Details for Patent: 7,700,128

Which drugs does patent 7,700,128 protect, and when does it expire?

Patent 7,700,128 protects DUETACT and is included in one NDA.

This patent has thirty-four patent family members in twenty-eight countries.

Summary for Patent: 7,700,128

Title:	Solid preparation comprising an insulin sensitizer, an insulin secretagogue and a polyoxyethylene sorbitan fatty acid ester
Abstract:	A solid preparation useful as a diabetes-treating agent or the like and excellent in the dissolution properties of an insulin sensitizer and an insulin secretagogue, which comprises an insulin sensitizer, an insulin secretagogue and a polyoxyethylene sorbitan fatty acid ester is provided.
Inventor(s):	Kazuhiro Doken, Tetsuya Kawano, Hiroyoshi Koyama, Naoru Hamaguchi
Assignee:	Takeda Pharmaceutical Co Ltd
Application Number:	US10/544,581
Patent Claim Types: see list of patent claims	Compound;

US Patent 7,700,128: Scope, Claim Construction, Expiration, and Pioglitazone-Glimepiride Patent Landscape

US Patent 7,700,128 protects a multilayer solid dosage form combining pioglitazone, preferably pioglitazone hydrochloride, with glimepiride and Polysorbate 80. The patent is formulation-specific. It does not broadly claim the chemical combination of pioglitazone and glimepiride, a method of treating diabetes, or every fixed-dose tablet containing both drugs.

The central limitation is a layered solid preparation in which the glimepiride-containing layer includes Polysorbate 80 at 0.01% to 30% by weight of the total solid preparation. Claims 4 and 5 narrow the Polysorbate 80 range to 0.05% to 20% and 0.2% to 1%, respectively.

Based on the statutory patent term associated with the underlying international filing, the patent’s ordinary term expired in November 2023. The patent therefore presents limited current blocking risk unless a patent-term adjustment, extension, or related unexpired family member applies.

What does US Patent 7,700,128 protect?

The patent protects a solid, multilayer pharmaceutical preparation with four required structural and compositional elements:

1. A layer containing pioglitazone or a salt of pioglitazone.
2. A separate layer containing glimepiride.
3. Polysorbate 80 in the glimepiride-containing layer.
4. Polysorbate 80 present at 0.01 to 30 parts by weight per 100 parts by weight of the total solid preparation.

The claim does not require a particular dose of either active ingredient. It also does not specify tablet shape, coating, release profile, compression force, particle size, or manufacturing process.

Claim	Scope	Commercial significance
1	Multilayer solid preparation with pioglitazone or a salt in one layer and glimepiride plus Polysorbate 80 in another layer; Polysorbate 80 at 0.01-30 wt%	Broadest independent composition claim
2	Claim 1 limited to pioglitazone hydrochloride	Covers the principal pharmaceutical salt used in commercial pioglitazone products
3	Claim 1 limited to a pioglitazone hydrochloride layer and a glimepiride/Polysorbate 80 layer	Repeats the principal commercial embodiment
4	Claim 1 with Polysorbate 80 at 0.05-20 wt%	Intermediate dependent range
5	Claim 1 with Polysorbate 80 at 0.2-1 wt%	Narrowest and most commercially targeted concentration range

The use of “comprising” makes the claims open-ended. An accused product can contain additional excipients, coatings, binders, disintegrants, lubricants, or active ingredients and still fall within the claim if all required limitations are present.

How should the claims be construed?

What does “layer” require?

“Layer” is a structural limitation. A conventional monolithic tablet in which pioglitazone and glimepiride are distributed throughout the same matrix may avoid the claims if it lacks identifiable separate layers.

A bilayer tablet is the clearest infringement risk. A multilayer tablet with a pioglitazone hydrochloride layer and a separate glimepiride layer also falls within the ordinary technical scope if the glimepiride layer contains Polysorbate 80.

A product may remain within the claims even if:

• The two layers are compressed sequentially.
• One or both layers contain additional active ingredients.
• The tablet has an external film coating.
• The active ingredients are present as granules within their respective layers.
• The formulation uses different excipients from the patented product.

The claim does not expressly require the layers to be physically isolated across the entire tablet. It requires a solid preparation having a layer containing pioglitazone and a layer containing glimepiride and Polysorbate 80.

How is the Polysorbate 80 limitation measured?

The claims measure Polysorbate 80 against the total weight of the solid preparation, not merely against the weight of the glimepiride layer. This creates a quantitative infringement issue.

For example, under claim 5:

[ \text{Polysorbate 80 percentage} = \frac{\text{weight of Polysorbate 80}}{\text{total solid preparation weight}} \times 100 ]

The result must be between 0.2% and 1% by weight, assuming “parts by weight based on 100 parts by weight” is treated as a weight percentage.

A formulation containing 0.5 mg of Polysorbate 80 in a 100 mg tablet would contain 0.5% by weight and fall within claim 5, subject to the other claim elements. The same 0.5 mg amount in a 500 mg tablet would equal 0.1% and would not meet claim 5, although it could fall within claims 1 or 4.

Does the patent cover a single-layer combination tablet?

Not on the face of the asserted claims. Each claim requires a layer containing pioglitazone or its salt and a layer containing glimepiride and Polysorbate 80. A single-layer tablet could avoid literal infringement if the product lacks separate structural layers.

The risk would depend on the physical architecture of the dosage form and on any doctrine-of-equivalents argument. A formulation designed to avoid the patent should not rely solely on labeling the product “single layer.” Manufacturing records, cross-sectional microscopy, granulation structure, and excipient distribution could become relevant in litigation.

What are the strongest and weakest claims?

Claim 1 is the principal enforcement claim because it covers both pioglitazone free form or salt forms and a broad Polysorbate 80 concentration range. Its main vulnerability is the requirement for separate layers and the specific location of Polysorbate 80 in the glimepiride layer.

Claims 2 and 3 are narrower because they require pioglitazone hydrochloride. They are commercially important because pioglitazone hydrochloride is the standard pharmaceutical form in branded and generic pioglitazone products.

Claim 5 is narrower but potentially easier to apply against a commercial product if the patented concentration range corresponds to the product’s actual formulation. Narrow concentration claims often depend on reliable formulation disclosure, analytical testing, and treatment of manufacturing tolerances.

Issue	Claim 1	Claim 5
Pioglitazone form	Pioglitazone or any salt	Same
Dosage architecture	Separate layers required	Same
Glimepiride layer	Required	Required
Polysorbate 80 range	0.01-30 wt%	0.2-1 wt%
Design-around flexibility	Lower because range is broad	Higher because range is narrow
Commercial relevance	Broad platform claim	Targeted formulation claim

When did US Patent 7,700,128 expire?

US Patent 7,700,128 issued on April 20, 2010. Its term is governed by the 20-year patent term applicable to applications claiming priority through the international patent system. The ordinary term associated with the patent family ended in November 2023, subject to any patent-term adjustment recorded by the USPTO.

The practical implications are:

• The patent is no longer an ordinary current barrier to US generic development.
• A Paragraph IV certification directed solely to this patent would generally be unnecessary after expiration.
• The patent can remain relevant to historical litigation, damages analysis, freedom-to-operate reviews, and prosecution strategy.
• Related continuation, divisional, or foreign patents must be checked separately because family members can have different claim scope and expiration dates.

Patent expiration does not eliminate the need to review other Orange Book-listed patents, unlisted formulation patents, regulatory exclusivities, or state-law commercial agreements.

What is the FDA and Orange Book status of the pioglitazone-glimepiride product?

The relevant commercial product is Duetact, a fixed-dose combination of pioglitazone hydrochloride and glimepiride. The product was approved by the FDA under NDA 021925 for adults with type 2 diabetes as an adjunct to diet and exercise.

Duetact is a small-molecule combination product, not a biologic. Biosimilar pathways under the Public Health Service Act do not apply. A competing product would ordinarily proceed through an ANDA or, depending on the product and regulatory strategy, another abbreviated or full NDA pathway.

The regulatory distinction is important:

Regulatory issue	Effect
Active ingredients	Pioglitazone hydrochloride and glimepiride
Product type	Fixed-dose small-molecule combination
FDA pathway	NDA for the reference product; ANDA pathway may be available for a qualifying generic
Biosimilar exposure	None
Orange Book relevance	Patent listing and exclusivity information for the reference NDA
Formulation proof	May require comparative dissolution and pharmaceutical equivalence analysis
Patent challenge	Historically could involve Paragraph IV certification if the patent was listed and unexpired

The Orange Book is the controlling source for current listing status and certifications. A historical patent listing for US 7,700,128 would not itself create present exclusivity after patent expiration.

What Paragraph IV challenges and litigation affect this patent?

A Paragraph IV certification would have been relevant only while the patent was unexpired and listed for the reference product. The patent’s formulation limitations would have created several potential certification positions:

1. The proposed generic does not contain separate pioglitazone and glimepiride layers.
2. Polysorbate 80 is absent.
3. Polysorbate 80 is present outside the glimepiride layer.
4. Polysorbate 80 is below 0.01% or above 30% by weight.
5. The proposed product uses a different pioglitazone salt.
6. The patent is invalid for anticipation, obviousness, indefiniteness, or inadequate written description.
7. The patent is unenforceable based on prosecution conduct or other equitable grounds.

The strongest non-infringement design-around would generally be a single-layer tablet without Polysorbate 80 in a glimepiride-containing layer. A bilayer tablet that uses Polysorbate 80 as a wetting or solubilizing excipient would create a materially greater risk.

No biosimilar litigation is relevant. Any litigation would concern small-molecule patent infringement, Hatch-Waxman procedures, ANDA approval, or commercial manufacturing.

What formulation alternatives avoid the patent?

A generic developer can reduce literal infringement risk through several formulation strategies:

Single-layer formulation

A homogeneous matrix containing both active ingredients would avoid the express two-layer requirement if the product lacks separately identifiable layers.

Separate dosage units

Packaging pioglitazone and glimepiride in separate tablets rather than using one multilayer tablet would avoid the claimed solid preparation if no single solid dosage unit contains both required layers.

Alternative surfactant

Replacing Polysorbate 80 with another excipient, such as a different surfactant or wetting agent, could avoid the Polysorbate 80 limitation. The replacement must be assessed for regulatory equivalence, dissolution performance, and other patents.

Polysorbate 80 outside the glimepiride layer

If Polysorbate 80 is used only in a coating or pioglitazone layer, the product may avoid the claim requirement that the glimepiride-containing layer include Polysorbate 80.

Concentration outside the claimed range

A product below 0.01% or above 30% by total preparation weight would fall outside claim 1’s numerical range. This strategy is unlikely to be commercially attractive at the high end and may affect performance at the low end.

How strong is the patent estate?

The patent had meaningful historical value because it targeted the architecture of a commercial fixed-dose combination rather than merely claiming a broad therapeutic use. Its strengths were:

• Specific coverage of a bilayer solid preparation.
• Coverage of pioglitazone hydrochloride.
• Broad Polysorbate 80 concentration coverage in claim 1.
• Narrower claims directed to likely commercial concentration ranges.
• Open-ended “comprising” language.

Its weaknesses were:

• Dependence on physical layer structure.
• Dependence on Polysorbate 80 being in the glimepiride layer.
• Absence of method-of-use claims in the supplied claims.
• Absence of manufacturing-process claims in the supplied claims.
• Potential design-around through a monolayer formulation, alternative surfactant, or separate dosage units.
• Expiration of the ordinary patent term.

Overall, US 7,700,128 was a targeted formulation patent rather than a broad product monopoly. It could have delayed or complicated approval of a matching bilayer generic, but it did not prevent all pioglitazone-glimepiride combinations.

What other patent categories matter for generic entry?

Method-of-use patents

The supplied claims do not cover treatment of type 2 diabetes, glycemic control, insulin resistance, or a specific patient population. Any method-of-use patents would need separate review in the Orange Book and USPTO records.

Formulation patents

Formulation patents may cover:

• Bilayer or multilayer tablet architecture.
• Enhanced glimepiride dissolution.
• Pioglitazone stability.
• Specific excipient combinations.
• Film coatings.
• Controlled or immediate release.
• Granulation and compression processes.

US 7,700,128 is most relevant to the bilayer and Polysorbate 80 combination.

Manufacturing patents

A competitor can avoid the composition claims while still infringing a separate process patent. Relevant processes could include wet granulation, sequential compression, layer bonding, coating, or control of excipient distribution.

Geographic coverage

US 7,700,128 has effect only in the United States. Foreign counterparts may have existed in jurisdictions including Japan, Europe, and other markets, but foreign claim scope, prosecution history, and expiry dates must be evaluated independently. A US design-around does not establish freedom to operate in Europe, Japan, Canada, or other jurisdictions.

What is the commercial and competitive significance?

Duetact competed in the oral type 2 diabetes market against single-agent pioglitazone, sulfonylureas such as glimepiride, metformin combinations, DPP-4 inhibitors, SGLT2 inhibitors, and GLP-1 therapies.

The patent’s commercial value was constrained by the relatively narrow market for the pioglitazone-glimepiride combination and by the availability of alternative diabetes treatments. Its primary value was defensive: protecting a specific fixed-dose product and complicating development of a closely matching generic.

The patent does not protect:

• Pioglitazone alone.
• Glimepiride alone.
• The therapeutic use of either ingredient.
• All combinations of pioglitazone and glimepiride.
• A monolayer tablet without the claimed Polysorbate 80 arrangement.
• Injectable, liquid, capsule, or transdermal products.

Key Takeaways

• US 7,700,128 covers a multilayer solid preparation containing pioglitazone or a salt in one layer and glimepiride plus Polysorbate 80 in another.
• Pioglitazone hydrochloride is expressly covered by claims 2 and 3.
• Claim 1 covers 0.01% to 30% Polysorbate 80 by total solid-preparation weight.
• Claim 5 targets the narrower 0.2% to 1% range.
• The patent does not broadly cover the active-ingredient combination or a method of treating diabetes.
• A single-layer tablet, separate tablets, alternative surfactant, or Polysorbate 80 outside the glimepiride layer may provide design-around routes.
• The patent’s ordinary US term expired in November 2023, subject to the USPTO’s recorded term adjustment.
• Biosimilar risk is irrelevant because pioglitazone and glimepiride are small molecules.
• Current generic-entry analysis must focus on any unexpired related patents, Orange Book listings, regulatory exclusivity, and manufacturing patents.

FAQs

Does US Patent 7,700,128 cover Duetact by name?

No. It covers structural and compositional features of the dosage form. A product can fall within the claims without being marketed under the Duetact name, and Duetact would not infringe unless its formulation satisfies the claimed limitations.

Can a generic use Polysorbate 80 and avoid the patent?

Potentially. The product would need to avoid the claimed layer arrangement or place Polysorbate 80 outside the glimepiride-containing layer. Concentration and total-tablet weight must also be evaluated.

Does the patent cover pioglitazone sodium or other salts?

Claim 1 reaches pioglitazone “or a salt thereof.” Claims 2 and 3 specifically narrow the product to pioglitazone hydrochloride. A different salt may remain within claim 1.

Is a multilayer tablet automatically infringing?

No. It must contain all required elements, including a pioglitazone-containing layer, a separate glimepiride-containing layer, Polysorbate 80 in the glimepiride layer, and the required concentration range.

Can the expired patent still affect a generic launch?

Yes, indirectly. It may affect historical damages, contractual obligations, prosecution disclosures, technical documentation, and the analysis of related patent-family members. Expiration alone does not establish that every related patent or regulatory barrier has ended.

References

1. U.S. Patent No. 7,700,128. (2010). Pharmaceutical composition containing pioglitazone and glimepiride. United States Patent and Trademark Office.

2. U.S. Food and Drug Administration. (n.d.). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA.

3. U.S. Food and Drug Administration. (2006). Duetact prescribing information. Takeda Pharmaceuticals.

4. United States Code, 35 U.S.C. § 154. (2024). Contents and term of patent; provisional rights.

5. United States Code, 21 U.S.C. § 355. (2024). New drugs.

Drugs Protected by US Patent 7,700,128

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Takeda Pharms Usa	DUETACT	glimepiride; pioglitazone hydrochloride	TABLET;ORAL	021925-001	Jul 28, 2006	AB	RX	Yes	Yes	7,700,128		Y
Takeda Pharms Usa	DUETACT	glimepiride; pioglitazone hydrochloride	TABLET;ORAL	021925-002	Jul 28, 2006	AB	RX	Yes	No	7,700,128		Y

Foreign Priority and PCT Information for Patent: 7,700,128

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Japan	2003-371679	Oct 31, 2003

PCT Information
PCT Filed	October 21, 2004	PCT Application Number:	PCT/JP2004/015958
PCT Publication Date:	May 12, 2005	PCT Publication Number:	WO2005/041962

International Family Members for US Patent 7,700,128

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	046210
Australia	2004285354
Brazil	PI0414979
Canada	2540225
China	1874774
Cyprus	1117176