Scope and Claims Analysis for US Patent 5,859,037: Synergistic Sulfonylurea + Glitazone Fixed Combinations for Type 2 Diabetes

US Patent 5,859,037 (United States) claims a narrow but flexible fixed-dose and method-of-use concept: oral antidiabetic combination products that pair a sulfonylurea in a specified mg range with a “glitazone” (thiazolidinedione class) in a specified mg range, where the two agents are characterized as “synergistic” for treating non-insulin dependent diabetes mellitus (NIDDM), i.e., Type 2 diabetes.

This is an early combination-entry patent strategy: it does not claim a chemical synthesis route. It claims (1) the combination composition defined by dosage ranges and “synergy” for NIDDM, and (2) treating methods that administer those ranges. Dependent claims then narrow the genus to named drug members (with a final example pairing glyburide + troglitazone).

What does US 5,859,037 claim, and how broad is the “composition” scope?

Direct answer: The independent claims cover compositions and treatment methods for NIDDM using a sulfonylurea amount of ~3 mg to ~250 mg combined with a glitazone amount of ~100 mg to ~1,000 mg, where the amounts are “synergistic.”

Claim architecture: one independent concept, multiple narrowing dependent claims

US 5,859,037 has eight claims based on two claim families:

Composition family
- Claim 1: Composition comprising specified dose ranges of a sulfonylurea + a glitazone, with synergy for NIDDM in humans.
- Claims 2-4: Narrow the sulfonylurea and glitazone selections, ending with a specific combination (troglitazone and glyburide).
Method family
- Claim 5: Method of treating NIDDM by administering to a patient sulfonylurea (3–250 mg) + glitazone (100–1,000 mg), where synergy is present.
- Claims 6-8: Narrow the selections to enumerated agents; Claim 8 ends with glyburide + troglitazone.

Key scope drivers in Claim 1

Claim 1’s scope is controlled by five elements that must all be satisfied:

Drug class requirement: sulfonylurea antidiabetic agent + glitazone antidiabetic agent.
Dose range for sulfonylurea: “about 3 mg” to “about 250 mg.”
Dose range for glitazone: “about 100 mg” to “about 1,000 mg.”
Patient population: humans with NIDDM.
Functional characterization: “said amounts of sulfonylurea and glitazone being synergistic for the treatment of non-insulin dependent diabetes mellitus.”

The “synergistic” element is the most litigation-relevant because it converts a straightforward dose combination claim into a performance-based requirement. Practically, it pushes the infringement analysis toward whether the accused product or regimen is marketed/used with dosage amounts that achieve synergy as contemplated by the patent.

How “fixed combination” is the claim in practice?

The independent claims say “A composition comprising … sulfonylurea … and … glitazone” (composition claim) and “administering … in combination” (method claim). That language typically targets:

a single formulation containing both agents, for Claim 1, and
a coordinated dosing regimen of both agents, for Claim 5, even if formulated separately, because the method is about what is administered “in combination” and within defined dose ranges.

What patents protect synergistic sulfonylurea + glitazone combinations like glyburide/troglitazone?

Direct answer: US 5,859,037 protects synergy-based combination compositions and methods using specified dose ranges, with dependent claims specifically naming sulfonylureas (including glyburide) and glitazones (including troglitazone).

Dependent claims narrow to named drug members, creating multiple “avenues” to infringement

Dependent claim mapping from your text:

Sulfonylurea enumerations

Claim 2 (composition) lists: glisoxepid, glyburide, acetohexamide, chlorpropamide, glibornuride, tolbutamide, tolazamide, glipizide, gliclazide, gliquidone, glyhexamide, phenbutamide, tolcyclamide.
Claim 6 (method) lists essentially the same set with two naming differences you provided: it includes “gliclozide” and “phenbentamide” (which appear to be variant spellings for gliclazide and phenbutamide in many patent datasets).

Glitazone enumerations

Claim 3 (composition) lists: troglitazone, ciglitazone, pioglitazone, englitazone, TA 174, BRL 49653.
Claim 7 (method) lists the same set.

Specific end-point combination

Claim 4 (composition): troglitazone + glyburide.
Claim 8 (method): glyburide + troglitazone.

Practical “coverage” implication

Because Claim 1 is a genus over the dose ranges and two classes, infringement risk is not limited to glyburide/troglitazone. The dependent claims demonstrate the intended embodiment set, but the independent claims still read on any sulfonylurea within 3–250 mg and any glitazone within 100–1,000 mg so long as the “synergistic” characteristic is met.

What is the effective infringement test for the “synergistic” limitation in US 5,859,037?

Direct answer: The claim requires both prescribed dose ranges and a synergy characterization for NIDDM treatment; a viable infringement analysis typically hinges on whether the accused combination at the relevant doses is supported by comparative efficacy showing synergy rather than additive or merely combined effect.

Why synergy matters in claim scope

If a defendant argues the combination is only additive or expected based on class pharmacology, the “synergistic” limitation creates a fact issue tied to:

efficacy data used to define synergy,
the specific dose amounts administered in the accused product/regimen,
clinical relevance to NIDDM (Type 2) and humans.

How this affects noninfringement defenses

Design-around strategies often focus on one of three claim elements:

Dose range avoidance: use sulfonylurea outside 3–250 mg or glitazone outside 100–1,000 mg.
Class member avoidance: use a non-glitazone partner or a sulfonylurea not covered (though Claim 1 is broad over sulfonylureas).
Synergy challenge: show lack of synergy at the claimed dose pairing in humans, or characterize the effect as non-synergistic.

How do the dosage ranges constrain claim interpretation?

Direct answer: The independent claims set numeric “about” ranges that likely drive both infringement and validity arguments. Sulfonylurea: ~3–250 mg. Glitazone: ~100–1,000 mg.

Dose range elements

Sulfonylurea: 3–250 mg “about”
Glitazone: 100–1,000 mg “about”

Why these numbers are commercially meaningful

They are broad enough to cover multiple marketed dosing levels across the sulfonylurea and thiazolidinedione class, but narrow enough to exclude:

very low sulfonylurea titrations below ~3 mg, and
very low glitazone doses below ~100 mg.

On the higher end, they exclude:

very high glitazone doses above ~1,000 mg, and
very high sulfonylurea doses above ~250 mg.

Which drug pair is the tightest target: glyburide + troglitazone?

Direct answer: The tightest protection is in dependent Claims 4 and 8, which expressly require troglitazone with glyburide (for composition and method, respectively).

Claim 4: composition specificity

To infringe Claim 4 (composition), an accused product must be a composition “comprising” both:

troglitazone, and
glyburide, and still satisfy the structural dose-range and synergy framing from Claim 1/3/2, as incorporated by dependency.

Claim 8: method specificity

To infringe Claim 8 (method), an accused regimen must administer:

glyburide and
troglitazone, for NIDDM in humans, within the synergistic dose ranges.

What is the likely patent estate breadth beyond this single US patent?

Direct answer: Based on the claim scope you provided, US 5,859,037 appears to be a formulation-and-method combination patent centered on a synergy claim. Its practical competitive relevance is in combination products using oral sulfonylureas with thiazolidinediones.

How the estate typically clusters for this type of concept

While your prompt gives only claim text, the structure (class pairing + synergy + dose ranges + enumerated examples) is consistent with a common family strategy:

one independent broad genus claim,
dependent claims naming drug members,
and a method claim mirroring the composition dose definition.

In litigation, such patents are usually asserted against:

fixed-dose combination products, if any,
or combination regimens sold or promoted as “synergistic” for Type 2 diabetes at specific doses.

What Orange Book status or FDA regulatory posture applies to US 5,859,037?

Direct answer: The question cannot be answered from the provided information. US 5,859,037 is a patent number, but no drug product name(s), application numbers, or Orange Book listings are included in your prompt.

(Per constraints, only complete answers are produced when the necessary linked FDA product/patent linkage data is available in the input. It is not.)

How strong is the enforceability of US 5,859,037 given the claim language?

Direct answer: Strength is driven by the “synergistic” limitation and by whether the specification supports a clear, reproducible synergy definition for the claimed dose ranges. Enforceability also depends on how strictly a court requires proof of synergy tied to the exact dose pairing.

Strength factors implied by the claim set

Positive factor: The claims are not limited to one molecule pair. They cover many sulfonylureas and many glitazones.
Negative factor: “Synergistic” creates an evidentiary burden. Without a strong, specific synergy showing tied to the claimed ranges, a court could narrow interpretation or find noninfringement.

Validity exposure typically arises from:

whether synergy is an inherent property of known class combinations,
whether the claimed ranges were routine optimization,
whether the claim reads on known combinations without a truly novel synergy demonstration.

(Specific grounds cannot be mapped to exact prior art patents without the application’s bibliographic data and cited references.)

How would a generic or biosimilar entry risk be assessed for this patent?

Direct answer: The risk is highest for generics that launch a sulfonylurea + glitazone combination product or prescribe dosing regimens that fall within the claimed dose ranges and are characterized as synergistic for NIDDM.

Generic entry scenarios likely within claim scope

A fixed-dose product containing, for example:
- glyburide + troglitazone at doses mapping into 3–250 mg and 100–1,000 mg ranges; and
- marketed and used as synergistic for Type 2 diabetes.
A co-administered regimen in which the prescriber uses both drugs in the claimed dose ranges “in combination” with synergy framing.

Entry scenarios likely outside claim scope

If a product’s dosing falls outside the glitazone range (<100 mg “about”) or sulfonylurea range (<3 mg “about”).
If the regimen uses a non-glitazone partner, or if synergy cannot be established for the claimed dose pairing in humans.

Comparison: how does the claim scope differ between the independent genus (Claim 1/5) and the narrowed exemplars (Claim 4/8)?

Claim	Scope type	Key requirement	Practical coverage
Claim 1	Composition genus	Sulfonylurea 3–250 mg + glitazone 100–1,000 mg, synergistic for NIDDM	Broadest composition coverage across multiple class members
Claim 4	Composition exemplar	Troglitazone + glyburide (and includes genus limitations by dependency)	Narrowest composition coverage
Claim 5	Method genus	Administer sulfonylurea 3–250 mg + glitazone 100–1,000 mg, synergistic for NIDDM	Broadest treatment-regimen coverage
Claim 8	Method exemplar	Glyburide + troglitazone (and includes genus limitations by dependency)	Narrowest method coverage

Key Takeaways

US 5,859,037 protects synergistic oral combinations of a sulfonylurea and a glitazone for Type 2 diabetes, defined by dose ranges: sulfonylurea ~3–250 mg and glitazone ~100–1,000 mg.
The claims include both composition and method of treatment formats; infringement analysis must address both dosage compliance and the “synergistic” functional requirement.
Dependent claims add member lists of specific sulfonylureas and glitazones, capped by troglitazone + glyburide in Claims 4 and 8.
Commercial enforcement risk concentrates on products or regimens that replicate the claimed dose ranges and can be supported as synergistic for NIDDM in humans.

FAQs

1) Does US 5,859,037 require a single fixed-dose pill for infringement?
Claim 1 says “composition comprising,” which targets a combined composition, while Claim 5 covers administering “in combination.” The method claim can be implicated by combination regimens meeting the dose-range and synergy requirements.

2) What dose must an accused regimen use to fall within US 5,859,037?
The patent requires sulfonylurea amounts of about 3–250 mg and glitazone amounts of about 100–1,000 mg.

3) Which specific drug pair is explicitly claimed as a dependent embodiment?
The explicitly enumerated combination is glyburide with troglitazone (Claims 4 and 8).

4) Can a manufacturer avoid infringement by using a different glitazone?
If the partner remains a glitazone within the claim’s class concept, dose and synergy still matter. Avoidance would typically require using a non-listed class member or dosing outside the ranges, depending on claim construction.

5) What is the most litigated claim element in this patent?
The functional limitation that the sulfonylurea and glitazone amounts are “synergistic” for treating NIDDM is the pivot for both infringement proof and potential validity challenges.

References

US Patent 5,859,037.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	011829	⤷ Start Trial
Argentina	020973	⤷ Start Trial
Austria	293980	⤷ Start Trial
Australia	5347399	⤷ Start Trial
Australia	5590898	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,859,037

Summary for Patent: 5,859,037