United States Patent 4,863,970: Claim Scope, Expiration, and Transdermal Formulation Patent Landscape

U.S. Patent No. 4,863,970 protects a topical pharmaceutical composition using oleic-acid-related penetration enhancers with ethanol, propanol, or isopropanol. The broadest claim covers a drug-containing vehicle with specified concentration ranges and excludes diols and N-cyclic solvents. The patent issued September 5, 1989, and its enforceable term appears to have expired on September 5, 2006, under the pre-1995 17-year-from-grant term applicable to the patent. The patent therefore presents no current blocking right, although later patents may protect particular drugs, dosage forms, delivery systems, or commercial formulations using similar excipients.

What does U.S. Patent 4,863,970 protect?

The patent protects a topical composition that combines four core elements:

Required element	Claim requirement
Pharmaceutical agent	A safe and effective amount of an active pharmaceutical agent
Application route	Topical application
Cell-envelope disordering compound	Oleic acid, oleyl alcohol, glycerol esters of oleic acid, or mixtures
Lower alkanol	Ethanol, propanol, isopropanol, or mixtures
Optional diluent	Water, polypropylene glycol, polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone, mineral oil, silicone oil, ethylene-vinyl acetate polymers, or similar low-molecular-weight polymers
Exclusions	Diols and N-cyclic solvents
Vehicle concentration	Generally 50% to 99.99% of the composition under dependent claims
Active-agent concentration	Generally 0.01% to 30% under the narrower claims

The central technical concept is a lipid-disordering enhancer combined with a lower alcohol. The claimed excipients are intended to disrupt the lipid organization of the outer skin barrier and improve drug penetration.

The claims do not require a patch, reservoir, adhesive layer, backing layer, particular drug, disease indication, release profile, or device structure.

How broad is claim 1 of U.S. Patent 4,863,970?

Claim 1 is the principal composition claim and has a broad Markush structure. It covers a topical pharmaceutical composition consisting essentially of:

An active pharmaceutical agent;
A penetration-enhancing vehicle;
One or more specified cell-envelope disordering compounds at 1% to 95% by weight;
Ethanol, propanol, or isopropanol at 5% to 75% by weight; and
An optional inert diluent at 0% to 45% by weight.

The phrase “consisting essentially of” is important. It generally permits additional ingredients that do not materially alter the basic and novel characteristics of the claimed formulation, while excluding ingredients that materially change that combination. The claim expressly makes the vehicle exclusive of diols and N-cyclic solvents.

A formulation containing oleic acid and ethanol would fall within the principal chemical concept if the remaining limitations were satisfied. A formulation containing propylene glycol as a penetration enhancer presents a materially different issue because propylene glycol is a diol and is expressly excluded from the vehicle.

The claim is broad as to the active pharmaceutical agent. It does not limit the composition to analgesics, hormones, anti-inflammatory agents, anesthetics, nicotine, steroids, or any other particular active ingredient.

What concentration ranges are protected?

The patent uses nested concentration limitations.

Claim level	Active agent	Vehicle	Alcohol	Diluent
Claim 1	Not specified	Not specified	5%-75%	0%-45%
Claim 2	Not specified	Not specified	5%-49%	0%-45%
Claim 3	0.01%-50%	50%-99.99%	As in claim 2	0%-45%
Claim 5	0.01%-30%	70%-99.99%	As in claim 2	0%-45%
Claim 21	0.01%-30% through dependency	70%-99.99%	20%-49%	0%-45%
Claim 22 onward	0.01%-30% through dependency	70%-99.99%	Usually 5%-49%	1%-45%
Claim 40	0.01%-30% through dependency	70%-99.99%	20%-49%	1%-45% through claim chain

The percentages apply to the composition or vehicle according to the applicable claim language. The specification and prosecution history would control how a court interprets whether the ranges are mutually constrained to a 100% total and how rounding or measurement tolerance is treated.

Which penetration enhancers are covered?

The claims create several principal enhancer branches.

Oleic acid and oleyl alcohol

Claims 6 through 8 cover:

Oleic acid;
Oleyl alcohol; and
Mixtures of oleic acid and oleyl alcohol.

These claims are narrower than claim 1 because they exclude glycerol esters of oleic acid.

Glycerol esters of oleic acid

Claims 9 through 12 identify glycerol esters, including:

Glycerol monooleate;
Glycerol dioleate; and
Glycerol trioleate.

The claim text supplied contains apparent dependency inconsistencies. Claim 11 depends on claim 8, which identifies oleyl alcohol, but then recites glycerol dioleate. Claim 12 depends on claim 7, which identifies oleic acid, but then recites glycerol trioleate. Those dependencies may reflect drafting or transcription errors. The patent’s issued claim set and prosecution history should control the legally operative scope.

Mixed enhancer systems

Claims 13 through 20 cover mixtures involving:

Oleic acid plus one or more glycerol esters;
Oleyl alcohol plus one or more glycerol esters; and
Specific monooleate, dioleate, or trioleate combinations.

The mixed systems are commercially significant because they may capture formulations that use a primary fatty-acid enhancer together with an ester-based co-enhancer.

What formulations are protected by claims 21 through 40?

Claims 21 through 40 add narrower formulation features to the claim 1 architecture.

Claims 21 and 40 require alcohol at approximately 20% to 49% by weight. This limits the claims to relatively alcohol-rich vehicles.

Claims 22 through 40 require an inert diluent at 1% to 45% by weight. The listed diluents include water and both water-soluble and oil-soluble polymeric materials.

The diluent branch is potentially broad, but it remains subject to the exclusion of diols and N-cyclic solvents. This creates formulation-specific construction issues:

Water is expressly listed and is generally within the diluent branch.
Polyethylene glycol is listed, but individual polyethylene glycol products may raise questions because they contain terminal hydroxyl groups and may be characterized differently from simple diols.
Propylene glycol is a diol and falls within the express exclusion when used as part of the penetration-enhancing vehicle.
N-methyl-2-pyrrolidone and related N-cyclic solvents are excluded.
Mineral oil and silicone oil are listed as possible inert diluents, subject to the remaining claim limitations.

Claims 23 through 40 do not create a new technology category. They narrow the original vehicle by adding diluent, specific enhancer identities, alcohol concentration, and active-agent loading.

Does the patent claim a method of treatment or manufacturing process?

No broad treatment or manufacturing protection appears in the supplied claims. The claims are composition claims.

Claim 27 is labeled “A method according to claim 23,” but the remainder of the claim is composition language. That appears to be a formal drafting error or transcription error. It does not independently establish a therapeutic method claim without the issued patent record supporting that interpretation.

The patent does not claim:

Manufacturing oleic acid, oleyl alcohol, or glycerol oleates;
Manufacturing a transdermal patch;
Applying a specific active agent to treat a named disease;
A device reservoir or adhesive;
A particular permeation flux;
A specific skin site;
A defined release period; or
A commercial product by brand name.

When did U.S. Patent 4,863,970 lose exclusivity?

U.S. Patent 4,863,970 issued on September 5, 1989. For a U.S. patent based on an application filed before June 8, 1995, the general term was 17 years from grant, subject to applicable adjustment and terminal-disclaimer rules. On that basis, the ordinary expiration date was September 5, 2006. [1]

The patent is therefore expired. No current freedom-to-operate restriction arises from the expired patent itself.

A patent-term review should distinguish this patent from later continuation, divisional, improvement, or formulation patents. Expiration of the ’970 patent does not eliminate separate rights covering:

A specific active pharmaceutical ingredient;
A particular topical dosage form;
A branded formulation;
A patch architecture;
A manufacturing process;
A treatment method;
A particular salt, ester, polymorph, or prodrug; or
A later combination of oleic acid-related enhancers with a specified drug.

What is the Orange Book status of U.S. Patent 4,863,970?

The patent is not, by its claim structure, an Orange Book product patent. It is a broad platform formulation patent rather than a patent directed to a named FDA-approved drug product.

The FDA Orange Book lists patents submitted by sponsors for approved drug products, subject to FDA’s patent-listing framework. A general penetration-enhancer patent does not automatically appear in the Orange Book and does not create a Paragraph IV filing requirement by itself. [2]

The patent is not a biologic patent and does not create biosimilar exclusivity. A generic applicant would confront this patent only if a relevant listed drug patent or other enforceable patent separately covered the proposed product.

Were Paragraph IV challenges or patent litigation relevant?

A Paragraph IV certification is relevant to an ANDA applicant when the Orange Book lists an unexpired patent for the reference drug. U.S. Patent 4,863,970 is expired and is not, standing alone, a current Paragraph IV barrier. [3]

The claim structure also reduces the likelihood of a conventional Hatch-Waxman dispute because:

The patent does not identify one reference drug;
It covers a formulation platform across many possible active agents;
It does not appear to be an Orange Book-listed patent for a specific approved product; and
Its term expired in 2006.

Potential litigation involving a later product would more likely concern a later patent directed to the active drug, dosage form, delivery device, or method of use. The ’970 patent could have had historical relevance in formulation licensing or pre-expiration product development, but its expired status removes current injunctive leverage.

How strong is the patent estate for this technology?

The ’970 patent had meaningful historical breadth but limited current commercial strength.

Factor	Assessment
Chemical breadth	Broad within oleic-acid-related enhancers
Active-agent breadth	Very broad because no drug is specified
Dosage-form breadth	Broad for topical compositions, narrow outside composition claims
Device coverage	None apparent
Method-of-use coverage	None apparent in the supplied claims
Manufacturing coverage	None apparent
Exclusion sensitivity	High because diols and N-cyclic solvents are excluded
Claim clarity	Reduced by apparent dependency and terminology errors
Current enforceability	Expired
Current blocking value	None from the ’970 patent alone

The most important historical limitation was the exclusion of diols and N-cyclic solvents. Many transdermal systems use solvents such as propylene glycol, polyethylene glycol derivatives, pyrrolidones, or related co-solvents. A formulation outside the claimed chemical boundaries could avoid literal infringement even before expiration.

The broad active-agent language increased theoretical coverage, but it also made the patent vulnerable to prior-art attacks based on known topical vehicles, fatty acids, alcohols, and skin-penetration systems.

How does the patent compare with later transdermal patent strategies?

Later transdermal patent estates generally obtain stronger commercial leverage by combining the enhancer concept with product-specific limitations.

Patent strategy	Typical protection	Commercial effect
Platform composition	Fatty acid plus alcohol vehicle	Broad historical reach, limited product specificity
Drug-specific formulation	Named active plus defined enhancer ratios	Stronger linkage to a commercial product
Patch or delivery device	Reservoir, matrix, adhesive, or backing structure	Protects product architecture
Method of treatment	Specific drug, dose, indication, or patient group	Can support regulatory exclusivity strategy
Manufacturing process	Mixing, coating, drying, crystallization, or encapsulation	Creates production barriers
Release-profile claim	Flux, duration, or delivery-rate limitation	Targets clinically relevant performance

The ’970 patent is strongest as a foundational formulation patent and weakest as a modern product-defense estate because it lacks drug-specific, device-specific, and indication-specific claims.

What generic entry risks exist for products using these enhancers?

The expired patent creates no current generic-entry risk by itself. Risk analysis should focus on later, unexpired rights.

A generic or follow-on developer using oleic acid, oleyl alcohol, glycerol monooleate, glycerol dioleate, or glycerol trioleate should evaluate:

Active-ingredient patents;
Salt, ester, polymorph, or crystalline-form patents;
Topical formulation patents;
Patch and adhesive patents;
Method-of-use patents;
Manufacturing patents;
Regulatory exclusivity;
Orange Book listings; and
Patent settlement agreements affecting launch timing.

For a topical generic, formulation similarity alone does not establish infringement of the expired ’970 patent. The relevant question is whether a later patent claims the specific composition, dosage form, manufacturing process, or use.

What licensing or settlement implications remain?

The patent itself has no remaining patent-term licensing value because it is expired. Historical licenses may still matter for:

Royalty accounting;
Contractual know-how;
Confidential manufacturing information;
Improvements developed under a license; or
Separate unexpired patents in the same family or portfolio.

An expired patent does not terminate independent contractual obligations. It also does not place later improvements in the public domain if those improvements are separately patented.

What geographic coverage did the patent provide?

U.S. Patent 4,863,970 provided protection only in the United States. Foreign protection would have required separate national or regional patent rights.

A patent landscape for commercial diligence should therefore separate:

U.S. patent expiration;
European Patent Office family members;
Canadian, Australian, Japanese, and other national rights;
Patent Cooperation Treaty publications;
Continuations and divisionals; and
Later assignee or inventor filings covering related transdermal formulations.

The expiration of the U.S. patent does not establish expiration of any foreign counterpart.

Key Takeaways

U.S. Patent 4,863,970 covers topical pharmaceutical compositions using oleic acid, oleyl alcohol, glycerol esters of oleic acid, and lower alkanols.
Claim 1 is the broadest claim and covers a wide range of active pharmaceutical agents.
The vehicle expressly excludes diols and N-cyclic solvents.
Dependent claims narrow the alcohol concentration, active-agent loading, diluent content, and enhancer identity.
The supplied claim text contains apparent dependency and typographical defects in claims 11, 12, and 27.
The patent issued September 5, 1989, and its ordinary 17-year term expired September 5, 2006.
It is not, by its terms, an Orange Book patent directed to a named approved drug.
It creates no current Paragraph IV or biosimilar barrier.
Current commercial risk would arise from later patents covering specific drugs, formulations, devices, methods of use, or manufacturing processes.
The patent’s historical value was its broad platform coverage; its current enforceable value is zero because the patent has expired.

FAQs

Can a company use oleic acid and ethanol in a topical drug today?

Yes, expiration of U.S. Patent 4,863,970 removes that patent as a current U.S. restriction. Separate unexpired patents covering the active drug, formulation, device, treatment method, or manufacturing process must still be assessed.

Does polyethylene glycol avoid the patent’s diol exclusion?

Not automatically. The claim lists polyethylene glycol as an inert diluent but also excludes diols. The treatment of a particular polyethylene glycol material depends on claim construction, formulation role, molecular structure, and the patent’s specification.

Does the patent cover transdermal patches?

Not expressly. The supplied claims cover pharmaceutical compositions for topical application. They do not recite a patch, backing layer, adhesive, reservoir, membrane, or matrix.

Can an ANDA applicant file Paragraph IV against this patent?

The patent is expired, so it does not create a current Paragraph IV obstacle. Paragraph IV analysis would focus on unexpired Orange Book-listed patents for the relevant reference drug.

Does expiration of the U.S. patent expire foreign family patents?

No. U.S. expiration does not determine the term of foreign counterparts. Each foreign patent is governed by its national or regional filing, grant, adjustment, and maintenance history.

References

United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term: 35 U.S.C. § 154. https://www.uspto.gov/patents/laws/patent-term-adjustment
U.S. Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/approved-drug-products-therapeutic-equivalence-evaluations-orange-book
Legal Information Institute. (n.d.). 21 U.S.C. § 355(j): Abbreviated applications and patent certifications. Cornell Law School. https://www.law.cornell.edu/uscode/text/21/355
United States Patent and Trademark Office. (1989). U.S. Patent No. 4,863,970. Patent Center and patent records. https://patents.google.com/patent/US4863970A/en

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	77559	⤷ Start Trial
Germany	3779999	⤷ Start Trial
European Patent Office	0267617	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 4,863,970

Summary for Patent: 4,863,970