United States Patent 8,574,622: Scope, Claims, Expiration, and Testosterone Nasal Gel Patent Landscape

U.S. Patent No. 8,574,622 covers a testosterone gel designed for nasal administration and controlled systemic delivery. Its broadest claim requires four formulation elements: testosterone, a lipophilic carrier, a surface-tension-lowering compound, and a viscosity regulator. Claim 7 is materially narrower and targets a formulation using castor oil, oleoyl macrogolglycerides, and colloidal silicon dioxide that maintains serum testosterone above baseline for at least six hours.

The patent is closely associated with the formulation technology used in Natesto, the FDA-approved nasal testosterone product marketed by Acerus Pharmaceuticals and developed originally by Trimel Pharmaceuticals. The principal infringement risk is formulation-based. A competing product could avoid literal infringement by omitting or replacing a required excipient, but the six-hour pharmacokinetic limitation in claim 7 creates a separate technical and evidentiary issue.

What does U.S. Patent 8,574,622 cover?

U.S. Patent 8,574,622, titled “Testosterone Gel Formulation,” covers pharmaceutical compositions for intranasal testosterone delivery. The patent does not broadly cover every nasal testosterone product. It requires a particular combination of active pharmaceutical ingredient and excipient classes.

Core claim elements

Element	Claim 1 requirement	Claim 7 requirement
Testosterone	About 0.5% to about 10% by weight	About 0.5% to about 6%
Lipophilic carrier	About 60% to about 98%	Castor oil, about 75% to about 95%
Surface-tension-lowering compound	About 1% to about 20%	Oleoyl macrogolglycerides, about 1% to about 5%
Viscosity regulator	About 0.5% to about 10%	Colloidal silicon dioxide, about 0.5% to about 5%
Administration	Nasal	Nasal
Delivery objective	Controlled systemic release	Controlled systemic release
Pharmacokinetic limitation	None expressly quantified	Serum testosterone remains above baseline for at least six hours

Claim 1 is an independent composition claim. Claims 2 through 6 narrow individual components of claim 1. Claim 7 is also independently drafted and does not merely depend on claim 1.

How broad is claim 1 of U.S. Patent 8,574,622?

Claim 1 has substantial compositional breadth but meaningful structural limitations. It requires:

Testosterone in a concentration of approximately 0.5% to 10% by weight.
At least one lipophilic or partly lipophilic carrier in a concentration of approximately 60% to 98%.
A surface-tension-decreasing compound or mixture in a concentration of approximately 1% to 20%.
A viscosity-regulating agent in a concentration of approximately 0.5% to 10%.
A gel formulation intended for nasal administration and controlled systemic testosterone release.

The claim uses the transitional term “comprising.” That term generally permits the presence of additional ingredients, provided the accused product still contains every required claim element. A competitor could therefore include preservatives, antioxidants, buffers, stabilizers, flavoring agents, or other excipients without automatically avoiding claim 1.

The percentages are expressed by weight of the total formulation. Formulation records, batch records, manufacturing specifications, and regulatory submissions would be central to determining whether a product falls within the claimed ranges.

What claim 1 does not require

Claim 1 does not expressly require:

Castor oil;
Oleoyl macrogolglycerides;
Colloidal silicon dioxide;
A particular testosterone dose per actuation;
A metered nasal pump;
A specific particle size;
A particular pH;
A specific viscosity value;
A specified dosing frequency;
A six-hour serum testosterone profile;
A particular nasal deposition site; or
A specific manufacturing process.

Those omissions expand claim 1 beyond the commercial formulation identified in claim 7.

What formulations are protected by claims 2 through 7?

Claims 2 through 6 create narrower fallbacks within claim 1.

Claim	Narrowing limitation	Commercial significance
2	The lipophilic carrier comprises an oil	Captures oil-based nasal gels
3	The oil is a vegetable oil	Narrows the carrier to plant-derived oils
4	The vegetable oil is castor oil	Directly targets a principal commercial carrier
5	The surface-tension agent is oleoyl macrogolglyceride or a mixture of such compounds	Targets a defined surfactant/excipient class
6	The viscosity regulator is colloidal silicon dioxide	Targets a common gel-structuring agent
7	Fixed ingredient identities, narrower percentage ranges, and six-hour pharmacokinetic performance	Provides a focused commercial formulation claim

Claim 7 is likely the most commercially relevant claim because it combines the specific ingredients associated with the marketed nasal gel with a performance requirement. Its narrower ranges may make it easier to design around, but the specific ingredient combination can make infringement analysis more direct if a competitor uses the same formulation architecture.

How should the percentage ranges be interpreted?

The ranges are approximate and overlap across the claims. For example, a formulation containing 4% testosterone, 85% castor oil, 3% oleoyl macrogolglycerides, and 2% colloidal silicon dioxide would fall within the express numerical ranges of claim 7, assuming the product satisfies the nasal administration and serum-level limitations.

The total ranges in claim 1 do not create a mathematical requirement that the four listed components total exactly 100%. The use of “comprising” means the formulation may contain other ingredients. The claim also does not state whether a listed mixture must be measured as a total excipient mixture or as each individual component. That issue could matter for a formulation containing several macrogolglycerides or multiple viscosity modifiers.

A product slightly outside a stated range may still raise a doctrine-of-equivalents issue, but the strength of that argument would depend on prosecution history, claim amendments, prior-art distinctions, and whether the numerical limitation was treated as critical.

What is the scope of claim 7’s six-hour limitation?

Claim 7 requires that the serum testosterone level achieved after nasal administration remain above the patient’s testosterone baseline for at least six hours.

This limitation creates several technical questions:

How is the patient’s baseline measured?
Is baseline determined immediately before dosing or from a separate pretreatment period?
Does one administration need to produce the six-hour result?
Must the result occur in every patient or only in a statistically defined population?
What assay and sampling schedule apply?
Does “above baseline” refer to total testosterone or free testosterone?
Does the limitation apply to a single dose or repeated dosing?

The claim language refers to “the patient,” which may support an infringement theory based on an individual patient’s result. A generic applicant or competitor would likely examine clinical pharmacokinetic data, label instructions, and formulation composition together. A product that contains the claimed ingredients but does not produce the six-hour profile may avoid literal infringement of claim 7 while remaining exposed under claim 1.

What is the FDA status of the related nasal testosterone product?

Natesto is a testosterone nasal gel approved by the FDA in May 2014 under NDA 205488. The product is indicated for replacement therapy in adult males with conditions associated with a deficiency or absence of endogenous testosterone. The FDA label identifies a metered nasal delivery system and a dosing regimen administered multiple times daily.[1]

Natesto is distinct from conventional transdermal testosterone gels such as AndroGel and Testim. It delivers testosterone through the nasal mucosa and avoids some of the skin-transfer concerns associated with topical shoulder or arm gels. The nasal route also creates different formulation requirements involving mucosal tolerability, viscosity, retention, surfactant selection, and systemic absorption.

The product label identifies testosterone as the active ingredient and describes a gel formulation administered intranasally through a pump device.[1] The formulation details in claim 7 align closely with the technical architecture associated with this product.

When does U.S. Patent 8,574,622 lose exclusivity?

Public patent records identify a priority date in February 2008 for the patent family. On a basic 20-year calculation from the earliest claimed priority date, the nominal term would extend into February 2029. The legally operative expiration date can differ because of patent-term adjustment, patent-term extension, terminal disclaimers, or changes in the recorded priority chain.[2]

Event	Date or status
Earliest publicly identified priority period	February 2008
U.S. patent issued	November 5, 2013
Nominal 20-year term calculation	February 2029
Patent-term adjustment	Must be taken from the USPTO patent record
Orange Book relevance	Depends on FDA listing and the approved product’s protected conditions of use
Regulatory exclusivity	Separate from patent term

Patent expiry does not by itself establish immediate generic market entry. FDA approval requirements, ANDA certification status, litigation stays, formulation development, manufacturing qualification, and any later-issued patents can affect the practical launch date.

What is the Orange Book status of U.S. Patent 8,574,622?

The patent is associated in public drug-patent databases with the Natesto testosterone nasal gel product. Orange Book treatment must be evaluated at the product level because FDA listings identify patents submitted for an approved drug, dosage form, or method of use.

For an Orange Book-listed patent, the relevant generic applicant may make one of four certifications:

Paragraph I: no patent information is listed;
Paragraph II: the patent has expired;
Paragraph III: the applicant will wait until patent expiration; or
Paragraph IV: the patent is invalid, unenforceable, or will not be infringed.

A Paragraph IV notice can trigger patent litigation under the Hatch-Waxman Act. If the NDA holder or patent owner files an action within the statutory period, FDA approval of the ANDA may be stayed for up to 30 months, subject to statutory exceptions and court developments.[3]

The supplied claim set does not establish whether an ANDA applicant has filed a Paragraph IV challenge, whether litigation has occurred, or whether a settlement agreement exists. Those matters are separate from claim construction and must be established from FDA records, court dockets, and SEC disclosures.

Which companies are associated with the patent and product?

The patent family is associated with Trimel Pharmaceuticals and the Natesto development program. Acerus Pharmaceuticals later commercialized Natesto in the United States. The relevant commercial and legal participants include:

Entity	Role
Trimel Pharmaceuticals	Original developer associated with the nasal testosterone technology
Acerus Pharmaceuticals	Commercialization and marketing company for Natesto
FDA	NDA review, approval, labeling, and Orange Book administration
USPTO	Patent examination, maintenance, term adjustment, and assignment records
Generic applicants	Potential ANDA filers and Paragraph IV challengers

Assignment history should be reviewed separately from inventorship and NDA ownership. Patent ownership, FDA sponsor status, and commercialization rights can reside with different entities.

How strong is the patent estate for nasal testosterone?

The 8,574,622 patent has moderate-to-strong value against a copycat formulation and weaker coverage against a materially redesigned product.

Strengths

Claim 1 covers broad excipient classes rather than one precise recipe.
The claim is directed to a nasal gel with controlled systemic release, matching the product’s core delivery concept.
“Comprising” language permits additional formulation ingredients.
Claims 4 through 6 identify commercially recognizable excipients.
Claim 7 provides a focused claim directed to a specific formulation and pharmacokinetic outcome.

Vulnerabilities

The claims do not cover every nasal testosterone dosage form.
A non-gel formulation may avoid the claims.
A competitor may substitute a non-lipophilic carrier or different oil.
A different surfactant system could avoid claims 5 and 7.
A different viscosity regulator could avoid claim 6 and claim 7.
Claim 7’s six-hour limitation may require complex pharmacokinetic proof.
Broad excipient combinations may face prior-art and written-description scrutiny.
Numerical-range validity may depend on the prosecution record and prior-art disclosures.

The strongest enforcement position would generally involve a product that uses testosterone, castor oil, oleoyl macrogolglycerides, and colloidal silicon dioxide within the claim 7 ranges and makes label or clinical claims consistent with six-hour systemic exposure.

What generic launch scenarios exist?

Scenario 1: Formulation copy

A generic product copies the castor-oil, oleoyl-macroglyceride, and colloidal-silicon-dioxide system. This creates the highest literal infringement risk, particularly under claim 7.

Scenario 2: Excipient substitution

A competitor retains testosterone and nasal gel delivery but substitutes another carrier, surfactant, or viscosity agent. This may avoid the narrower claims, although claim 1 could still apply if the substitute falls within the broader functional categories.

Scenario 3: Non-gel nasal formulation

A solution, suspension, emulsion, powder, or alternative nasal delivery system may avoid the “gel formulation” limitation. The product could still face other patents, regulatory comparability issues, or patent claims in related families.

Scenario 4: Different pharmacokinetic profile

A formulation falls within the ingredient ranges but does not sustain serum testosterone above baseline for six hours. That fact may defeat claim 7 but would not necessarily defeat claim 1, which lacks the express six-hour requirement.

Scenario 5: Post-expiration entry

An ANDA applicant waits for patent expiration and avoids Paragraph IV litigation. Entry timing would then depend on patent-term calculations, FDA approval, regulatory exclusivity, and any other unexpired listed patents.

What patent litigation and settlement risks affect Natesto?

A Paragraph IV challenge would likely focus on obviousness, anticipation, claim construction, written description, enablement, and the scope of any FDA-listed method-of-use claims. The most important technical evidence would include:

Prior-art nasal testosterone formulations;
Castor-oil and macrogolglyceride excipient disclosures;
Evidence that colloidal silicon dioxide was conventional in nasal gels;
Comparative absorption and retention data;
The necessity of the claimed excipient ranges;
The relationship between formulation composition and the six-hour serum profile;
Prosecution amendments and examiner reasons for allowance.

A settlement could include a licensed entry date, a supply arrangement, a covenant not to sue, or restrictions on product labeling. No settlement terms should be inferred from the patent claims alone.

How does this patent compare with transdermal testosterone patents?

Issue	U.S. 8,574,622 nasal gel	Conventional transdermal testosterone patents
Delivery route	Nasal mucosa	Skin
Primary formulation concern	Mucosal retention and absorption	Skin permeation and transfer control
Key excipient strategy	Oil, surfactant, viscosity regulator	Alcohol, penetration enhancer, solvent, polymer
Main safety concern	Nasal irritation and mucosal tolerability	Secondary transfer and skin exposure
Typical design-around	Change carrier or dosage form	Change permeation system or topical vehicle
Regulatory pathway	Nasal testosterone NDA/ANDA comparison	Transdermal gel or solution pathway

The patent’s commercial relevance derives from the combination of nasal delivery and a specific gel architecture. A transdermal testosterone product would not ordinarily infringe because it would lack the nasal-administration limitation.

Key Takeaways

U.S. Patent 8,574,622 protects a nasal testosterone gel rather than testosterone therapy generally.
Claim 1 is the principal broad composition claim.
Claims 2 through 6 narrow the carrier, surfactant, and viscosity-regulator elements.
Claim 7 targets a castor-oil formulation using oleoyl macrogolglycerides and colloidal silicon dioxide.
The six-hour serum testosterone requirement materially narrows claim 7 and creates proof issues.
The patent is linked to the Natesto nasal testosterone product and the Trimel/Acerus development and commercialization chain.
The earliest publicly identified priority period is February 2008, producing a nominal term into February 2029 before any patent-term adjustment or other statutory modification.
The greatest generic risk comes from a formulation that copies the claimed excipient system.
Excipient substitution, a non-gel dosage form, or a different pharmacokinetic profile may provide design-around paths.
Paragraph IV activity, Orange Book listing, litigation, settlements, and current patent-term calculations require separate review of FDA, USPTO, court, and transaction records.

FAQs About U.S. Patent 8,574,622

Does the patent cover all testosterone nasal sprays?

No. The claims require a gel formulation with specified formulation components and concentration ranges. A nasal solution, powder, suspension, or materially different gel may fall outside the claims.

Is castor oil mandatory under every claim?

No. Castor oil is required by claims 4 and 7, but claim 1 covers a broader class of lipophilic or partly lipophilic carriers. Claim 2 requires an oil, and claim 3 requires a vegetable oil.

Can a product infringe claim 1 without infringing claim 7?

Yes. Claim 1 has broader ingredient classes and ranges and does not require the six-hour serum testosterone limitation. A product may fall within claim 1 while avoiding claim 7’s specific ingredients, narrower ranges, or pharmacokinetic requirement.

Does FDA approval of Natesto prove patent validity?

No. FDA approval evaluates safety, efficacy, quality, and regulatory compliance. Patent validity and infringement are determined under patent law, generally by the USPTO and federal courts.

Can a generic launch before the nominal 2029 date?

Potentially. An applicant could prevail in Paragraph IV litigation, obtain a license or settlement allowing earlier entry, or demonstrate that its product does not infringe unexpired claims. Regulatory approval and other listed patents could still affect launch timing.

References

U.S. Food and Drug Administration. (2014). Natesto (testosterone) nasal gel: Prescribing information. FDA.
United States Patent and Trademark Office. (2013). U.S. Patent No. 8,574,622, Testosterone gel formulation. U.S. Department of Commerce.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. FDA.
U.S. Code. (2018). 35 U.S.C. §§ 154, 156, and 271(e). United States Code.
U.S. Code. (2018). 21 U.S.C. § 355(j). United States Code.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
	03025769	Nov 11, 2003

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	047722	⤷ Start Trial
Austria	E319426	⤷ Start Trial
Australia	2004286781	⤷ Start Trial
Brazil	PI0416370	⤷ Start Trial
Canada	2541498	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,574,622

Summary for Patent: 8,574,622