Executive summary. U.S. Patent No. 5,538,353 protects a single-use liquid applicator that combines a fracturable vial, a molded receiving pocket, pivotable gripping wings, localized fracturing tabs, and a porous applicator surface. Claims 1 and 8 are the principal independent claims. The patent is directed to device architecture, not to a pharmaceutical active ingredient, formulation, treatment method, or manufacturing process. Its 20-year patent term has expired, so the claims no longer create an enforceable U.S. exclusion right. The patent would not ordinarily generate Orange Book, Paragraph IV, or biosimilar issues.

U.S. Patent 5,538,353 Liquid Applicator: Claim Scope, Expiration, and Patent Landscape

What invention does U.S. Patent 5,538,353 protect?

The patent protects a mechanically actuated ampoule applicator. Its core operating sequence is:

A liquid is sealed inside a vial made of fracturable material.
The vial is placed inside a pocket in a body.
A porous element closes the pocket's open side.
The user squeezes or pivots one or more gripping members.
Tabs or equivalent structures flex the pocket inward.
The vial fractures inside the applicator.
The liquid passes through the porous element for topical or local application.

The inventive focus is the transfer and localization of squeezing force. The claims do not require a particular liquid, active pharmaceutical ingredient, therapeutic indication, vial glass composition, absorbent material, or sterilization process.

The patent's principal technical concepts are:

Technical element	Claim significance
Fracturable vial	Must contain the liquid and break under force
Pocket	Receives and supports the vial
Open side	Is closed by the porous applicator element
Flange	Supports the gripping members
Pivotable gripping members	Receive manual squeezing force
Fracturing structure or tabs	Redirect force into the pocket and vial
Retaining tab	Forces the vial away from the open side in specified embodiments
Breaking tab or tabs	Applies force generally at the pocket axis
Porous element	Allows liquid to flow out after fracture
Rib and textured surface	Provides handling and gripping assistance in dependent claims

What are the independent claims in Patent 5,538,353?

Claim 1: two-wing elongated applicator

Claim 1 requires an elongated construction with a pair of elongated, wing-like gripping members. The vial and pocket must have generally collinear longitudinal axes. The pocket has an axial plane that includes its axis and is substantially parallel to the pocket's open side.

The claim requires:

an elongated closed fracturable vial;
an elongated pocket shaped to receive the vial;
a flange along the pocket's open side;
two wing-like gripping members;
pivotable support of the gripping members by the flange;
fracturing structure between the pocket and gripping members;
inward flexing of the pocket when the members move toward one another; and
a porous element closing the open side.

Claim 1 is structurally narrow because it requires the relationship among the elongated vial, elongated pocket, flange, two wings, and inward-flexing fracture mechanism. A product using a nonpivoting actuator, a separate external crushing tool, or a vial not housed in the claimed pocket would have a substantial noninfringement position.

Claim 8: force-localization applicator

Claim 8 is independently drafted around force localization. It requires:

a closed fracturable vial;
a pocket;
a flange;
at least one wing-like gripping member;
a gripping area;
a smaller fracturing area;
a mechanism that transfers squeezing force from the gripping area to the vial; and
a porous element.

Claim 8 does not expressly require the elongated vial, elongated pocket, pair of wings, retaining tab, or breaking tab required by several narrower claims. Its central limitation is that the fracturing area is smaller than the gripping area, thereby concentrating force.

Claim 8 may cover a broader range of applicator geometries than claim 1. It still requires the force-transfer architecture and a porous outlet. A product that breaks the vial by direct end compression, without the claimed localized fracturing area, would fall outside the literal scope of claim 8.

How do claims 1 through 20 divide the protected subject matter?

Claims 2 through 7 depend from claim 1. Claims 9 through 20 depend from claim 8.

Claims	Subject matter	Limiting features
1	Core elongated applicator	Two wings, elongated vial and pocket, inward flexing
2	Handling structure	Longitudinal ribs and textured surfaces
3-4	Retaining and breaking tabs	One off-axis retaining tab and one axial breaking tab
5-7	Multiple-tab structure	One retaining tab and two spaced breaking tabs
8	Core force-localization applicator	Fracturing area smaller than gripping area
9	Multiple tabs	Plurality of tabs spaced along the pocket
10	Elongated geometry	Elongated vial and pocket, collinear axes
11-12	Dual-wing handling construction	One or more tabs per wing, shorter tabs, ribs, texture
13-16	Retaining/breaking tab pair	Off-axis retaining tab and axial breaking tab
17-20	Three-tab arrangement	One retaining tab and two spaced breaking tabs

The dependent claims create fallback positions around tab placement, tab orientation, pocket geometry, and ergonomic handling. They are narrower than their respective independent claims but may be more difficult to read on generic applicators unless the accused product reproduces the specific tab arrangement.

What is the scope of the retaining-tab and breaking-tab limitations?

The retaining-tab and breaking-tab architecture is the most technically specific portion of the patent.

The retaining tab must move the pocket inward at a location between the axial plane and the flange. The claimed result is that the vial is forced away from the open side of the pocket.

The breaking tab acts generally at the pocket's axial plane. In claims 4 and 16, the engagement surfaces are positioned differently:

the retaining-tab surface intersects the pocket between the axial plane and flange; and
the breaking-tab surface intersects the pocket at a location aligned with the axial plane.

Claims 5 through 7 and 17 through 20 add two breaking tabs. These tabs are spaced from one another and from the retaining tab along the pocket. Claim 7 and claim 20 also require oblique tab structures extending between the gripping member, flange, and pocket.

These limitations are important in infringement analysis. A product with generic ribs, crush points, or internal supports may not satisfy the claims unless those structures perform the claimed spatial and mechanical functions. Claim construction would likely focus on:

the meaning of "axial plane";
the location of tab engagement with the pocket;
whether a structure is a "gripping member";
whether the pocket actually flexes inward;
whether the vial is forced away from the open side; and
whether the fracture area is smaller than the gripping area.

What formulations and products are protected by Patent 5,538,353?

No formulation is protected by the asserted claim language.

The claims cover an applicator device capable of containing and dispensing a liquid. They do not recite:

an active pharmaceutical ingredient;
a concentration;
a solvent or excipient;
pH;
viscosity;
a preservative;
a therapeutic indication;
a dosage;
a patient population; or
a method of treatment.

The liquid could potentially be a pharmaceutical, antiseptic, cosmetic, diagnostic reagent, or other topical composition, assuming the applicator otherwise satisfies the device limitations. The patent therefore has product-platform relevance rather than drug-specific exclusivity.

A party commercializing the same applicator with a different liquid would not avoid the device claims merely by changing the contents. Conversely, a party using the same liquid in a materially different dispenser would not necessarily implicate the patent.

When did U.S. Patent 5,538,353 lose exclusivity?

The patent's enforceable term expired no later than the ordinary 20-year term measured from its earliest effective nonprovisional filing date, subject to any applicable patent-term adjustment or terminal disclaimer. U.S. Patent No. 5,538,353 issued in 1996, and its ordinary term therefore ended roughly in the 2014-2016 period rather than continuing through the present.

The patent is now expired and cannot support a new U.S. infringement action for current commercial activity. Patent expiration does not erase historical infringement exposure during the enforceable term, but it eliminates prospective exclusivity.

The patent's expiration also means that:

a current applicator manufacturer does not need a license to practice the expired claims in the United States;
freedom-to-operate analysis must shift to later patents and unrelated family members;
any continuation, divisional, or improvement patent must be reviewed separately; and
the expired patent remains relevant as prior art and as a technical disclosure.

The patent record should be used to confirm the precise expiration calculation, including any term adjustment or disclaimer. The governing statutory framework is 35 U.S.C. § 154, and USPTO patent-term rules apply to the final calculation [1, 2].

What is the Orange Book status of Patent 5,538,353?

Patent 5,538,353 is not the type of patent ordinarily listed in the FDA Orange Book.

The Orange Book identifies patents submitted for approved drug products, including patents claiming the drug substance, drug product, or approved method of use. This patent claims a liquid applicator device. Its claims do not identify a drug product or therapeutic use [3].

The expected regulatory position is:

Regulatory issue	Relevance
Orange Book listing	Not ordinarily applicable
Hatch-Waxman Paragraph IV	Not ordinarily applicable
Abbreviated New Drug Application	Relevant only to a drug product, not this device patent
Biosimilar application	Not applicable
FDA device classification	Potentially relevant depending on intended use and product configuration
Combination product status	Potentially relevant if the applicator is marketed with a drug

If the applicator is sold prefilled with a drug, FDA could evaluate the overall product as a drug-device combination product. That regulatory classification would not revive the expired patent or convert its device claims into drug claims.

Are Paragraph IV challenges or biosimilar disputes associated with this patent?

No conventional Paragraph IV or biosimilar dispute follows from the claims provided.

Paragraph IV certifications concern patents listed for a reference listed drug in the Orange Book. Biosimilar litigation concerns patents relevant to a licensed biologic under the Biologics Price Competition and Innovation Act. Patent 5,538,353 claims a mechanical applicator rather than a small-molecule drug or biologic [3, 4].

A generic drug company could still face a separate device patent issue if it markets a prefilled applicator or combination product covered by an unexpired device patent. That analysis would involve the later patent estate, not the expired claims of Patent 5,538,353.

How strong was the patent estate during its enforceable term?

The patent had meaningful protection against close copies of the claimed mechanical arrangement, but its strength was narrower than a broad platform patent.

Strengths

Two independent claims address different mechanical formulations.
Claim 1 covers a detailed elongated dual-wing design.
Claim 8 focuses on force concentration and may reach alternative geometries.
Dependent claims address specific tab arrangements and ergonomic structures.
The claims combine structural and functional limitations, which can make literal design copying easier to identify.

Weaknesses

The claims are limited to an applicator containing a fracturable vial.
The claims require a porous element over the pocket opening.
The claims depend heavily on spatial relationships and force-transfer behavior.
The patent does not cover the liquid formulation or therapeutic use.
Alternative fracture mechanisms can avoid the tab architecture.
Expiration removes current enforcement leverage.

The strongest historical infringement case would likely involve a device closely reproducing the two-wing pocket, tab locations, inward flexing, and porous closure. A broad challenge based on a different ampoule-breaker design would have a stronger noninfringement argument than a challenge involving only cosmetic changes.

What design-arounds avoid the claimed architecture?

Potential design-around paths include:

Use a nonfracturable flexible container, such as a squeezable pouch.
Break the vial before insertion into the applicator.
Use a separate cap, plunger, blade, or crushing element rather than pivotable wings.
Place the fracture mechanism at the vial end instead of along the pocket.
Eliminate the porous element and dispense through a nozzle or aperture.
Use a single molded actuator that does not pivot relative to a flange.
Use a pocket that does not flex inward to transfer force.
Use a vial and pocket with non-collinear axes.
Use a distributed compression mechanism without the claimed localized fracturing area.
Separate the vial from the applicator until immediately before use.

These approaches require analysis against all limitations, including the doctrine of equivalents. Because the patent is expired, design-around work is primarily relevant to later patents, product differentiation, and historical litigation analysis.

Which companies are challenging Patent 5,538,353?

The patent is expired, and no current Paragraph IV or biosimilar challenge is expected. The provided record does not establish a material current litigation campaign involving the patent.

The likely competitive field is not defined by drug manufacturers. It consists of companies producing:

single-use ampoule applicators;
antiseptic swab applicators;
topical medication dispensers;
cosmetic ampoule packages;
diagnostic liquid dispensers; and
prefilled drug-device combination products.

A complete company-by-company landscape would require review of later patents citing or improving the applicator design. The expired patent itself does not prevent current competition.

What patent litigation and settlement issues matter?

For any historical dispute, the relevant questions would have been:

whether the accused device contained a fracturable vial;
whether the vial was received in the claimed pocket;
whether the gripping member pivoted relative to the flange;
whether the pocket flexed inward;
whether the tab geometry matched the asserted claim;
whether the porous element closed the open side; and
whether the accused product was sold during the enforceable term.

Settlement value would have declined sharply after expiration because injunctive relief was no longer available for future sales. Any remaining value would have related to past damages, release scope, supply contracts, confidential know-how, or later patents.

How does Patent 5,538,353 compare with drug and biologic patent estates?

Estate type	Typical protected subject matter	Applicability here
Small-molecule drug patent	Active ingredient, salt, polymorph, formulation, method of use	No direct claim
Biologic patent	Antibody sequence, production, formulation, treatment	No direct claim
Device patent	Structure, operation, packaging, delivery mechanism	Directly applicable
Combination-product patent	Drug-device integration or delivery system	Potentially adjacent
Manufacturing patent	Process, assembly, sterilization, filling	Not claimed
Method-of-use patent	Therapeutic administration	Not claimed

Patent 5,538,353 should therefore be screened in a device freedom-to-operate review, not treated as a conventional drug-exclusivity asset.

What is the commercial and revenue exposure?

The patent does not protect a named drug, so revenue exposure cannot be measured from drug sales or Orange Book market share. During its term, exposure would have depended on sales of applicators using the claimed vial-pocket-wing architecture.

Current commercial exposure from this patent is zero as a forward-looking exclusion right because the patent has expired. Revenue risk may still exist from later patents covering:

prefilled applicator assemblies;
vial-breaking mechanisms;
porous applicator heads;
sterile packaging;
drug-device combination products;
automated filling and assembly; and
specific therapeutic liquids.

The commercial value of the expired patent is therefore historical and technical, not an active royalty or market-blocking asset.

Key takeaways

Patent 5,538,353 is a device patent for a fracturable-vial liquid applicator.
Claims 1 and 8 are the two principal independent claims.
Claim 1 centers on an elongated dual-wing applicator with a collinear vial and pocket.
Claim 8 centers on a gripping area that is larger than a localized fracturing area.
Claims 3-7 and 13-20 narrow the invention through retaining-tab and breaking-tab geometry.
No claim covers a drug substance, formulation, therapeutic indication, or manufacturing process.
The patent's U.S. term expired approximately in the 2014-2016 period under the ordinary 20-year framework.
It is not ordinarily an Orange Book patent and does not create a Paragraph IV or biosimilar pathway issue.
Current freedom-to-operate risk depends on later patents, not the expired claims.
The most credible historical design-arounds replace the pivoting wing, tab-based fracture mechanism, porous closure, or fracturable vial.

FAQs about U.S. Patent 5,538,353

Can a company manufacture the claimed applicator today?

Yes, the patent's U.S. term has expired. Later patents covering improvements, combination products, or manufacturing processes must still be reviewed.

Does Patent 5,538,353 protect an ampoule drug?

No. It protects the applicator structure. The liquid inside the vial is not limited to a specified drug or formulation.

Does the patent cover a squeeze bottle?

Generally, not on the claims provided. A squeeze bottle would need to satisfy the fracturable-vial, pocket, force-transfer, and porous-element limitations.

Could the patent be listed in the Orange Book?

Not ordinarily. The claims are directed to a liquid applicator rather than a drug substance, drug product, or approved method of use.

Is a license required to sell a similar product in the United States?

Not under the expired patent. A license could still be required under later patents or contractual rights unrelated to Patent 5,538,353.

References

United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term provisions under 35 U.S.C. § 154. https://www.uspto.gov/patents/laws
United States Patent and Trademark Office. (1996). U.S. Patent No. 5,538,353, Liquid applicator. https://patents.google.com/patent/US5538353
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book
U.S. Food and Drug Administration. (2024). Biosimilar and interchangeable biosimilar products. https://www.fda.gov/drugs/therapeutic-biologics-applications-bla/biosimilars fda

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	202686	⤷ Start Trial
Australia	4249296	⤷ Start Trial
Australia	695218	⤷ Start Trial
Canada	2228942	⤷ Start Trial
Germany	69521631	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,538,353

Summary for Patent: 5,538,353