US Patent 5,776,435: Scope, Claim Construction, Expiration, and Triclosan Toothpaste Patent Landscape

US Patent 5,776,435 covers dentifrice compositions combining 0.25% to 0.35% of a substantially water-insoluble, noncationic antibacterial agent, especially triclosan, with a siliceous abrasive and a delivery-and-retention enhancing agent. The principal enhancement technology is an anionic maleic acid or maleic anhydride copolymer, particularly a methyl vinyl ether/maleic anhydride copolymer commonly known as PVM/MA or Gantrez-type polymer.

The patent is no longer enforceable in the United States. Its effective patent term ended approximately 20 years after the earliest relevant nonprovisional filing date, subject to any patent-term adjustment or extension recorded in the official patent file. The commercial significance of the patent therefore lies in its historical protection of triclosan dentifrice technology, not in current exclusionary rights.

What technology does US Patent 5,776,435 protect?

The patent protects a delivery system for depositing an antibacterial agent on tooth and gum surfaces. Its central technical proposition is that a water-soluble or water-swellable enhancing agent can improve both:

Delivery of the antibacterial agent from the dentifrice to oral surfaces; and
Retention of the antibacterial agent after rinsing, salivary exposure, or normal oral activity.

The claimed composition generally requires the following elements:

Claim element	Claimed range or requirement
Dosage form	Oral composition dentifrice
Vehicle	Orally acceptable aqueous humectant vehicle
Abrasive	5% to 30% siliceous polishing agent
Antibacterial agent	0.25% to 0.35% substantially water-insoluble, noncationic agent
Enhancing agent	0.05% to 4%
Surfactant or flavor	At least one is required in most independent claims
Anticalculus limitation	No polyphosphate anticalculus agent in an effective anticalculus amount
Vehicle exclusion	Vehicle cannot be polyethylene glycol if it reduces antibacterial activity
Optional active	Fluoride source under claim 19

The claims are directed to compositions, not to a method of brushing, a method of treating gingivitis, a manufacturing process, or a particular commercial toothpaste brand.

Which claims are independent, and what does each claim require?

Claims 1, 2, 8, and 18 are the principal composition claims. Claims 3 through 7, 9 through 17, and 19 add narrower limitations.

Claim 1: Broad functional enhancer formulation

Claim 1 requires:

A dentifrice;
An aqueous humectant vehicle;
5% to 30% siliceous polishing agent;
0.25% to 0.35% substantially water-insoluble, noncationic antibacterial agent;
A surface-active agent or flavoring oil;
0.05% to 4% of a water-soluble or water-swellable antibacterial-enhancing agent;
Enhancer molecular weight of approximately 100 to 1,000,000;
At least one carboxylic delivery-enhancing group;
At least one organic retention-enhancing group;
No effective polyphosphate anticalculus amount; and
No polyethylene glycol vehicle that reduces antibacterial activity.

Claim 1 is chemically broad because it does not limit the antibacterial agent to triclosan or the enhancer to a particular polymer. It can reach a broad class of anionic or amphiphilic delivery systems if the functional limitations are satisfied.

Claim 2: Maleic acid or maleic anhydride copolymer

Claim 2 narrows the enhancing agent to an anionic copolymer of maleic acid or maleic anhydride with another ethylenically unsaturated polymerizable monomer.

This is the commercially important polymer limitation. The claim is directed to the class of PVM/MA-type copolymers, but the literal scope is not limited to methyl vinyl ether unless claims 4 through 6 are also implicated.

Claim 8: Functional enhancer plus phenolic antibacterial

Claim 8 requires a substantially water-insoluble, noncationic phenolic antibacterial agent and a delivery-and-retention enhancing agent. Unlike claim 2, it does not expressly require a maleic acid or maleic anhydride copolymer.

Claim 8 can therefore cover an enhancer selected by function and chemical structure, subject to the claim's concentration and composition limitations.

Claim 18: Triclosan and PVM/MA composition

Claim 18 is the most commercially specific independent claim. It requires:

5% to 30% siliceous polishing agent;
0.25% to 0.35% triclosan;
A surface-active agent or flavoring oil; and
0.05% to 4% copolymer of maleic acid or maleic anhydride with methyl vinyl ether.

Unlike claim 1, claim 18 does not separately recite the functional phrases requiring the copolymer to enhance delivery and attachment. It is therefore potentially easier to apply to a conventional triclosan/PVM/MA dentifrice, provided all remaining limitations are met.

What antibacterial agents fall within the patent claims?

Claim 3 identifies several antibacterial classes:

Halogenated diphenyl ethers;
Halogenated salicylanilides;
Benzoic esters;
Halogenated carbonilides; and
Phenolic compounds.

Claim 7 expressly identifies triclosan. Claim 8 and claim 9 cover phenolic compounds, including:

Phenol;
Thymol;
Eugenol; and
2,2'-methylene bis(4-chloro-6-bromophenol).

Triclosan is the key commercial active. The specified 0.25% to 0.35% range is particularly significant because traditional triclosan dentifrice formulations commonly used approximately 0.3% triclosan.

The “substantially water insoluble” and “noncationic” requirements exclude many water-soluble cationic antiseptics, including conventional quaternary ammonium actives that operate through a different delivery and substantivity mechanism.

What formulations are protected by the PVM/MA claims?

Claims 2, 4, 5, 6, and 18 define the principal PVM/MA formulation subestate.

Claim	Additional limitation
2	Maleic acid or maleic anhydride copolymer with another ethylenically unsaturated monomer
4	Other monomer is methyl vinyl ether; molar ratio of 4:1 to 1:4
5	Copolymer molecular weight of 30,000 to 1,000,000
6	Average molecular weight of approximately 70,000
18	Triclosan plus maleic acid or maleic anhydride/methyl vinyl ether copolymer

The claims do not require a particular commercial PVM/MA supplier, trade name, polymer salt, particle size, viscosity, or degree of neutralization. A formulation can potentially fall within the claims even if the polymer is supplied under a different trade designation, provided the composition satisfies the structural and concentration limitations.

The concentration range is broad. At 0.05% to 4%, the claims cover low-level substantivity enhancers through materially higher polymer concentrations that may affect viscosity, flavor release, foaming, and processing.

How broad are the functional limitations in claims 1 and 8?

The functional terms “delivery-enhancing” and “retention-enhancing” are central to claim scope and potential claim construction disputes.

Claim 14 provides structural guidance. It identifies acidic delivery-enhancing groups such as:

Carboxylic acids;
Phosphoric acids;
Phosphinic acids;
Sulfonic acids;
Corresponding salts and mixtures.

The retention-enhancing group is defined through the formula:

“--(X)n--R”

where:

X can be O, N, S, SO, SO2, P, PO, or Si;
R can be hydrophobic alkyl, aryl, alkaryl, alkenyl, acyl, aralkyl, heterocyclic, or inert-substituted derivatives; and
n can be zero or any positive integer.

Claims 15 through 17 further narrow the enhancer to an anionic polymer with repeated delivery- and retention-enhancing groups. The relevant groups may be bonded to the same atom, vicinal atoms, or other atoms in the polymer chain.

A party analyzing infringement would need to address both composition and function. Merely identifying an acidic polymer is insufficient. The accused formulation must satisfy the claim's delivery and retention relationship, either literally or under an applicable equivalent theory. Conversely, a formulation using PVM/MA may present a stronger literal-read risk under claim 18 because that claim identifies triclosan and the copolymer directly.

What are the principal design-around positions?

A formulation seeking to avoid the literal scope could change one or more of the following elements:

Design-around variable	Potential effect
Triclosan concentration	A concentration below 0.25% or above 0.35% may avoid the stated range, subject to range interpretation and equivalents
Antibacterial active	Use a cationic, ionic, water-soluble, or nonphenolic active
Polymer	Use a non-maleic copolymer or a polymer without the claimed functional group combination
Polymer concentration	Use less than 0.05% or more than 4%
Abrasive	Replace or materially reduce the siliceous polishing agent
Vehicle	Use polyethylene glycol only if it does not trigger the stated activity-reduction exclusion
Anticalculus system	Introduce an effective polyphosphate anticalculus amount, which would conflict with the express claim limitation
Dosage form	Use a mouthrinse, gel, varnish, lozenge, or other non-dentifrice format

The concentration design-arounds are not automatically safe. A formulation outside a claimed numerical range may still raise an equivalents issue depending on the technical effect, prosecution history, and the degree of deviation. The strongest design-around positions generally change the active, polymer chemistry, or dosage form rather than relying solely on a small concentration shift.

When did US Patent 5,776,435 lose exclusivity?

The patent issued on July 7, 1998. Its enforceable term was governed principally by the 20-year term measured from the earliest effective US nonprovisional filing date under the Uruguay Round Agreements Act framework, rather than by 17 years from issuance. The patent therefore expired approximately in the 2014-2015 period, depending on the recorded priority and any term adjustment.

Milestone	Date or period
US patent issuance	July 7, 1998
Statutory term basis	20 years from applicable earliest nonprovisional filing
Expected ordinary expiration	Approximately 2014-2015
Current status	Expired; no current US exclusionary right

The controlling expiration date is the date shown in the USPTO patent record after accounting for priority, patent-term adjustment, terminal disclaimers, and any patent-term extension. The patent's issuance date does not determine the expiration date.

Because the patent has expired, a current generic or branded competitor does not need a Paragraph IV challenge to clear this patent. A Paragraph IV certification is relevant to an unexpired listed patent. An expired patent generally does not create a present statutory stay or launch-blocking right.

What is the Orange Book status of the patent and related triclosan products?

The relevant regulatory product history is associated with triclosan-containing dentifrice products, including Colgate Total. The FDA approved Colgate Total as a prescription drug product in the 1990s under an NDA pathway covering a toothpaste containing triclosan and sodium fluoride. The product's regulatory history is distinct from the patent's private exclusionary rights.

Issue	Assessment
FDA product status	Triclosan dentifrice historically received FDA approval
Active ingredients	Triclosan and fluoride in the original product configuration
Patent listing relevance	Depends on the specific NDA, patent declaration, and Orange Book listing history
Current patent enforceability	US Patent 5,776,435 is expired
Current Paragraph IV exposure	No meaningful exposure from this expired patent
Current formulation relevance	Historical; product formulations have changed

The FDA's 2016 rule on consumer antiseptic washes did not itself determine the regulatory status of triclosan dentifrice products. Dentifrices are regulated through a separate framework involving anticaries monographs, approved drug applications, labeling requirements, and product-specific regulatory history.[1][2]

A key distinction is that FDA approval does not preserve patent rights, and patent expiration does not revoke FDA approval. A formulation may remain approvable or marketed under an applicable regulatory pathway after the patent has expired.

Which companies challenged or licensed this patent?

The patent record identifies the original assignee and inventors, but a complete commercial answer requires separating:

Assignment of the patent;
Licensing of the polymer or antibacterial technology;
Licensing of a finished dentifrice formulation;
Regulatory sponsorship of a drug application; and
Patent litigation or settlement activity.

The patent is associated with the Colgate-Palmolive technology portfolio and the triclosan/PVM/MA dentifrice platform. PVM/MA polymers were also commercially associated with ISP, later Ashland, through Gantrez-related products. Polymer supply relationships do not by themselves establish a license to the patent.

No current licensing restriction can arise from US Patent 5,776,435 after expiration. Any historical license, supply agreement, or settlement could have contractual terms surviving patent expiration, but those terms are separate from patent enforceability.

What patent litigation affects US Patent 5,776,435?

The patent's present litigation risk is effectively zero because the patent is expired. A patent owner cannot obtain prospective injunctive relief for ongoing conduct under an expired patent. Historical infringement claims, damages periods, settlement releases, and contractual disputes are legally distinct questions.

The key litigation issues that would have mattered during the patent term were:

Whether the accused toothpaste contained 0.25% to 0.35% triclosan;
Whether the abrasive was a qualifying siliceous polishing agent;
Whether the enhancer was PVM/MA or another covered anionic polymer;
Whether the formulation contained an effective polyphosphate anticalculus amount;
Whether a polyethylene glycol vehicle reduced antibacterial activity;
Whether the functional delivery and retention limitations were met; and
Whether prosecution history narrowed the broad functional language.

The absence of a current enforceable term eliminates the principal commercial value of an infringement action based solely on this patent.

How does this patent compare with later triclosan toothpaste patent estates?

US Patent 5,776,435 is a foundational composition patent focused on triclosan delivery and retention in a siliceous dentifrice. Later patent estates generally moved toward narrower improvements:

Patent-estate category	Typical subject matter
Active delivery	Increased triclosan substantivity or controlled release
Polymer systems	Alternative anionic polymers, salts, or polymer combinations
Abrasives	Silica morphology, cleaning performance, and compatibility
Fluoride compatibility	Stability of triclosan with sodium fluoride or other fluoride sources
Sensory properties	Flavor, foaming, viscosity, and mouthfeel
Packaging	Stability, tube materials, and preservation
Therapeutic indications	Plaque, gingivitis, caries, or periodontal-use claims
Product architecture	Multi-compartment or separate-active delivery

The '435 patent has broad foundational language but limited remaining commercial value. A later patent can still create risk if it claims a narrower formulation, process, delivery system, or use that remains unexpired. Freedom-to-operate analysis therefore cannot stop with the '435 patent.

What manufacturing and intellectual-property barriers remain?

The expired patent does not eliminate technical barriers. A competitor still must address:

Homogeneous incorporation of hydrophobic triclosan;
Compatibility between triclosan, silica, fluoride, surfactant, flavor oil, and humectant;
Polymer dispersion and hydration;
Long-term assay and degradation stability;
Preservation and microbial control;
Flavor retention;
Abrasivity and cleaning performance;
Tube and packaging compatibility; and
FDA formulation, labeling, and manufacturing requirements.

A substitute antibacterial agent may avoid the '435 claims but require new clinical, toxicological, stability, and regulatory work. A substitute polymer may avoid claim 18 while creating performance or process problems.

What generic launch scenarios exist?

Three commercial scenarios are most relevant:

Triclosan/PVM/MA toothpaste

This formulation would likely have been the closest historical target of claim 18. The patent's expiration removes the patent barrier, but regulatory status, product approval, labeling, and current consumer-market restrictions remain separate issues.

Non-triclosan antibacterial toothpaste

A product using stannous fluoride, zinc salts, essential oils, or another active may avoid the central triclosan limitations. Its risk shifts toward later formulation patents and regulatory requirements.

Non-dentifrice oral-care product

A mouthrinse, gel, varnish, lozenge, or professionally applied product may avoid the dentifrice limitation. Separate patents can cover those dosage forms.

Key Takeaways

US Patent 5,776,435 covers dentifrices containing triclosan or related noncationic antibacterial agents, silica abrasive, and an antibacterial delivery-and-retention enhancer.
Claim 18 is the key commercial claim because it specifically combines 0.25% to 0.35% triclosan with a maleic acid or maleic anhydride/methyl vinyl ether copolymer.
Claims 1 and 8 are broader in enhancer chemistry but depend more heavily on functional and structural interpretation.
Claims 4 through 6 narrow the polymer to methyl vinyl ether copolymers with specified molar ratios and molecular weights.
Claim 19 adds a fluoride source but does not convert the patent into a general fluoride toothpaste patent.
The patent expired approximately in 2014-2015 under the applicable 20-year statutory term.
The patent presents no current US injunction, Paragraph IV stay, or launch-blocking patent risk.
Historical commercial relevance centers on triclosan toothpaste technology, including the Colgate Total platform.
Current freedom-to-operate work must focus on later, unexpired patents covering alternative actives, polymers, delivery systems, abrasives, manufacturing, packaging, and therapeutic uses.

FAQs About US Patent 5,776,435

Does US Patent 5,776,435 still block triclosan toothpaste products?

No. The patent's US term has expired. It cannot independently block current manufacture, sale, or launch of a qualifying triclosan toothpaste.

Is PVM/MA still patent-protected by US Patent 5,776,435?

No. The patent's claims involving maleic acid or maleic anhydride copolymers, including methyl vinyl ether copolymers, are expired in the United States.

Did the patent cover Colgate Total toothpaste?

The claimed triclosan, silica, fluoride-compatible dentifrice architecture, and PVM/MA enhancer are closely associated with the technology used in historical triclosan toothpaste products, including Colgate Total. Product-specific infringement and regulatory conclusions require comparison with the approved formulation and historical product records.

Can a company file a Paragraph IV certification against this patent today?

An expired patent generally does not create a current Paragraph IV launch barrier. Paragraph IV practice is directed principally to unexpired listed patents identified in the relevant FDA application context.

What patent should be reviewed after US Patent 5,776,435?

The next review should cover unexpired US patents and applications relating to antibacterial toothpaste actives, stannous fluoride, zinc compounds, essential oils, PVM/MA substitutes, silica systems, polymer-assisted substantivity, manufacturing methods, packaging, and therapeutic-use claims.

References

Food and Drug Administration. (2016). Safety and effectiveness of consumer antiseptics; topical antimicrobial drug products for over-the-counter human use. 81 Fed. Reg. 61106.
Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.
United States Patent and Trademark Office. (1998). U.S. Patent No. 5,776,435, Oral compositions containing antibacterial agents and antibacterial enhancing agents. U.S. Department of Commerce.
United States Patent and Trademark Office. (2024). Patent Center: U.S. Patent No. 5,776,435. U.S. Department of Commerce.
Colgate-Palmolive Company. (1997). Colgate Total toothpaste: New drug application regulatory history. U.S. Food and Drug Administration.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	243371	⤷ Start Trial
Argentina	244259	⤷ Start Trial
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Details for Patent: 5,776,435

Summary for Patent: 5,776,435