United States Patent 5,860,946: Scope, Claim Construction, Expiration, and Patent Landscape
U.S. Patent No. 5,860,946 protects a mechanical suppository applicator, not a pharmaceutical composition or active ingredient. Its independent claim requires a tube, a plunger with two circumferential flanges, an internal shoulder that engages between those flanges, and a slotted plunger tip divided into sectors. The dependent claims add an uneven number of sectors, radial stabilizing walls, disc-shaped guide walls, and resilient suppository-retention tongues.
The patent issued in 1999 and has no current blocking effect in the United States. Any commercial risk today would arise from later patents covering a particular applicator design, manufacturing method, packaging system, or drug-device combination, not from U.S. Patent 5,860,946 itself.
What does U.S. Patent 5,860,946 protect?
The patent protects the structure of a disposable or semi-disposable instrument for inserting a suppository. The claim set centers on controlled movement of a plunger inside a tube and on retaining the suppository before deployment.
The core elements are:
| Claim element |
Required structure |
Commercial function |
| Tube |
First end receives the suppository; second end receives the plunger |
Provides the delivery channel |
| Plunger |
First end has a circular cross section; second end projects from the tube |
Pushes the suppository through the tube |
| Two circumferential flanges |
Axially spaced on the plunger tip |
Control plunger retention and movement |
| Internal shoulder |
Extends inwardly from the tube’s first end and engages between the flanges |
Prevents unintended separation or excessive travel |
| Radial slots |
Divide the first end of the plunger into sectors |
Allow controlled deformation or release |
| Uneven sector count |
Added by claim 2 |
Narrows the sector geometry |
| Radial walls |
Extend between the plunger tip and press button and abut the tube wall |
Stabilize the plunger |
| Disc-shaped walls |
Axially spaced and sized to the tube’s inner diameter |
Guide the plunger |
| Resilient tongues |
Opposed tongues retain the suppository through mating recesses |
Hold the suppository in position |
The patent is therefore a combination patent. A product must contain the claimed combination to infringe claim 1. A product that uses only a tube and plunger, without the claimed flange-and-shoulder arrangement and slotted sector construction, would not satisfy the full language of claim 1.
How should independent claim 1 be construed?
Claim 1 is the principal infringement claim. It requires all of the following limitations:
- An instrument for inserting a suppository.
- A tube.
- A first tube end adapted to receive the suppository.
- A second tube end through which a plunger is inserted.
- A plunger with a first end having a circular cross section.
- Two axially spaced circumferential flanges on the plunger’s first end.
- A second plunger end projecting from the tube’s second end.
- An inwardly extending shoulder at the tube’s first end.
- The shoulder engaging between the two flanges.
- A plunger first end divided by radial slots into multiple sectors.
The last limitation is important. A solid plunger tip, a tip with longitudinal grooves that do not form separate sectors, or a tip divided by non-radial structures would present a substantial non-infringement position, subject to the ordinary meaning of the claim and any prosecution-history limitations.
The claim does not expressly require:
- A particular active pharmaceutical ingredient.
- A specific suppository formulation.
- A particular tube material.
- A specific number of sectors.
- A particular insertion depth.
- A particular external applicator shape.
- A particular route other than suppository delivery.
- A particular manufacturing process.
Those omissions limit the claim’s reach to mechanical architecture rather than pharmaceutical content.
What do claims 2 through 5 add?
What does claim 2 protect?
Claim 2 requires that the plunger tip be divided into an uneven number of sectors. A three-sector or five-sector tip could fall within this claim if all claim 1 limitations are also present.
Claim 2 does not independently protect an unevenly divided plunger. It depends on claim 1 and inherits every limitation of that claim.
What does claim 3 protect?
Claim 3 adds angularly spaced radial walls between the plunger’s first end and its press button. These walls must abut the inner wall of the tube.
The likely purpose is to reduce lateral movement, maintain alignment, and improve force transmission during actuation. A plunger that merely has narrow guide ribs may avoid the claim if those ribs do not satisfy the claimed radial-wall configuration or do not abut the tube wall.
What does claim 4 protect?
Claim 4 depends on claim 3 and adds axially spaced disc-shaped walls. Each disc has a diameter corresponding to the tube’s inner diameter.
This claim targets a more specific guide structure than claim 3. It creates a layered plunger-support arrangement consisting of radial walls and disc-shaped guide walls.
What does claim 5 protect?
Claim 5 adds opposed resilient tongues that hold the suppository. The inward-facing walls of the tongues must have recesses that mate with the outer contour of the suppository.
This limitation is directed to retention before use. A device that retains a suppository through friction, adhesive, a closed membrane, or a cylindrical interference fit may fall outside claim 5 if it lacks the claimed opposing tongues and contour-matching recesses.
Is U.S. Patent 5,860,946 a drug patent?
No. It is a medical-device patent.
The patent does not claim:
- An active ingredient.
- A suppository composition.
- A dosage strength.
- A therapeutic indication.
- A release-rate profile.
- A pharmaceutical manufacturing process.
- A drug-device combination defined by a particular medicine.
The word “suppository” describes the article delivered by the instrument. It does not convert the claims into pharmaceutical claims.
What is the Orange Book status of U.S. Patent 5,860,946?
U.S. Patent 5,860,946 is not an Orange Book-listed drug patent.
The FDA Orange Book identifies patents submitted for approved drug products, including patents covering active ingredients, drug products, formulations, and methods of use. A standalone applicator patent generally does not qualify for Orange Book listing unless it falls within the statutory categories applicable to the approved drug product and is properly submitted by the new drug application holder (FDA, 2024).
Consequences include:
| Issue |
Status |
| Orange Book-listed patent |
No |
| Paragraph IV certification |
Not applicable to this patent as a standalone device patent |
| FDA drug exclusivity |
None created by this patent |
| FDA device clearance or approval |
Not established by the patent itself |
| Hatch-Waxman litigation |
Not triggered solely by this patent |
| Biosimilar litigation |
Not applicable |
A drug sold with an applicator could have separate Orange Book-listed formulation or method-of-use patents. Those rights would need to be analyzed independently.
When did U.S. Patent 5,860,946 lose exclusivity?
The patent issued on January 19, 1999. Its enforceable term ended no later than January 19, 2019 under the modern patent-term framework, and the patent is expired as of 2026 (U.S. Patent No. 5,860,946, 1999; 35 U.S.C. § 154).
The precise terminal date depends on the application’s effective filing and priority dates, and on any patent-term adjustment or terminal disclaimer. Those factors do not change the current commercial conclusion: the patent has no live U.S. exclusionary term.
| Milestone |
Date or status |
| Patent issue |
January 19, 1999 |
| Patent type |
Utility patent |
| Subject matter |
Suppository insertion instrument |
| Current U.S. enforceability |
Expired |
| Current Paragraph IV relevance |
None |
| Current biosimilar relevance |
None |
What patent landscape surrounds suppository applicators?
The relevant landscape is a device patent landscape, not a conventional drug patent landscape. Later patent activity can be divided into five technical groups.
Applicator geometry
These patents may cover:
- Telescoping tubes.
- Expandable or collapsible applicators.
- Breakaway tips.
- Rounded or tapered insertion ends.
- Single-use molded applicators.
- Multi-dose applicator bodies.
A later product can avoid the 5,860,946 architecture by using a plunger that does not have two circumferential flanges engaging an internal shoulder.
Suppository retention
Later patents may claim:
- Flexible fingers.
- Frangible retaining bridges.
- A dissolvable retaining membrane.
- Vacuum or friction retention.
- A removable cap.
- A cavity molded to the suppository shape.
Claim 5 is narrower than claim 1 because it requires opposed resilient tongues with contour-matching recesses.
Plunger guidance and actuation
Potentially relevant later claims may cover:
- Ribbed plungers.
- Ratcheting plungers.
- Locking plungers.
- Dose-control stops.
- One-handed actuation.
- Plungers with collapsible segments.
- Ergonomic press buttons.
Claims 3 and 4 show the type of guidance architecture that the patent sought to protect, but they do not prevent all guide-rib or disc arrangements after expiration.
Drug-device combinations
A pharmaceutical company may hold separate rights covering:
- A suppository composition.
- A particular excipient system.
- Controlled or sustained release.
- Temperature-sensitive formulations.
- A prefilled applicator.
- A packaged combination of drug and applicator.
- A method of treating a named condition using the suppository.
These rights are distinct from the expired applicator patent.
Manufacturing and packaging
Patent barriers may also concern:
- Automated suppository loading.
- In-line applicator assembly.
- Sterile or low-bioburden packaging.
- Heat-sealing and tamper evidence.
- Cold-chain handling.
- Molded polymer components.
- Inspection systems for suppository placement.
Manufacturing patents can remain commercially relevant even when the original applicator patent has expired.
How strong was the patent estate?
The estate represented by U.S. Patent 5,860,946 is narrow in claim count but technically coherent. Claim 1 combines the tube, flange, shoulder, and slotted-sector features. Claims 2 through 5 provide progressively narrower fallback positions.
Its historical strengths were:
- A concrete mechanical combination.
- Multiple cooperating retention and guidance elements.
- Dependent claims directed to commercially practical structures.
- Coverage of both plunger movement and suppository retention.
Its limitations were:
- No composition claims.
- No method-of-treatment claims.
- No manufacturing claims.
- No express coverage of broad applicator categories.
- Dependence on specific flange, shoulder, slot, tongue, and guide-wall structures.
- Expiration of the U.S. term.
As a current asset, the patent has no enforcement value. Its technical disclosure may still be relevant for prior-art analysis against later applicator claims.
Which companies are challenging U.S. Patent 5,860,946?
No Paragraph IV challenger is relevant because the patent is not an Orange Book-listed drug patent and is expired. No biosimilar applicant would be required to address it under the Biologics Price Competition and Innovation Act.
A competitor could have challenged validity during the patent’s active term through litigation, reexamination, or other USPTO proceedings. The supplied claim text does not establish a litigation history, settlement agreement, license, assignment chain, or post-grant proceeding. Those matters are separate from claim scope and cannot be inferred from the claims.
What generic launch risks exist today?
The patent creates no current generic-launch barrier. A pharmaceutical company can sell a suppository applicator that practices the expired claim set without infringing this patent.
Current launch risks may instead involve:
- Active patents on the suppository formulation.
- Active patents on a prefilled applicator.
- Later patents on retention mechanisms.
- Design patents covering the product appearance.
- FDA requirements for the drug, device, or combination product.
- Trademark and trade-dress rights.
- Manufacturing patents owned by component suppliers.
- Contractual restrictions in licensing or supply agreements.
The absence of live rights under 5,860,946 does not establish freedom to operate across the entire product configuration.
How does this patent compare with formulation and method-of-use patents?
| Patent category |
Subject matter |
Orange Book relevance |
Current relevance of 5,860,946 |
| Composition patent |
Active ingredient or formulation |
Often relevant |
None |
| Formulation patent |
Release, excipients, stability |
Potentially relevant |
None |
| Method-of-use patent |
Treatment indication or dosing |
Potentially relevant |
None |
| Device patent |
Applicator structure |
Usually not listed |
Expired |
| Manufacturing patent |
Assembly or production method |
Usually not listed |
Not covered |
| Packaging patent |
Container, seal, or presentation |
Usually not listed |
Not covered |
Key Takeaways
- U.S. Patent 5,860,946 is a mechanical suppository-applicator patent, not a drug patent.
- Claim 1 requires a tube, a plunger, two circumferential plunger flanges, an internal tube shoulder, and a slotted plunger tip divided into sectors.
- Claim 2 requires an uneven number of sectors.
- Claims 3 and 4 cover specific radial-wall and disc-wall guidance structures.
- Claim 5 covers opposed resilient suppository-retention tongues with contour-matching recesses.
- The patent does not claim a drug, formulation, dosage, indication, or manufacturing process.
- It is not an Orange Book-listed patent and has no Paragraph IV or biosimilar role.
- The U.S. patent term has expired, eliminating current infringement risk from this patent.
- Later applicator, formulation, combination-product, packaging, and manufacturing patents remain the relevant freedom-to-operate issues.
- The patent’s main residual value is prior-art significance for later device claims.
FAQs
Can an applicator infringe claim 1 without containing an active drug?
Yes. Claim 1 is directed to the instrument. The product does not need to contain a particular active ingredient if it satisfies all structural limitations.
Does claim 5 cover every applicator that holds a suppository with flexible fingers?
No. Claim 5 requires opposed resilient tongues and recesses in their facing walls that mate with the suppository’s outer contour, in addition to all limitations inherited from claims 1 and 3.
Can a three-sector plunger fall within claim 2?
Yes. A three-sector plunger may satisfy the uneven-sector limitation, but it must also satisfy every limitation of claim 1.
Does expiration of this patent eliminate FDA requirements for a suppository applicator?
No. Patent expiration removes the patent exclusion right. It does not remove applicable FDA requirements for the drug, device, packaging, labeling, quality systems, or combination product.
Can the patent still be cited against a later patent application?
Yes. An expired patent can remain relevant as prior art in assessing novelty, obviousness, written description, or claim scope, even though it cannot be enforced against current products.
References
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Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.
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U.S. Patent No. 5,860,946. (1999). Instrument for inserting a suppository. United States Patent and Trademark Office.
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35 U.S.C. § 154. Patent term.
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21 U.S.C. § 355. New drug applications and patent information.
