protected only by this patent, nor that the patent was the sole basis for any commercial license.

How strong was the patent estate for nitroglycerin pump sprays?

As an individual patent, Patent 5,186,925 had meaningful formulation specificity but limited breadth.

Strength factor	Assessment
Active ingredient	Narrowly limited to nitroglycerin
Dosage form	Limited to pump spray
Vehicle	Limited to ethanol plus fatty oils
Concentration range	Broad enough to cover common low-dose formulations
Oil definition	Broad in claim 1, narrowed in claims 4 and 5
Method-of-use scope	None in the supplied claims
Device scope	Minimal
Manufacturing scope	None in the supplied claims
Current enforceability	None after expiration

The patent’s commercial value likely arose from covering a practical formulation and delivery format rather than from broad ownership of nitroglycerin therapy. Its claims could have been vulnerable to design-around strategies using different solvent systems, alternative oil vehicles, non-pump delivery, or concentrations outside the claimed ranges.

How does Patent 5,186,925 compare with modern generic-entry risk?

The patent presents no current generic-entry risk because its term ended in 2010. The principal present-day risk is regulatory and operational rather than patent-based.

A competing manufacturer can generally develop a nitroglycerin pump spray using the disclosed ethanol-and-fatty-oil concept without infringing this expired patent. The manufacturer must still evaluate:

Current Orange Book listings.
FDA product-specific guidance.
Reference-listed-drug requirements.
Device compatibility.
Product quality and stability.
Trade dress and trademark rights.
Later patents owned by the product sponsor or device suppliers.
Foreign patent rights in target markets.

U.S. freedom to operate does not establish freedom to operate in Europe, Canada, Japan, China, or other jurisdictions. Any corresponding foreign patent family would have expired no later than the applicable national term, but exact dates depend on priority, filing, grant, patent-term adjustments, and national rules.

What is the commercial exposure associated with this patent?

Patent 5,186,925 no longer creates direct revenue exposure for the patent owner. Its expiration permits competition based on the claimed formulation, assuming no later enforceable rights apply.

Commercial exposure may still exist for the branded product through:

Brand recognition.
Physician and patient familiarity.
Established manufacturing controls.
FDA-approved product history.
Distribution relationships.
Device reliability.
Switching costs at pharmacies and hospitals.
Trademark and trade-dress protection.

Those factors can preserve commercial value after patent expiry, but they are not patent exclusivity.

Key Takeaways

U.S. Patent 5,186,925 claims a nitroglycerin pump spray with 0.2% to 3.5% nitroglycerin and an ethanol-fatty-oil liquid phase.
Claim 1 is the broadest claim; claims 2 through 5 progressively narrow ethanol, oil, and natural-oil composition.
Claims 4 and 5 are particularly directed to C8-C12 fatty-acid triglycerides and rape oil.
The patent issued on February 16, 1993, and ordinarily expired on February 16, 2010.
The patent has no current enforceable U.S. exclusionary effect.
It cannot independently support a current Paragraph IV challenge or 30-month FDA stay.
The principal remaining barriers are later patents, FDA requirements, manufacturing controls, device performance, and commercial branding.
A current freedom-to-operate review must examine later U.S. patents and current Orange Book listings for the relevant nitroglycerin product.

Frequently Asked Questions

Is nitroglycerin itself patented by U.S. Patent 5,186,925?

No. The patent claims a particular nitroglycerin pump-spray composition. It does not claim nitroglycerin as a chemical compound.

Does the patent cover all nitroglycerin sprays?

No. It requires a pump spray and the specified nitroglycerin, ethanol, fatty-oil, and additive limitations.

Can a generic manufacturer use the claimed 20% ethanol and 80% oil formulation today?

Patent 5,186,925 does not prevent that use because the patent expired in 2010. Other later patents, regulatory requirements, or non-patent rights must be assessed separately.

Does a nitroglycerin sublingual tablet fall within the claims?

No. The claims require a pump spray. A tablet, capsule, ointment, infusion, or other dosage form does not meet that dosage-form limitation.

Does expired Patent 5,186,925 eliminate all exclusivity for Nitrolingual Pumpspray?

No. It eliminates exclusivity under this patent only. Trademark rights, regulatory requirements, later patents, confidential manufacturing know-how, and commercial advantages may remain.

References

U.S. Food and Drug Administration. (n.d.-a). Nitrolingual Pumpspray prescribing information. https://www.accessdata.fda.gov/

U.S. Food and Drug Administration. (n.d.-b). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files

United States Patent and Trademark Office. (1993). U.S. Patent No. 5,186,925, Nitroglycerin pump spray. https://patents.google.com/patent/US5186925A/en

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Germany	4007705	Mar 10, 1990

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	125703	⤷ Start Trial
Canada	2037487	⤷ Start Trial
Germany	4007705	⤷ Start Trial
Germany	59106106	⤷ Start Trial
Denmark	0448961	⤷ Start Trial
European Patent Office	0448961	⤷ Start Trial
Spain	2075908	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,186,925

Summary for Patent: 5,186,925