# United States Patent 5,811,120: Raloxifene Hydrochloride Formulation Scope, Expiration, and Patent Landscape

U.S. Patent No. 5,811,120 covers solid raloxifene hydrochloride formulations containing a specified surfactant, polyvinylpyrrolidone, and a water-soluble diluent. The broadest independent claims require either a sorbitan fatty acid ester or a polyoxyethylene sorbitan fatty acid ester, together with a polyol or sugar. Dependent claims narrow the formulation to polysorbate 80, lactose, magnesium stearate, cross-linked polyvinylpyrrolidone, film coating, and tablet or capsule dosage forms.

The patent is an expired U.S. formulation patent. Its term was tied to a November 1995 priority date and ended in 2015, subject to any applicable patent-term adjustment or pediatric extension. It does not currently block generic raloxifene hydrochloride tablets or capsules. The patent remains relevant as a technical and historical reference for the formulation design of Evista, but it does not provide current U.S. market exclusivity.

What does U.S. Patent 5,811,120 protect?

The patent protects a composition, not raloxifene hydrochloride as a molecule and not every oral raloxifene formulation.

The central claimed combination is:

Raloxifene hydrochloride;
A qualifying surfactant;
Polyvinylpyrrolidone, commonly called povidone;
A water-soluble diluent that is a polyol or sugar.

The claim set also covers narrower combinations with lubricants, disintegrants, film coatings, tablets, and capsules.

The patent’s practical objective was to improve the manufacturability and oral pharmaceutical performance of raloxifene hydrochloride, particularly through excipient selection and solid dosage-form processing. The claims focus on the formulation architecture rather than a specific manufacturing step or therapeutic indication.

How are the independent claims structured?

Claims 1, 13, and 16 are the principal composition claims.

Claim	Claim type	Required formulation elements	Key limitation
1	Open-ended composition claim	Raloxifene hydrochloride, surfactant, povidone, water-soluble diluent	Surfactant must be sorbitan fatty acid ester or polyoxyethylene sorbitan fatty acid ester; diluent must be polyol or sugar
13	“Consisting essentially of” composition claim	Same core ingredients as claim 1	Excludes ingredients that materially alter the basic and novel characteristics of the formulation
16	Narrow composition claim	Raloxifene hydrochloride, polysorbate 80, lactose, povidone, magnesium stearate	Fixed excipient combination

Claim 1 is the broadest independent claim. Claim 13 uses “consisting essentially of,” which narrows the permissible additional ingredients compared with the “comprising” language in claim 1. Claim 16 is substantially narrower because it identifies specific excipients rather than generic excipient classes.

What does claim 1 require for infringement?

A product would generally need to satisfy every limitation of claim 1. The formulation must contain:

Raloxifene hydrochloride;
A sorbitan fatty acid ester or a polyoxyethylene sorbitan fatty acid ester;
Polyvinylpyrrolidone;
A water-soluble polyol or sugar.

The claim does not require:

A particular raloxifene dose;
A specified dissolution profile;
A particular particle size;
A particular manufacturing process;
A specific therapeutic indication;
A film coating;
A tablet or capsule presentation.

The claim is therefore composition-focused and potentially reaches multiple solid oral dosage forms if they contain the required excipient classes.

A formulation containing lactose, povidone, and polysorbate 80 would fall within the literal ingredient categories of claim 1, assuming the raloxifene active ingredient is raloxifene hydrochloride. A formulation using a different surfactant, such as sodium lauryl sulfate, would not literally satisfy the specified surfactant limitation, although doctrine-of-equivalents questions would depend on the product, prosecution history, and applicable legal analysis.

How do the dependent claims narrow the patent scope?

The dependent claims create progressively narrower commercial embodiments.

Surfactant limitations

Claims 2, 3, 5, 7, 11, 14, and 16 narrow the surfactant requirement.

Claim 2 requires a polyoxyethylene sorbitan fatty acid ester.
Claim 3 specifies polysorbate 80.
Claims 7 and 11 carry the polysorbate 80 or polyoxyethylene sorbitan limitation into formulations containing additional excipients.
Claim 16 directly requires polysorbate 80.

Polysorbate 80 is also known as polyoxyethylene sorbitan monooleate. The claim language uses a functional chemical class, then narrows to a specific excipient.

Diluent limitations

Claims 4, 6, 12, 15, and 16 narrow the diluent.

Claim 4 requires a sugar.
Claim 6 specifies lactose.
Claims 12 and 15 require a sugar in combination with other limitations.
Claim 16 specifies lactose.

A formulation using mannitol or sorbitol may fall within claim 1 if those materials are treated as the claimed polyol and all other limitations are present. A formulation using lactose is more directly exposed to the narrower lactose claims.

Lubricant and disintegrant limitations

Claims 8, 9, and 10 add conventional tablet excipients.

Claim 10 requires:

Magnesium stearate or stearic acid as the lubricant; and
Cross-linked polyvinylpyrrolidone as the disintegrant.

Cross-linked polyvinylpyrrolidone is commonly known as crospovidone. The claims distinguish ordinary povidone, which is required as a core formulation component, from cross-linked povidone, which is separately recited as a disintegrant.

Film coating and dosage-form limitations

Claims 17 through 20 add a film coating to selected formulations. Claims 21 through 33 require the formulation to be in tablet or capsule form.

These claims are narrower than the underlying composition claims. A coated tablet containing the full claim 16 formulation could implicate claims 16, 20, and 29, depending on how the product is characterized and the claim dependency is applied.

What is the difference between “comprising” and “consisting essentially of”?

Claims 1 and 16 use “comprising,” which is open-ended. A product may contain additional ingredients and still fall within the claim if it contains all recited elements.

Claim 13 uses “consisting essentially of.” This permits additional components only if they do not materially affect the basic and novel characteristics of the claimed raloxifene formulation. The phrase creates a narrower scope than “comprising,” but its application depends on the formulation’s technical characteristics and the role of the added ingredient.

The distinction matters for generic products because a manufacturer cannot avoid claim 1 merely by adding another excipient. An added excipient may be more relevant to claim 13, where the effect of the additional component becomes material.

What formulations are most directly covered by U.S. Patent 5,811,120?

The formulation most closely aligned with the narrow claims is a coated raloxifene hydrochloride tablet containing:

Raloxifene hydrochloride;
Polysorbate 80;
Lactose;
Povidone;
Magnesium stearate;
Crospovidone;
A film coating.

That formulation maps directly to the technical combination in claim 16 and the coating and dosage-form claims that depend on related formulations.

Formulation design	Principal claim exposure
Raloxifene hydrochloride + polysorbate 80 + povidone + lactose	Claims 1, 3, 6, 7, 14, 15, and potentially 16
Same formulation plus lubricant and disintegrant	Claims 8-12 and related dependent claims
Same formulation plus film coating	Claims 17-20
Same formulation in tablet or capsule form	Claims 21-33, depending on the dependency chain
Raloxifene hydrochloride + nonclaimed surfactant	Reduced literal exposure to claim 1
Raloxifene hydrochloride without povidone	Outside the express combination required by the claims
Raloxifene free base rather than hydrochloride	Potentially outside the literal active-ingredient limitation

The claims do not cover all raloxifene dosage forms. A formulation using raloxifene free base, a noncovered surfactant, no povidone, or a non-polyol/non-sugar diluent may avoid literal infringement of the principal claims.

When did U.S. Patent 5,811,120 lose exclusivity?

The patent issued on September 22, 1998, and was based on a November 1995 priority date. The ordinary 20-year patent term therefore ended in November 2015, subject to any term adjustment or extension reflected in the official USPTO record.[1]

For commercial purposes, the patent should be treated as expired in the United States. Any pediatric exclusivity associated with raloxifene would have been a separate regulatory period and would not revive the patent after expiration. Patent expiration removes the enforceable patent barrier, although it does not eliminate other regulatory requirements for an ANDA applicant.

Event	Date or status
Earliest reported priority period	November 1995
U.S. patent application and prosecution	1990s
Patent issued	September 22, 1998
Ordinary 20-year term endpoint	November 2015
Current U.S. patent status	Expired
Current ability to support a Paragraph IV injunction	None based on this patent alone

The exact expiration date should be taken from the USPTO patent term record when calculating historical damages, launch timing, or an earlier generic entry date. The November 2015 endpoint is the commercially relevant term conclusion.

What was the Orange Book status of U.S. Patent 5,811,120?

U.S. Patent 5,811,120 was associated with the Evista raloxifene hydrochloride product and was part of the historical formulation patent landscape for the drug.[2] The relevant reference product was Evista, originally sponsored by Eli Lilly and Company under NDA 020815.[3]

The Orange Book listing of a formulation patent does not mean that every generic raloxifene product infringes. An ANDA applicant may certify that the patent is invalid, unenforceable, or not infringed under Paragraph IV of the Hatch-Waxman Act. The practical relevance of this patent has now ended because the patent term expired.

The regulatory status should be separated into three categories:

Issue	Status
Active ingredient exclusivity	Expired
U.S. formulation patent 5,811,120	Expired
Current Orange Book blocking effect	None from this patent
ANDA pathway	Available for generic raloxifene hydrochloride products, subject to FDA requirements
Biosimilar pathway	Not applicable

Were there Paragraph IV challenges to this patent?

Paragraph IV certification was legally available for ANDA applicants while the patent was listed and unexpired. A Paragraph IV certification could assert that U.S. Patent 5,811,120 was invalid, unenforceable, or would not be infringed by the proposed generic formulation.

The statutory 30-month stay applies only when the patent holder or NDA holder brings a timely infringement action after receiving the Paragraph IV notice. Once the patent expired, the patent could no longer support a prospective injunction against generic entry.

Public records should distinguish among:

A Paragraph IV certification directed to the patent;
A patent litigation complaint;
A settlement agreement;
A commercial launch before patent expiration;
A launch after patent expiration.

A generic company’s ANDA filing or Paragraph IV certification does not establish infringement. It establishes the legal basis for challenging the listed patent.

Which companies challenged the Evista patent estate?

The historical Evista generic market included multiple ANDA applicants and generic manufacturers. The commercially important competitive group included Teva, Watson/Actavis, Mylan, Sandoz, and other suppliers of raloxifene hydrochloride tablets.

The existence of generic competition does not by itself show that each company challenged U.S. Patent 5,811,120. ANDA applicants may rely on Paragraph III certification, Paragraph IV certification, a patent expiration date, or a different regulatory strategy. Company-specific litigation and settlement conclusions require docket-level matching of each ANDA notice to the patent number.

There is no current litigation risk from U.S. Patent 5,811,120 because the patent has expired. Any historical case involving the patent would have to be evaluated under its filing date, asserted claims, settlement terms, and the expiration date.

How strong was the patent estate for raloxifene formulations?

The patent had moderate historical strength against products that copied the excipient profile but limited strength against materially different formulations.

Strengths

Claim 1 covers a broad combination of active ingredient and excipient classes.
Polysorbate 80 and lactose are expressly identified in dependent claims.
The claims cover both tablets and capsules.
The formulation claims do not require a particular therapeutic use.
Open-ended “comprising” language reduces the effectiveness of simple additive design-arounds.

Limitations

Every required ingredient must be present for literal infringement.
The patent does not cover raloxifene hydrochloride as an active pharmaceutical ingredient by itself.
It does not require or claim a specific dissolution result.
It does not claim all surfactants or all soluble diluents.
It does not claim a manufacturing process.
The patent term has expired.

The most effective historical design-arounds would have involved changing the surfactant, removing povidone, replacing the soluble diluent, or using a materially different dosage-form architecture.

What generic launch scenarios existed?

Before expiration, the main generic launch scenarios were:

Paragraph III launch: The applicant accepted the patent and deferred launch until expiration.
Paragraph IV launch: The applicant challenged validity, enforceability, or infringement and sought launch before expiration.
Noninfringing formulation launch: The applicant used a formulation outside the literal scope of the claims.
Settlement-based launch: The applicant resolved the dispute under agreed entry terms.
Post-expiration launch: The applicant entered after November 2015 or the applicable adjusted term.

After expiration, the principal barriers became FDA bioequivalence, chemistry and manufacturing controls, product quality, supply reliability, and commercial pricing. Patent-based launch risk from the ’120 patent ceased.

Does the patent create biosimilar risk?

No. Raloxifene hydrochloride is a synthetic small-molecule drug, not a biologic. The relevant competitive pathway is an ANDA under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not a biosimilar application under section 351(k) of the Public Health Service Act.

The principal post-expiration competitors are generic tablet manufacturers. Biosimilar concepts such as reference-product exclusivity, interchangeability, and biologic licensing do not apply to this patent or to Evista.

What manufacturing and intellectual-property barriers remain?

The ’120 patent does not currently create a manufacturing barrier. It also does not claim a process that would prevent a manufacturer from producing raloxifene hydrochloride tablets using a different process.

Remaining technical barriers can include:

Uniform dispersion of the low-dose active ingredient;
Control of blend uniformity;
Tablet hardness and friability;
Dissolution and disintegration performance;
Stability of the formulation;
Control of surfactant content;
Scale-up of granulation or blending;
Consistent bioequivalence performance.

These are regulatory and operational barriers, not enforceable exclusivity rights under the expired patent.

How does U.S. Patent 5,811,120 compare with other raloxifene patents?

Patent category	Subject matter	Current commercial relevance
Active-ingredient or composition patents	Raloxifene chemical entity or salt	Expired for the original product estate
Formulation patent 5,811,120	Solid raloxifene hydrochloride formulation with specified excipients	Expired
Method-of-use patents	Treatment or prevention indications	Must be assessed separately; this patent does not claim a method of use
Manufacturing patents	Synthesis, purification, or processing	Separate rights and expiration dates
Regulatory exclusivity	FDA exclusivity periods	Separate from patent rights and generally expired for Evista

Patent 5,811,120 should not be treated as a method-of-use patent, a polymorph patent, or a manufacturing patent. Its scope is limited to the claimed solid formulation combinations.

Key Takeaways

U.S. Patent 5,811,120 claims solid raloxifene hydrochloride formulations.
Claim 1 requires raloxifene hydrochloride, povidone, a qualifying sorbitan-based surfactant, and a polyol or sugar.
Polysorbate 80, lactose, magnesium stearate, crospovidone, film coatings, tablets, and capsules are covered by narrower dependent claims.
Claim 16 is the narrowest commercially important formulation claim and specifically requires polysorbate 80, lactose, povidone, and magnesium stearate.
The patent does not claim raloxifene hydrochloride generally, every raloxifene formulation, or any therapeutic method.
The patent expired in 2015 based on its November 1995 priority period, subject to the official term record.
It creates no current U.S. patent barrier to generic raloxifene entry.
Paragraph IV certification was historically available, but the patent cannot now support a prospective injunction.
Raloxifene is a small molecule, so biosimilar analysis is not applicable.
Current competitive barriers are primarily FDA approval, bioequivalence, manufacturing quality, supply, and price.

FAQs About U.S. Patent 5,811,120

Does U.S. Patent 5,811,120 cover Evista itself?

It covers certain solid Evista-type formulations, not raloxifene hydrochloride as a molecule. Coverage depends on the formulation’s excipient composition.

Can a generic raloxifene tablet use lactose and povidone?

Yes, but the product must be assessed for the complete combination of claimed ingredients, including the specified surfactant and other limitations. The expired status of the patent removes current infringement risk from this patent.

Is polysorbate 80 required in every claim?

No. The broadest claim permits either a sorbitan fatty acid ester or a polyoxyethylene sorbitan fatty acid ester. Polysorbate 80 appears in narrower claims.

Does the patent cover raloxifene capsules?

Yes. Claims 21 through 33 extend selected formulation claims to tablets or capsules.

Are raloxifene method-of-use patents included in the ’120 patent?

No. The ’120 patent is directed to solid pharmaceutical formulations. Therapeutic-use claims would belong to separate patents.

References

United States Patent and Trademark Office. (1998). U.S. Patent No. 5,811,120: Pharmaceutical compositions containing raloxifene.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (n.d.). Evista (raloxifene hydrochloride) prescribing information, NDA 020815.
U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application regulatory requirements.
U.S. Code, 35 U.S.C. §§ 154, 156.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	211910	⤷ Start Trial
Australia	1354895	⤷ Start Trial
Australia	684882	⤷ Start Trial
Brazil	9500758	⤷ Start Trial
Canada	2143263	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,811,120

Summary for Patent: 5,811,120