QUINIDEX Drug Patent Profile

Which patents cover Quinidex, and when can generic versions of Quinidex launch?

Quinidex is a drug marketed by Wyeth Pharms Inc and is included in one NDA.

The generic ingredient in QUINIDEX is quinidine sulfate. There are twenty-seven drug master file entries for this compound. One supplier is listed for this compound. Additional details are available on the quinidine sulfate profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Quinidex

A generic version of QUINIDEX was approved as quinidine sulfate by EPIC PHARMA LLC on September 26^th, 1983.

Summary for QUINIDEX

US Patents:	0
Applicants:	1
NDAs:	1

US Patents and Regulatory Information for QUINIDEX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Wyeth Pharms Inc	QUINIDEX	quinidine sulfate	TABLET, EXTENDED RELEASE;ORAL	012796-002	Approved Prior to Jan 1, 1982		DISCN	No	No

QUINIDEX (quinidine gluconate) investment and patent-life fundamentals: Orange Book status, exclusivity timeline, generic/IV competing risk, and revenue sensitivity

Last updated: July 10, 2026

Executive summary

• QUINIDEX is an oral quinidine gluconate product used for rhythm control in atrial and ventricular arrhythmias. Its investment profile is driven primarily by (1) U.S. FDA approval history and Orange Book-listed patents, (2) whether any unexpired formulation, polymorph, or method-of-use patents remain, and (3) practical manufacturing/IP barriers for generic quinidine gluconate.
• In the U.S., quinidine salts and quinidine formulations are an older therapy area. The dominant economics are typically generic-driven once approvals mature, with limited pricing power unless a specific delivery form or dosing-regimen patent is still enforceable.
• A complete, actionable investment and patent-life model for QUINIDEX requires current Orange Book patent listings, patent expiration and exclusivity periods, and documented Paragraph IV litigation or settlements. Those specific, drug-level data are not available in the prompt.

What is QUINIDEX (quinidine gluconate) and how does it generate revenue?

QUINIDEX is marketed as an oral quinidine gluconate therapy. Revenue fundamentals for older antiarrhythmics typically follow a pattern: high dependence on generic availability, stable-to-declining unit volumes as guideline practice shifts, and margin pressure from multiple equivalent competitors.

Key commercial drivers investors model

• Treatment mix by arrhythmia indication (atrial vs ventricular rhythm control) and patient characteristics that determine switching to alternative rhythm control options.
• Generic penetration and pricing versus branded equivalents.
• Prescriber comfort with quinidine tolerability (notably GI and conduction effects) and monitoring practices, which affect adherence and dose persistence.
• Coverage and formulary placement, especially under Medicare Part D and commercial managed care.

What changes the margin profile

• If QUINIDEX has any U.S.-listed, still-enforced patents tied to release characteristics, dissolution behavior, salt form, or dosing regimen, branded-like pricing can persist longer.
• Absent enforceable IP, pricing tends to compress quickly after generic entry through comparative bioequivalence pathways.

What patents protect QUINIDEX in the U.S.?

Direct answer: Patent coverage for QUINIDEX in the U.S. must be verified in the FDA Orange Book for the specific NDC(s) and dosage form(s) tied to “QUINIDEX” branding. The prompt does not include the Orange Book listing details needed to enumerate patent numbers, assignees, expiration dates, and claims scope.

Patent estate categories typically relevant to quinidine salts

For oral antiarrhythmic products, investor diligence usually breaks down patent filings into:

• Composition-of-matter for the active salt (quinidine gluconate) and hydrates/solvates
• Formulation patents: granulation, excipients, coating, dissolution rate modifiers
• Manufacturing process patents: dry granulation steps, milling parameters, mixing order, moisture control
• Method-of-use patents: specific arrhythmia types, dosing schedules, patient subpopulations, monitoring protocols
• Pediatric or orphan exclusivity-related barriers (less common for older oral cardiovascular drugs)

Where to focus claim-scope diligence

• Whether the listed claims are limited to a specific release profile or dissolution specification.
• Whether any claims cover a dosing regimen or patient selection that generic labeling may not be able to match without infringement.

When does QUINIDEX lose exclusivity in the U.S.?

Direct answer: The exclusivity timeline is determined by FDA exclusivity (if applicable) and by the Orange Book patent expiration dates for the specific QUINIDEX NDC(s). Those dates are not provided in the prompt.

How investors quantify exclusivity to launch windows

A standard market-access model uses:

• Earliest Orange Book patent expiration (EOB Exp)
• Any pediatric exclusivity extension (+6 months)
• Any additional U.S. regulatory exclusivity (where applicable)
• Practical barriers from formulation/manufacturing patents even after MME (marketing exclusivity) ends

What Orange Book status does QUINIDEX have for its NDCs?

Direct answer: Orange Book status requires the actual Orange Book entries (listed drug, dosage form, route, active ingredient, NDC strength, and all listed patents with expiration and exclusivity type). The prompt does not contain those Orange Book identifiers.

Are there Paragraph IV generic challenges for QUINIDEX?

Direct answer: Whether any ANDA filers challenged QUINIDEX via Paragraph IV depends on published FDA ANDA litigation records and court filings referencing QUINIDEX and the Orange Book patents. The prompt provides no litigation identifiers, case numbers, or patent lists, so the launch-risk assessment cannot be produced.

What to check in litigation risk scoring

• Whether the challenge attacked formulation patents (harder to design around) versus composition-of-matter.
• Whether a settlement triggers a delayed launch date tied to specific patents.
• Whether exclusivity was invoked in settlement.
• Whether there are ongoing injunction or appeal dynamics.

How strong is the patent estate for QUINIDEX versus generic quinidine gluconate?

Direct answer: Patent strength is assessed by comparing claim scope to design-around feasibility, which requires the Orange Book patent list (numbers, claim types, assignees, and expiration dates). The prompt does not include those.

Investor scoring framework (what the final model would compute)

• Patent count by category (composition/formulation/method-of-use)
• Remaining term by category (months/years to expiration)
• Claim breadth and overlap with typical generic formulations
• Likelihood of invalidity based on prior art common to salt-formulation platforms
• Litigation history (if any) and settlement terms

What formulations of quinidine are legally comparable to QUINIDEX?

QUINIDEX is a brand label for quinidine gluconate. Comparable products in the market can include other quinidine salts or different dosing formats, such as:

• Quinidine sulfate tablets
• Quinidine gluconate in alternative strengths or release formats
• Historical liquid or extended release variants, where available

Investment implication: even if the active moiety is the same, the IP and regulatory pathway can differ by dosage form and release profile. Generic interchangeability is label- and bioequivalence-dependent, not solely active-ingredient dependent.

How does QUINIDEX compare with competing antiarrhythmics on investment fundamentals?

For rhythm control, competitors often include:

• Amiodarone products (including multiple generics post-brand timeline)
• Sotalol formulations
• Dofetilide and other class alternatives
• Newer rhythm control strategies, where guideline shifts can compress demand for older antiarrhythmics

Fundamental comparison factors investors typically normalize across:

• Branded-to-generic transition status
• Ongoing patent thicket intensity
• Administrative barriers (distribution, monitoring requirements, risk management programs)
• Net revenue durability based on guideline positioning

Without QUINIDEX-specific patent and pricing data, the comparative investment conclusion cannot be completed.

What is the FDA regulatory status of QUINIDEX (approval pathway, labeling, and bioequivalence risk)?

Direct answer: Regulatory status details require the FDA approval history for QUINIDEX, including original approval year, any supplements affecting formulation, and the current label strengths. The prompt does not provide FDA regulatory metadata.

What matters for generic entry risk

• Whether QUINIDEX is referenced by current ANDAs under a single listed drug with defined strengths.
• Whether any narrow therapeutic index dosing requires strict release/dissolution matching.
• Whether label changes constrain generic substitution.

What generic entry risks exist for QUINIDEX if patents expire soon?

Direct answer: Generic entry risk depends on which patents are Orange Book-listed and their expiration dates for QUINIDEX’s specific NDC(s). The prompt provides no patent list or expiries, so a launch-timing scenario cannot be calculated.

Typical decision tree investors use

• If Orange Book patents are all expired and no exclusivity remains: high probability of generic competitive entry.
• If patents remain but are easy to design around: risk is moderate, with potential “at-risk” launches for certain ANDA routes.
• If patents are hard to design around (formulation release/dissolution): lower likelihood of early generic substitution.

Which companies are likely to manufacture or challenge QUINIDEX?

Direct answer: Identifying likely manufacturers or challengers requires Orange Book ANDA cross-references and litigation dockets tied to QUINIDEX. The prompt does not include those.

Investment scenarios: base case, upside, and downside

A complete investment scenario model must tie to:

1. remaining patent and exclusivity dates,
2. expected time to generic entries,
3. pricing erosion curve and volume decline assumptions, and
4. regulatory outcomes (if any new formulation/line extensions exist).

The prompt does not include:

• QUINIDEX current revenue or unit volume base,
• payer mix and ASP/MVC benchmarks,
• Orange Book patent list with expiries,
• any known litigation or settlement.

Because those inputs are necessary to produce a complete and accurate investment scenario, no scenario with actionable numeric outcomes can be delivered.

Key Takeaways

• QUINIDEX’s investment fundamentals are determined by Orange Book patent and exclusivity status by NDC, plus the presence or absence of Paragraph IV litigation and settlements.
• Generic-entry economics typically dominate after the last enforceable formulation or method-of-use patent expires.
• A defensible base/upside/downside scenario requires a drug-level Orange Book patent table, expiration timeline, and litigation record tied to QUINIDEX’s exact listed drug entries. Those data are not present in the prompt.

FAQs

1. How do Orange Book patents on quinidine gluconate determine generic launch timing?
2. What is the difference between patent expiration and exclusivity for older cardiovascular brands like QUINIDEX?
3. Which claim types (formulation vs method-of-use) most often block quinidine generic design-around?
4. How does bioequivalence risk affect approval and substitutability of generic quinidine gluconate?
5. What litigation and settlement terms typically delay ANDA entry for oral antiarrhythmics?

References

No sources were cited because the prompt did not include QUINIDEX Orange Book entries, FDA approval history, or litigation records needed to support drug-specific claims.