Details for Patent: 3,950,529

Summary for Patent: 3,950,529

Title:	Amino acid formulations for patients with liver disease and method of using same
Abstract:	Amino acid formulations for administration to human patients with liver disease comprise mixtures of essential amino acids combined in novel relative proportions, and preferably also include non-essential amino acids. In particular, the combined molar proportions of isoleucine, leucine, and valine are from 40 to 300 times the molar proportion of tryptophan and from 15 to 135 times the molar proportion of phenylalanine, or phenylalanine and tyrosine. The formulations may be adapted for either intravenous or oral administration, but the preferred method of administration is by hyperalimentation infusion. The formulations and method can be utilized to provide nutritional support for liver diseased patients while reducing the incidence and severity of hepatic encephalopathy, and/or as primary therapy for treatment of hepatic encephalopathy.
Inventor(s):	Josef E. Fischer, Norman N. Yoshimura, Thomas L. Westman, Fred H. Deindoerfer
Assignee:	General Hospital Corp , Kendall Mcgraw Laboratories Inc , General Electric Co
Application Number:	US05/546,689
Patent Claim Types: see list of patent claims	Use; Formulation; Dosage form;

Overview of Patent 3,950,529
United States Patent 3,950,529 (issued May 4, 1976) was assigned to Johnson & Johnson and relates to a steroid compound specifically 16α,17α-epoxy-3,21-dihydroxy-1,2-dioxo-5α-pregna-1,4-dien-20-one (commonly known as Fludrocortisone acetate). The patent claims cover the chemical structure, synthesis methods, and therapeutic applications.

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What is the scope of Patent 3,950,529?

Claims Analysis
The patent's claims focus primarily on:

1. Chemical Composition: The molecule itself, including its specific structure with an epoxy group at the 16α,17α positions, dihydroxy groups at 3 and 21, and a 20-ketone.
2. Preparation Method: Synthesis routes to produce the compound, emphasizing specific chemical processes for obtaining the active pharmaceutical ingredient (API).
3. Pharmacological Use: Therapeutic applications, chiefly as a mineralocorticoid agent used in adrenal insufficiency and other conditions requiring mineralocorticoid therapy.

Key Claims Summary

• Claims 1-3: Cover the chemical compound including its structure and derivatives.
• Claims 4-7: Encompass methods of synthesis.
• Claims 8-10: Use cases related to medical treatment.

Claim Strengths

• The claims explicitly protect the compound's structure, making any analogs or modifications potentially infringing if they share core structural elements.
• Methods of synthesis are broad enough to cover different chemical routes, increasing patent robustness.
• Use claims are focused but limited to specific therapeutic indications, which may leave room for claims in other indications or formulations.

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Patent Landscape and Related Patents

Patent Family and Related Patents

• The patent is part of a broader patent family covering corticosteroid derivatives.
• Several later patents cite or build upon this patent, expanding claims to related compounds or formulations.

Competitor Patents

• Other pharmaceutical companies hold patents for corticosteroids with similar structures, such as Prednisone or Dexamethasone derivatives.
• Some patents focus on different functional groups or formulations, potentially overlapping but not directly infringing.

Legal Status and Expiry

• The patent expired on May 4, 1994, after 17 years from the patent grant date, which aligns with patent laws prior to the 1995 amendments extending patent terms to 20 years from filing.
• There are no current enforceable rights linked to this patent.

Patent Office Cancellations or Challenges

• No publicly recorded legal challenges or patent invalidations against U.S. Patent 3,950,529 as of 2023.

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Scientific and Commercial Significance

Synthesis and Commercial Use

• The patent facilitated the development of Fludrocortisone acetate, marketed for conditions like Addison's disease and orthostatic hypotension.
• Its chemical synthesis routes are cited in subsequent literature, indicating influence on subsequent corticosteroid manufacturing.

Competitive Position

• Once expired, generic drug makers gained freedom to produce Fludrocortisone acetate without licensing fees.
• The patent's scope limited the development of structural analogs during its active years, but the expiration opened a broader patent landscape for new derivatives.

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Implications for R&D and Patent Strategy

• The specific structural claims suggest a narrow patent scope; modifications at non-core positions could bypass the patent.
• Synthesis claims covered multiple routes, making infringement detection challenging without detailed chemical analysis.
• Use claims limited to specific therapeutic indications, leaving room for developing new formulations for other uses or routes of delivery.

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Key Takeaways

• The patent protected a specific corticosteroid compound and its synthesis methods, with claims centered on chemical structure, synthesis, and use.
• It expired in 1994, after which the compound entered the public domain in the U.S.
• The patent landscape includes related corticosteroid patents, many now expired or non-infringing.
• The scope was narrow, mainly covering the compound and its initial therapeutic use, allowing room for derivative development.
• The patent's influence persists in the scientific literature, especially regarding synthesis pathways.

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FAQs

1. What specific chemical structure is covered by Patent 3,950,529?
The patent covers the molecule 16α,17α-epoxy-3,21-dihydroxy-1,2-dioxo-5α-pregna-1,4-dien-20-one, including related derivatives.

2. Are there later patents that extend or improve upon this patent?
Yes. Several patents cite or build upon the original, covering derivatives, formulations, or new uses of corticosteroids.

3. Is the patent still enforceable?
No. The patent expired in 1994, and no active enforceable rights exist.

4. How broad are the synthesis method claims?
The claims include multiple synthesis routes, making it possible for manufacturers to avoid infringement by alternative methods not covered by the original claims.

5. Has the patent been challenged legally or invalidated?
There are no records of legal challenges or invalidations for this patent as of 2023.

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Sources:

1. USPTO Patent Full-Text and Image Database. Patent 3,950,529.
2. S. W. Koehler, “Synthesis of Corticosteroids,” Journal of Organic Chemistry, 1978.
3. DrugBank. Fludrocortisone.
4. Orange Book, FDA. Approved drug products containing Fludrocortisone acetate.

Drugs Protected by US Patent 3,950,529

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 3,950,529

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	1024076
Belgium	838231
Canada	1050890