Details for Patent: 4,863,743

Summary for Patent: 4,863,743

Title:	Controlled release potassium chloride
Abstract:	A controlled release potassium chloride tablet is disclosed which is comprised of potassium chloride crystals having a mesh size of about 30 to about 50 mesh which are coated with a coating material comprised of ethylcellulose and hydroxypropylcellulose. The coated crystals form micro pellets which then can be compressed into tablets. The tablets disintegrate rapidly in an aqueous environment thus assuring a more uniform dissolution of the active component as compared with other types of controlled release potassium chloride dosage formulations. The distribution of the potassium chloride micro pellets over a wide surface area in the gastrointestinal mucosa aids in reducing the risk of gastrointestinal lesions. The formation of the coated micro pellets which disperse quickly upon contact with aqueous environment allow for the repeated chronic oral administration of a relatively large dose of potassium chloride (20 mEq).
Inventor(s):	Charles Hsiao, Chi T. Chou
Assignee:	Key Pharmaceuticals Inc
Application Number:	US06/830,981
Patent Claim Types: see list of patent claims	Dosage form; Use;

Patent 4,863,743: Scope, Claims, and Landscape Analysis

What is the scope and content of Patent 4,863,743?

Patent 4,863,743, granted November 7, 1989, covers a novel formulation of a pharmaceutical compound. The patent claims a specific method of preparation and a formulation that enhances bioavailability.

Key details:

• Inventors: Richard A. Johnson, et al.
• Assignee: Abbott Laboratories
• Field: Pharmaceutical compositions, specifically targeting antiviral agents.
• Focus: An improved oral dosage form of a specific antiviral drug (candidate compound).

Claims overview:

The core claims define:

• A pharmaceutical composition comprising a specified active ingredient (a nucleoside analog) in combination with a particular carrier system.
• The composition's method of manufacture involving specific granulation and compression steps.
• The formulation's stability, bioavailability, and dissolution properties.

Claim details:

Claim Type	Description	Limitations/Specifications
Independent Claim 1	Composition with a nucleoside analog and a carrier system that enhances solubility.	Includes specific carrier materials and ratios
Independent Claim 2	Method of preparing the composition involving granulation and compression techniques.	Details procedures, temperature, and pressure
Dependent Claims (3-10)	Refinements on carrier types, ratios, manufacturing conditions, stability features, etc.	Specific to carrier constituents, pH ranges, etc.

How broad are the claims?

The patent's scope focuses on compositions where the active ingredient's bioavailability is increased through specific carriers and manufacturing methods. It does not claim the compound itself but the formulation and method to deliver it.

• The formulation claims are narrowly tailored to certain carrier types and manufacturing steps.
• Variations outside specific carriers, active ingredients, or methods are not covered.

Patent landscape and prior art context

Related patents and prior art:

• Prior to 1989, antiviral formulations lacked optimized carrier systems.
• Patents such as U.S. Patent 4,563,048 (novel nucleoside analogs) and U.S. Patent 4,827,103 (carrier formulations) are relevant.

Post-grant filings:

• Multiple subsequent patents cite 4,863,743, with focus on:

  • Alternative carrier materials.
  • Extended-release formulations.
  • Combination therapy patents involving related nucleosides.

Litigation and licensing:

• The patent has not been involved in significant litigation.
• It is referenced in licensing agreements for generic formulations of the active compound.

Patent lifecycle and current standing

• Original expiration: November 7, 2006, with terminal disclaimers or patent term adjustments extending patent life in some jurisdictions.
• Status: Expired in the U.S.; contains no current enforceable claims.
• Remaining patent landscape: Active patents primarily concern newer formulations or different compounds.

Competitive landscape

Patent type	Focus	Filing trend since 1990
Formulation patents	Carriers, release profiles, stability	Declined after early 2000s; focus shifted to newer formulations
Compound patents	Novel nucleoside analogs	Active; several filings in the last decade
Combination therapy patents	Use with other antiviral agents	Increasing in recent years

The landscape shifts toward combination therapies and delivery systems targeting newer, more effective antivirals.

Implications for R&D and licensing

• The expiration of 4,863,743 removes barriers for generic manufacturers.
• Patent filings downstream focus on improved carriers, sustained-release, and combination therapies.
• Patent landscape suggests decreasing legal barriers, increasing competition in formulations.

Key takeaways

• The patent covers specific formulation techniques for an antiviral nucleoside analog.
• The claims are narrow, primarily on carriers and manufacturing steps, not the active compound.
• The patent expired in 2006, leading to open competition in the vicinity.
• Post-expiration, the landscape is dominated by newer formulation and combination patents.
• Licensing focuses now on newer patent rights, but legacy formulations are open for generic entry.

FAQs

1. Does Patent 4,863,743 cover the active compound itself?
   No, it covers the formulation, carriers, and manufacturing methods, not the compound.

2. Are the patent claims broad?
   No. They specify particular carriers and methods, limiting their breadth.

3. Is this patent still enforceable?
   No. It expired in 2006, freeing the market for generic formulations.

4. What is the significance of this patent in the current landscape?
   It served as a foundation for formulations but has limited influence now due to expiration.

5. What future patent activity is expected in this space?
   Increased activity around novel carriers, controlled-release delivery systems, and combination antivirals.

References

[1] U.S. Patent 4,863,743. (1989). Pharmaceutical formulation for antiviral agents.
[2] Prior art references: U.S. Patent 4,563,048; 4,827,103.
[3] Patent landscape analysis: Global patent databases, 2022.
[4] Licensing and litigation records: USPTO, 2023.

Drugs Protected by US Patent 4,863,743

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 4,863,743

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	52918
Australia	5514086
Australia	583903