US Patent 9,101,592: Claim Scope, Patent Strength, Exclusivity and Generic Risk for Phlegmatized Nitroglycerin Powder

US Patent 9,101,592 protects a specific solid glyceryl trinitrate, or nitroglycerin, formulation in which phlegmatized GTN is combined with a low-melting, non-volatile polyethoxylated glyceride, absorbed onto a porous pharmaceutical carrier, and combined with oral or oromucosal excipients. The strongest commercial embodiments are free-flowing sublingual powders or granules containing approximately 0.05% to 2% GTN, oleoyl macrogol-glyceride, dibasic calcium phosphate, and isomalt.

The patent does not broadly cover every nitroglycerin tablet, spray, capsule, patch, or sublingual formulation. Infringement generally requires the accused product to contain the claimed combination of phlegmatized GTN, a qualifying polyethoxylated glyceride, and a porous carrier. The narrowest commercial claims, particularly claims 27 and 29, concentrate on the combination of dibasic calcium phosphate, isomalt, oleoyl macrogol-glyceride, and a homogeneous free-flowing absorbate.

What does US Patent 9,101,592 protect?

The patent protects a formulation platform rather than the GTN molecule itself. Its central technical concept is the preparation of a stable, free-flowing solid absorbate containing phlegmatized GTN.

The core elements are:

Claim element	Requirement
Active ingredient	Phlegmatized glyceryl trinitrate
GTN concentration	0.05% to 2% by weight in the principal dependent and independent embodiments
Lipidic excipient	At least one non-volatile polyethoxylated glyceride
Melting point	Not higher than 60°C
Carrier	Porous, pharmaceutically suitable carrier
Physical structure	Homogeneous admixture absorbed to the carrier
Dosage form	Solid preparation, powder, granules, or free-flowing absorbate
Administration	Oral or oromucosal, including sublingual use
Preferred carrier	Dibasic calcium phosphate
Preferred glyceride	Oleoyl macrogol-glyceride
Preferred sweetener or bulking agent	Isomalt
Packaging	Single-dose stick pack or sachet

The claims target both composition and manufacturing steps. This gives the patent two potential infringement theories: direct use or sale of the claimed formulation, and performance of the claimed manufacturing sequence.

How are the independent claims structured?

Claim 1: broad composition claim

Claim 1 requires:

A solid pharmaceutical preparation.
A homogeneous admixture.
Phlegmatized GTN.
At least one non-volatile polyethoxylated glyceride.
A melting point of no more than 60°C for that glyceride.
Absorption of the admixture onto a porous pharmaceutical carrier.

This is the principal platform claim. It does not require isomalt, dibasic calcium phosphate, a specific GTN concentration, a flavor, or a particular dosage form. A product could fall within claim 1 even if it uses a different porous carrier and a different qualifying polyethoxylated glyceride.

The important limitation is the relationship among the ingredients. A simple physical mixture of GTN and an excipient may not satisfy the claim if the GTN-glyceride admixture is not absorbed to a porous carrier. Conversely, a product may present a risk even if its marketing description does not use the term "absorbate," provided the physical formulation meets the claim construction adopted by a court.

Claims 2 through 6: GTN concentration

These claims narrow claim 1 by specifying GTN content:

Claim	GTN content
2	0.05% to 2%
3	0.1% to 1%
4	0.2%
5	0.15%
6	0.1%

The nested concentration claims create fallback positions if the broad formulation claim is challenged. A product containing 0.15% GTN, for example, would fall within claims 2, 3, and 5 if all other limitations are met.

Claims 7 through 12: glyceride and ratio limitations

Claim 7 requires the polyethoxylated glyceride to be solid or semi-solid at 20°C. Claim 8 limits glyceride content to 0.2% to 10% by weight. Claim 9 identifies oleoyl macrogol-glyceride, and claim 10 fixes that ingredient at 2% by weight.

Claim 11 requires a glyceride-to-GTN mass ratio of 2:1 to 40:1. Claim 12 requires a diluent-to-glyceride ratio of 1:1 to 9.5:1.

These ratios are commercially relevant because they can be tested through formulation records, quantitative assay, and reverse engineering. They also narrow the claims to formulations in which the glyceride is present at a meaningful level rather than as a trace processing aid.

Claims 13 and 14: porous carrier limitations

Claim 13 identifies three carriers:

Dibasic calcium phosphate
Magnesium aluminometasilicate
Isomalt

Claim 14 narrows the carrier to dibasic calcium phosphate.

Dibasic calcium phosphate is particularly important because claims 27 and 29 also require it. A competing product that uses silica, microcrystalline cellulose, lactose, or another carrier may avoid these narrow claims, although it could still implicate claim 1 if the alternative material is a porous pharmaceutical carrier.

Claims 15 through 19: sublingual excipients

Claim 15 introduces excipients suitable for sublingual administration. Claims 16 through 19 identify sugars and sugar alcohols, including:

Isomalt
Xylitol
Mannitol
Sorbitol
Sucrose
Fructose
Glucose
Lactose
Maltose
Maltitol
Trehalose

Claim 18 requires isomalt at 70% to 95% by weight. Claim 19 covers a composition containing both isomalt and xylitol, with the two excipients together representing 20% to 95% by weight.

These claims materially narrow the patent to high-bulk sweetener formulations. They are most relevant to powder or granule products intended for direct oral or sublingual administration.

Claims 20 through 23: dosage form, packaging, and flavor

Claim 20 covers free-flowing powder or granules. Claim 21 specifies single-dose stick packs or sachets. Claim 22 requires 0.01% to 3.0% flavoring agent, and claim 23 identifies peppermint.

Packaging is a meaningful limitation. A product sold only as a compressed tablet may not infringe claim 21, although it may still implicate other claims if its internal composition satisfies them.

Claims 24 through 26: manufacturing method

Claim 24 covers a three-step process:

Admix phlegmatized GTN with the polyethoxylated glyceride.
Absorb the admixture onto the porous carrier.
Mix the absorbate with the excipient.

Claims 25 and 26 narrow the method to oleoyl macrogol-glyceride and isomalt.

These claims can create risk even where the final product is difficult to distinguish analytically. Manufacturing records, batch instructions, process validation documents, and supplier specifications may establish whether the claimed sequence was used.

Claims 27 through 29: commercially focused product claims

Claims 27 and 29 are directed to a narrower formulation containing:

0.05% to 2% phlegmatized GTN
Dibasic calcium phosphate
Isomalt
A non-volatile polyethoxylated glyceride

Claim 29 specifically requires oleoyl macrogol-glyceride. Both claims require a homogeneous, free-flowing absorbate.

Claim 28 requires:

0.05% to 2% GTN
0.2% to 10% polyethoxylated glyceride
70% to 95% excipient
0.01% to 3.0% flavoring agent

The "consisting essentially of" language in claim 28 excludes components that materially alter the basic and novel characteristics of the claimed formulation. It does not necessarily exclude every additional ingredient, but an accused product containing substantial additional functional components could create a claim-construction dispute.

What formulations are protected by US 9,101,592?

The highest-risk formulation is a single-dose sublingual powder containing approximately 0.1% to 0.2% GTN, 2% oleoyl macrogol-glyceride, dibasic calcium phosphate, and isomalt.

A representative claim-mapping example is:

Formulation characteristic	Claim exposure
0.15% phlegmatized GTN	Claims 2, 3, and 5
2% oleoyl macrogol-glyceride	Claims 8, 9, and 10
Dibasic calcium phosphate carrier	Claims 13, 14, 27, and 29
Isomalt at 70% to 95%	Claims 15 through 18
Free-flowing powder	Claim 20
Sachet or stick pack	Claim 21
Peppermint flavor	Claim 23
Claimed mixing and absorption sequence	Claims 24 through 26
Full combination with flavoring	Claim 28
Exact preferred combination	Claim 29

A formulation containing GTN and isomalt but no polyethoxylated glyceride would generally fall outside the express combination required by claim 1. A formulation containing a polyethoxylated glyceride but using a nonporous carrier may also avoid the principal composition claim, subject to the factual meaning of "porous" and "absorbed."

How strong is the patent estate?

The patent has moderate formulation protection and weaker molecule-level exclusivity.

Strengths

The claims combine several physical and compositional limitations:

Phlegmatized rather than generic GTN
A defined class of polyethoxylated glycerides
A melting-point ceiling
Absorption onto a porous carrier
Free-flowing powder or granule characteristics
Specific excipient and carrier combinations
A defined manufacturing sequence

That combination can make literal design-around difficult for a company seeking to reproduce the same powder technology.

The dependent claims also provide useful fallback positions. If a broad claim is found obvious, the patent owner can rely on the narrower combination of oleoyl macrogol-glyceride, dibasic calcium phosphate, and isomalt.

Weaknesses

The patent does not claim GTN as a chemical compound. It does not cover conventional nitroglycerin tablets, transdermal patches, ointments, metered sprays, or every sublingual dosage form.

Several terms may generate claim-construction disputes:

"Homogeneous admixture"
"Absorbed"
"Porous"
"Free-flowing"
"Phlegmatized"
"Non-volatile"
"Polyethoxylated glyceride"

The breadth of claim 1 also creates potential validity pressure. Prior art involving stabilized nitroglycerin, lipidic excipients, porous adsorbents, pharmaceutical powders, or sugar-based sublingual dosage forms could be combined in an obviousness challenge under 35 U.S.C. §103.

When does US Patent 9,101,592 lose exclusivity?

The patent number alone does not establish the enforceable expiration date. The relevant term depends on the earliest effective nonprovisional priority date, any patent-term adjustment, terminal disclaimer, patent-term extension, and post-grant status. The statutory baseline for a modern US utility patent is generally 20 years from the earliest effective US nonprovisional filing date under 35 U.S.C. §154.

The patent should therefore be analyzed through the complete prosecution record rather than the issue date. An issued patent can also be narrowed, cancelled, or otherwise affected by post-grant proceedings, disclaimers, or court judgments.

Patent-term analysis should include:

Term issue	Relevance
Earliest priority filing	Establishes the starting point for the 20-year term
US nonprovisional filing	Controls term calculation under the governing statute
Patent-term adjustment	Can extend the nominal expiration date
Terminal disclaimer	Can tie expiration to another patent
Patent-term extension	Potentially relevant if statutory requirements are met
Reexamination or post-grant review	May alter enforceable claim scope
Maintenance fees	Nonpayment can cause expiration before the nominal term

What is the Orange Book status of US 9,101,592?

A patent number is not itself an Orange Book listing. FDA Orange Book listing depends on whether the patent is submitted by an NDA holder for an approved drug product and accepted for publication under FDA’s patent-listing rules.

The patent’s formulation claims could be relevant to an NDA product only if the approved product uses the claimed formulation and the NDA holder submitted the patent in accordance with 21 C.F.R. §314.53. A patent may remain enforceable against an infringing product even if it is not listed in the Orange Book, but the absence of listing can affect the statutory ANDA certification and litigation pathway.

For an ANDA, a Paragraph IV challenge typically requires a certification that the listed patent is invalid, unenforceable, or will not be infringed. If the patent is not listed for the reference product, the applicant may not face the same Paragraph IV filing structure for that patent.

Which companies are challenging US 9,101,592?

The supplied patent information does not establish a named Paragraph IV challenger, ANDA litigation, inter partes review, post-grant review, or settlement involving US 9,101,592. No challenger should be identified without a verified USPTO, FDA, PACER, or district-court record.

The relevant competitive groups are:

Generic manufacturers developing nitroglycerin oral or sublingual products.
NDA holders with approved GTN tablets, sprays, capsules, patches, or ointments.
Contract manufacturers with powder-handling and containment capabilities.
Companies developing alternative sublingual delivery systems.

Conventional nitroglycerin products are not automatically relevant infringement comparators. The decisive issue is whether their formulation contains the claimed phlegmatized GTN-polyethoxylated glyceride absorbate on a porous carrier.

What generic launch risks exist?

Direct formulation replication

A generic company faces the highest risk if it copies the preferred formulation architecture:

0.1% to 0.2% phlegmatized GTN
Oleoyl macrogol-glyceride
Dibasic calcium phosphate
Isomalt
Free-flowing absorbate
Sachet or stick-pack presentation

That design could implicate claims 1, 2, 3, 4, 6, 8, 9, 10, 13, 14, 15, 17, 18, 20, 21, 24 through 26, 27, and 29 depending on the exact composition and process.

Design-around options

Potential design-around strategies include:

Using a different GTN stabilization or phlegmatization system.
Omitting the polyethoxylated glyceride.
Selecting a glyceride outside the claimed physical and chemical class.
Using a nonporous or materially different carrier.
Replacing dibasic calcium phosphate with another carrier.
Using a compressed tablet, liquid spray, or film rather than a free-flowing powder.
Replacing isomalt with a different excipient.
Changing the manufacturing sequence so that the claimed absorbate is not formed.

Each approach requires technical confirmation. A nominally different excipient will not avoid risk if it is legally and functionally within the claimed class.

What manufacturing and IP barriers matter?

The key manufacturing barrier is safe handling of GTN during phlegmatization, adsorption, blending, and unit-dose packaging. The process must control:

GTN concentration uniformity
Explosive-material exposure
Static electricity
Localized concentration or hot spots
Blend segregation
Moisture
Powder flow
Content uniformity
Packaging-dose accuracy

The patent’s process claims are relevant because the technology is defined partly by how the GTN-glyceride admixture is formed and absorbed. A competitor may avoid literal process infringement by using a different order of addition, a different carrier-loading operation, or a different stabilization system, but the final composition can still create product-claim exposure.

How does this patent compare with conventional GTN patents?

Technology	Typical protection focus	Relationship to US 9,101,592
Nitroglycerin compound	Chemical active ingredient	Generally expired or not the focus of this patent
Sublingual GTN tablet	Tablet composition and dissolution	May avoid the powder absorbate claims
Nitroglycerin spray	Metered delivery device and solution	Usually outside the claimed solid preparation
Transdermal GTN patch	Adhesive matrix and release profile	Separate patent category
GTN powder or granule	Stabilization, carrier, flow, and dose uniformity	Closest technology and highest risk
Manufacturing process	Mixing, adsorption, and excipient addition	Directly addressed by claims 24 through 26

Key Takeaways

US 9,101,592 is a formulation and process patent for solid, free-flowing phlegmatized GTN preparations.
The central combination is phlegmatized GTN, a qualifying non-volatile polyethoxylated glyceride, and a porous carrier.
Oleoyl macrogol-glyceride, dibasic calcium phosphate, and isomalt are the principal preferred commercial elements.
Claims 27 and 29 are especially important for a sublingual powder using the preferred ingredients.
Conventional GTN tablets, sprays, patches, and ointments are not automatically covered.
A generic developer can reduce risk through a different carrier, glyceride system, excipient, dosage form, or manufacturing sequence.
Orange Book relevance depends on an NDA submission and FDA listing, not merely on the existence of the patent.
The enforceable expiration date requires review of priority, prosecution, patent-term adjustment, terminal disclaimers, and post-grant records.
No verified Paragraph IV challenge or settlement should be inferred from the patent claims alone.

FAQs

Does US 9,101,592 cover all nitroglycerin sublingual products?

No. The claims require a specific solid absorbate architecture involving phlegmatized GTN, a non-volatile polyethoxylated glyceride, and a porous carrier.

Is oleoyl macrogol-glyceride required in every claim?

No. Claim 1 covers a broader class of qualifying polyethoxylated glycerides. Oleoyl macrogol-glyceride is required only in narrower claims such as claims 9, 10, 25, and 29.

Can a product avoid the patent by changing isomalt to xylitol?

Possibly, but not automatically. Claims 1 and 27 do not require isomalt, and a product with xylitol could still infringe broader claims if the GTN-glyceride porous-carrier structure is present.

Does a stick pack create patent infringement by itself?

No. The stick-pack limitation appears in claim 21. Packaging alone is insufficient; the product must also satisfy the underlying formulation limitations.

Could a compressed sublingual tablet infringe this patent?

Yes, if its internal composition satisfies the relevant claims and qualifies as the claimed absorbed solid preparation. A tablet format, however, may avoid claims specifically requiring a free-flowing powder or granules.

References

U.S. Patent No. 9,101,592, claims 1-29. United States Patent and Trademark Office.
U.S. Patent Act, 35 U.S.C. §§ 103, 154, 271.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
U.S. Food and Drug Administration. (2024). 21 C.F.R. § 314.53: Submission of patent information. FDA.
U.S. Patent and Trademark Office. (2024). Manual of Patent Examining Procedure, patent term adjustment and patent term extension provisions. USPTO.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Pohl Boskamp	GONITRO	nitroglycerin	POWDER;SUBLINGUAL	208424-001	Jun 8, 2016		DISCN	Yes	No	⤷ Start Trial	⤷ Start Trial	Y				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Germany	10 2011 012 491	Feb 25, 2011

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2012219925	⤷ Start Trial
Australia	2012219926	⤷ Start Trial
Canada	2827714	⤷ Start Trial
Canada	2827716	⤷ Start Trial
European Patent Office	2678000	⤷ Start Trial
European Patent Office	2678006	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,101,592

Which drugs does patent 9,101,592 protect, and when does it expire?

Summary for Patent: 9,101,592