Methylated Sulfonamide Antibacterial Drug Class List

Drugs in Drug Class: Methylated Sulfonamide Antibacterial

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Rising	SULFAMYLON	mafenide acetate	CREAM;TOPICAL	016763-001	Approved Prior to Jan 1, 1982		RX	Yes	Yes

Last updated: July 26, 2026

rket dynamics and patent landscape for Methylated Sulfonamide antibacterial drugs

The methylated sulfonamide antibacterial class is dominated by legacy, off-patent small molecules (notably the methylated sulfonamide antibacterials used in urinary tract and other bacterial infections). Patent protection in this space typically comes from (1) older composition-of-matter filings that have long since expired in most markets, (2) later, narrower formulation/process patents, and (3) method-of-use or polymorph/crystal form IP where registries and Orange Book listings exist. Competitive dynamics are therefore driven less by entry barriers and more by regulatory exclusivity on specific ANDA products, supply chain economics, and price competition.

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What drugs are in the methylated sulfonamide antibacterial class and where are they sold?

The term “methylated sulfonamide antibacterial” is most commonly used in practice to describe sulfonamides bearing methyl substitution patterns on the sulfonamide scaffold, used as urinary tract and broad bacterial antibacterials. The most commercially relevant members are typically methylated sulfonamide derivatives historically marketed as oral and sometimes compounded/alternative formulations rather than newer, patented branded products.

Common active ingredients to map for market and IP

In commercial and regulatory datasets, methylated sulfonamide antibacterials most often map to:

• Methylsulfamethoxazole-type sulfonamide antibacterials (including methyl-substituted sulfonamide analogs used for UTIs and other bacterial indications)
• Trimethoprim-sulfonamide combinations where the sulfonamide component is a methylated sulfonamide (where the sulfonamide methylation is part of the marketed fixed-dose combination)

Where market activity concentrates

• United States: generics dominate; brand presence depends on remaining exclusivity on specific NDAs/505(b)(2) products.
• EU5 + UK: similar, with national marketing authorizations and local supply dynamics.
• Emerging markets: pricing pressure is high; supply and compliance drive entry more than patent leverage.

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What patents protect methylated sulfonamide antibacterial drugs?

Patent estates for methylated sulfonamide antibacterials are usually concentrated in three buckets:

1. Composition-of-matter (older filings on the sulfonamide core and salts)
2. Formulation and dosage patents (tablet/capsule compositions, stabilizers, film coatings, dissolution targeting)
3. Manufacturing/process patents (crystal formation, purification, drying conditions)

Because these actives are largely mature, the strongest remaining IP in many cases is not composition-of-matter on the molecule, but product-specific IP still listed in regulatory registries for particular strengths, dosage forms, or clinical use wording.

How the estate typically stratifies by patent type

• Core molecule patents: usually expired long ago in the US and major jurisdictions.
• Salt/polymorph/crystal patents: may persist if there were late, isolated form developments.
• Combination/product patents: arise where fixed-dose combinations were developed under newer registrations or involve specific ratios and excipient systems.

Orange Book listings drive the real-time picture

For US markets, the Orange Book is the practical interface between patents and generic launch readiness. In this therapeutic class, most market access is determined by:

• whether an approved generic can launch immediately as an ANDA referencing an eligible reference listed drug
• whether any listed patents still block ANDA approval (and whether a Paragraph IV pathway is available)

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When does methylated sulfonamide antibacterial IP lose exclusivity?

Featured snippet answer

For most methylated sulfonamide antibacterials, composition-of-matter exclusivity has already ended; any remaining exclusivity is typically limited to specific product listings (formulation/process patents or NDA/505(b)(2) exclusivity tied to a particular branded product) rather than class-wide exclusivity.

Typical exclusivity timeline pattern

• Early-to-mid period: molecule patents dominate; fewer generics.
• Later period (current market reality): generic competition drives price; remaining blockers are usually product-specific Orange Book patents.
• Residual runway: formulation, process, and certain method-of-use patents tied to late-lifecycle NDA changes or new dosage forms.

What this means for entry timing

• The market’s “timing lever” is less about hard molecule expiry and more about:
  • whether a specific strength/dosage form still has active listed patents
  • whether a generic manufacturer faces a live infringement case
  • whether regulatory exclusivity (rare in mature actives) blocks ANDA approval for a period

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What Paragraph IV challenges exist for methylated sulfonamide antibacterials?

How Paragraph IV plays out in this class

Paragraph IV filings are most likely where:

• branded reference product still has active Orange Book listed patents for a specific formulation/strength
• generics can certify non-infringement or invalidity while seeking approval before patent expiry
• settlement agreements are used to secure market entry on a schedule

In mature sulfonamide antibacterials, Paragraph IV is less frequent than in specialty on-patent markets but still occurs around specific legacy brand line extensions (new dosage forms, new strength, or 505(b)(2) reformulations).

Market effect

Where Paragraph IV results in:

• a sustained block: delayed ANDA launch and preserved market share
• a successful launch: rapid generic share gains and sharp price erosion
• a settlement: entry date is set by settlement schedule rather than patent expiry alone

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How many patents cover methylated sulfonamide antibacterial products in the Orange Book?

Industry reality

For older antibacterials in this class, the Orange Book patent count per referenced drug commonly skews toward:

• a handful of listed patents on formulation/process and method-of-use
• many expired composition-of-matter patents not listed anymore (or listed but expired)

Practical read-through for business

• If the patent list is short and most claims are formulation/process, litigation risk is usually lower and design-around is more feasible.
• If the patent list includes combination or method-of-use claims, the generic may face higher litigation and settlement probability.

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Which companies are challenging methylated sulfonamide antibacterial patents?

Competitive landscape pattern

Across legacy antibacterials, generic challengers typically come from:

• large multi-product ANDA players with established sulfonamide portfolios
• regionally strong generics that focus on low-margin scale production
• suppliers who can win on logistics, contracts, and procurement channels rather than IP

What to look for in assignments

For actionable mapping, the highest signal comes from:

• assignees that repeatedly appear across older formulation/process patents
• companies that are known to file ANDAs early and manage Paragraph IV strategy across multiple strengths

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What is the Orange Book status of methylated sulfonamide antibacterial brands?

Featured snippet answer

Orange Book status for methylated sulfonamide antibacterials is usually dominated by generic-eligible products, with a small number of still-listed patents on specific drug products.

Why Orange Book status matters more than class membership

Two products with the same active ingredient may have different:

• listed patent families
• dosage forms
• RLD/Reference product eligibility
• remaining listed patents

Market entry risk is therefore product-specific, not molecule-specific.

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What formulations are protected for methylated sulfonamide antibacterials?

Formulation protection in this class typically includes:

• tablet/capsule compositions with particular excipient systems
• coatings that affect dissolution rate and stability
• granulation and compression methods tied to consistent bioavailability
• stabilized suspensions when liquid dosage forms exist

Where design-around is plausible

Design-around tends to be more feasible when:

• patents target excipient systems or processing conditions
• claims do not lock in a specific release profile or dissolution metric with narrow ranges

Where design-around is harder

Design-around is harder when patents define:

• dissolution specifications tied to a protected method or composition parameter
• combination-specific ratios and formulation constraints

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What method-of-use patents exist for methylated sulfonamide antibacterial drugs?

Method-of-use patents in mature antibacterial classes typically aim at:

• specific indications
• dosing regimens
• patient subsets or infection types

Business impact

Method-of-use patents can matter for:

• label wording and exclusivity on specific claims
• “skinny labeling” strategies for generic products
• settlement structure when brands are still leveraging regulatory-defined clinical language

In mature antibacterials, method-of-use patents are less likely to be the primary barrier, but they can still create leverage if they are actively listed.

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What patent litigation affects methylated sulfonamide antibacterial market access?

Common litigation triggers

• generic ANDA approvals blocked by live listed patents
• infringement suits tied to formulation/process differences
• counterclaims of invalidity and non-infringement

Settlement-driven outcomes are typical

For small-molecule mature products:

• litigation often resolves into an agreement with a defined launch date
• the brand’s objective is to secure revenue continuity and manage supply transitions
• the generic’s objective is certainty and a design-around path

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How does FDA regulatory status drive generic entry for methylated sulfonamide antibacterials?

Regulatory pathways

• ANDA (generic): most relevant for this class because actives are mature.
• 505(b)(2): occurs when formulations or dosing require reliance on literature, or where new fixed-dose combinations are developed.
• NDA (brand): usually limited due to maturity, except for line extensions.

Exclusivity versus patents

Even when patents are expired, FDA approval still depends on:

• reference listed drug status and labeling
• whether listed patents are cleared (or certified via Paragraph IV)
• whether any unexpired regulatory exclusivity remains for a specific product

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How do methylated sulfonamide antibacterials compare with other sulfonamides or classic UTIs on patent risk?

Comparative pattern

Against newer antibacterial classes, methylated sulfonamide antibacterials present:

• lower hard-IP risk due to early expirations
• higher operational leverage via manufacturing cost, quality systems, and supply stability
• lower reformulation opportunity, because the class is already generic-dense

Competitive implications

• Brand leverage is often exhausted; pricing power usually rests with contracting and supply rather than exclusivity.
• Generic market entry can be fast if no live patents remain and bioequivalence is straightforward.

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Key market dynamics: why pricing and supply dominate more than IP

Demand drivers

• chronic UTI treatment cycles
• antimicrobial stewardship-driven usage patterns
• procurement consolidation at distributors and hospital systems

Supply and cost drivers

• manufacturing scale and chemical supply continuity
• API sourcing risk and regulatory compliance
• pricing pressure from multi-generic formularies

How the patent landscape affects commercial strategy

• where patents are expired: focus shifts to low-cost production and contracting
• where formulation/process patents remain: focus shifts to Paragraph IV and settlement timing rather than long-term brand defensibility

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Key risks for generic entry and what typically blocks launches

Primary launch blockers in this class

1. Active listed Orange Book patents for the specific strength/dosage form
2. Live infringement litigation following Paragraph IV certification
3. Settlement agreements that delay entry regardless of patent expiry date
4. Manufacturing changes that are not covered by existing bioequivalence pathways

Typical mitigation strategies used by generics

• early ANDA submission planning around patent expiry
• procedural handling of the “listed patent” landscape by strength
• formulation/process alignment to bioequivalence requirements while reducing infringement exposure

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Key Takeaways

• Methylated sulfonamide antibacterials are structurally mature; composition-of-matter IP is generally not the main driver of market barriers.
• Remaining protection is typically product-specific: formulation, process, combination specifics, and occasional method-of-use language.
• Generic entry timing is mostly determined by Orange Book listed patents and regulatory certifications, not by class-wide exclusivity.
• Market share outcomes tend to be driven by price competition and supply chain economics, with litigation and settlements used to manage timing when specific listed patents remain active.

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FAQs

1) What typically remains patent-relevant for methylated sulfonamide antibacterials after composition patents expire?
Formulation/process and sometimes method-of-use claims that are still listed for specific strengths and dosage forms in regulatory registries.

2) How do Paragraph IV filings affect methylated sulfonamide antibacterial pricing?
They can accelerate generic approvals and create rapid price erosion when a launch is not blocked by live patents or settlement terms.

3) Does Orange Book status differ by strength or dosage form for the same methylated sulfonamide active ingredient?
Yes. Patent listings and certifications are product-specific, so risk and timing can vary by strength and formulation.

4) Are combination products (methylated sulfonamide plus another agent) more patent-sensitive than single-ingredient products?
Often, yes, because combination ratio and formulation constraints can support additional patent families and Orange Book listings.

5) What is the most common reason a generic methylated sulfonamide antibacterial launch is delayed?
A live listed patent for the specific RLD product and strength, leading to litigation or a settlement-imposed entry date.

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References

No sources were cited.