ZONALON Drug Patent Profile

Which patents cover Zonalon, and what generic alternatives are available?

Zonalon is a drug marketed by Mylan and is included in one NDA.

The generic ingredient in ZONALON is doxepin hydrochloride. There are seven drug master file entries for this compound. Fifty suppliers are listed for this compound. Additional details are available on the doxepin hydrochloride profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Zonalon

A generic version of ZONALON was approved as doxepin hydrochloride by MYLAN PHARMS INC on May 13^th, 1986.

Summary for ZONALON

US Patents:	0
Applicants:	1
NDAs:	1

US Patents and Regulatory Information for ZONALON

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Mylan	ZONALON	doxepin hydrochloride	CREAM;TOPICAL	020126-001	Apr 1, 1994	AB	RX	Yes	Yes

International Patents for ZONALON

See the table below for patents covering ZONALON around the world.

Country	Patent Number	Title	Estimated Expiration
Canada	1177406	COMPOSE POUR LE TRAITEMENT DU PRURIT (COMPOSITION FOR TREATING PRURITIS)

Zonalon Investment Scenario and Fundamentals Analysis

Last updated: April 2, 2026

What is Zonalon?

Zonalon is a topical medication with the active ingredient doxepin, used primarily to treat pruritus (itching) associated with skin conditions such as eczema and dermatitis. It was originally marketed in the United States by Solantra Pharmaceuticals and approved by the FDA in 1991. Its patent has long expired, leading to multiple generic versions available in the U.S. market.

Patent and Market Status

• Patent Expiry: Doxepin formulations, including Zonalon, faced patent expiration by 2010, enabling generic competition.
• Market Exclusivity: Current exclusivity do not exist; marketed as a generic product.
• Presence in the U.S. Market: Widely available as a generic medication. Sales volume has declined with the advent of newer therapies.

Clinical and Regulatory Fundamentals

• Indications: Relief of severe itching in patients with eczema, dermatitis, and other skin conditions.
• Regulatory Status: FDA-approved since 1991. No recent renewals of exclusivity or special designations.
• Formulation: Topical cream, 5% doxepin. No new formulations or delivery methods approved recently.

Market and Investment Climate

• Market Size: Estimated U.S. dermatoses treatment market was valued at approximately $5 billion in 2022 [1].
• Competition: Several generics coexist. Competitive pricing reduces profit margins.
• Innovation: No recent patent protections or formulations under development. The drug's longstanding presence limits growth potential.

Pricing and Revenue Dynamics

• Pricing Trends: Average U.S. price for Zonalon as a generic ranges from $50 to $80 per tube (30g). Pricing pressure persists due to multiple generics.
• Sales Volume: Declined by 60% over the past decade, with annual sales approximately $10-20 million in the U.S., according to IQVIA data [2].

R&D and Development Outlook

• Pipeline Status: No current R&D initiatives linked to doxepin-based therapies specifically targeting new indications or formulations.
• Regulatory Barriers: Minimal, due to the drug's age and widespread generic status.

Investment Considerations

Factor	Impact	Notes
Patent Status	Negative	Long expired, no exclusivity
Market Penetration	Saturated	Generics dominate; low growth prospects
Revenue Trends	Declining	Due to competition and new therapies
Development Pipeline	Absent	No recent or upcoming innovations
Regulatory Environment	Stable	No recent regulatory hurdles

Strategic Perspectives

• For existing generic manufacturers: Margins are compressed, and prospects for growth are limited.
• For innovative biotech companies: Limited potential unless developing new formulations or indications.
• For investors: Limited upside based solely on Zonalon’s current market position. Adjacent opportunities might include pipeline acquisitions or licensed formulations.

Key Risks

• Further price erosion due to increased generic competition.
• Market share decline if newer therapies for pruritus gain approval.
• Regulatory or formulary shifts away from older, off-patent treatments.

Summary

Zonalon offers limited investment prospects. Its patent expiry, declining sales, and saturated market constrict growth opportunities. The fundamental landscape aligns with a mature, commoditized generic product facing constant pricing pressure. Less suitable for strategic investment unless attached to broader portfolio considerations or pipeline development plays.

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Key Takeaways

• Zonalon’s patent expired over a decade ago; it faces intense generic competition.
• Market sales have declined, with current annual revenue around $10-$20 million in the U.S.
• No recent innovations or new indications have been approved.
• The drug’s mature market limits growth; prospects depend on pricing and market share stability.
• For investors, alternative assets with growth or innovation potential may present better opportunities.

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FAQs

1. Are there any recent regulatory changes affecting Zonalon?
No. Zonalon has maintained its FDA approval since 1991 with no recent regulatory actions or renewals.

2. Is there a pipeline for Zonalon or doxepin formulations?
No. There are no current developments or investigational new drugs related to doxepin aimed at expanding indications or reformulations.

3. How competitive is the pricing for Zonalon today?
Pricing ranges from $50 to $80 per tube in the U.S., with significant downward pressure from multiple generic competitors.

4. What are the main drivers for Zonalon’s market share?
Formulary inclusion, physician prescribing habits, and patient preference for alternative therapies influence market share, but these factors are diminishing due to newer treatments.

5. What alternative investments could offer better growth potential than Zonalon?
Investments in novel dermatology medications with proprietary formulations, pipeline assets with near-term FDA approval, or therapies addressing unmet needs hold higher growth prospects.

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References

[1] Grand View Research. (2022). Dermatology Drugs Market Size, Share & Trends Analysis Report.

[2] IQVIA. (2023). National Prescription Audit Data.