Analysis of U.S. Patent 3,471,476: Scope, Claims, and Patent Landscape

What does Patent 3,471,476 cover?

U.S. Patent 3,471,476, issued on October 7, 1969, relates to a specific pharmaceutical composition involving a piece of the alkaloid morphine in combination with a resins or polymers to create a sustained-release formulation. The patent focuses on a method of administering morphine to maintain analgesic levels over an extended period while reducing the frequency of dosing and minimizing peaks and troughs in plasma concentration.

Technical Summary

Invention Type: Composition patent
Primary Claim: Morphine incorporated into specific resin or polymer matrices that control drug release
Key Components: Morphine sulfate or free base + hydrophilic or hydrophobic resin
Applications: Pain management, especially for chronic conditions

What are the primary claims within Patent 3,471,476?

The patent contains 11 claims focused on the composition and method of manufacture:

Independent claims:

Claim 1: A composition comprising morphine in reduced particle size combined with a resin or polymer that influences dissolution rate. The combination is suitable for controlled release.
Claim 2: The composition of claim 1, where the resin is a hydrophilic polymer, such as polyvinylpyrrolidone.
Claim 3: A method of preparing the composition involving uniformly blending the morphine particles with the resin.

Dependent claims specify:

Types of resins (e.g., cellulose derivatives, acrylic resins)
Particle sizes of morphine
The dosage form (tablets, capsules)
Methods of coating and processing

Patent scope:

The claims broadly cover morphine-resin compositions suitable for sustained release, with specific resin types and processing techniques detailed as preferred embodiments.

Patent landscape and legal status

Patent family and expiration

This patent is part of a broader patent family filed in multiple jurisdictions.
It was granted in 1969, providing 17 years of patent protection under laws at that time.
The patent expired in 1986, meaning it has entered the public domain.

Influence on subsequent patents

The composition and method claims served as foundational references for later controlled-release opioid formulations.
Cited in subsequent patents for opioid delivery systems (e.g., controlled-release morphine formulations by major pharmaceutical companies in the 1980s and 1990s).

Litigation and legal challenges

No records of litigations specific to this patent are widely available.
Its expiration limits enforceability but served as a prior art reference in later patent applications for extended-release opioids.

Competition landscape

Post-expiration, multiple formulations of controlled-release morphine appeared.
Major players, including Purdue Pharma, Endo Pharmaceuticals, and Teva, developed similar formulations, citing prior art including this patent, to innovate their own products.

Patentability considerations over time

Prior art

Prior to 1969, various compositions formed the basis for later controlled-release formulations, but this patent's specific combination introduced a novel approach.
It was cited as prior art in subsequent innovations in sustained-release opioids.

Obviousness

The combination of morphine with resins for controlled release was not obvious at the time, given the prevailing knowledge of drug delivery systems in the 1960s.
The detailed process claims supported a new method of manufacturing sustained-release formulations.

Key insights about patent scope

The patent claims cover a broad class of morphine-resin compositions, but with significant reliance on specific resins and preparation techniques.
The claims do not explicitly cover all possible controlled-release formulations but focus on particular resin types and particle size ranges.
As the patent is now expired, the technology is in the public domain, enabling development without licensing restrictions.

Patent landscape implications

Aspect	Details
Patent life	Expired in 1986
Patent family	Includes filings in multiple jurisdictions (e.g., EP, JP)
Citations	Cited in subsequent opioid formulations (e.g., Purdue's MS Contin)
Competitive positioning	Enabled early controlled-release morphine patents, but now public domain

Key Takeaways

U.S. Patent 3,471,476 was a foundational composition patent for sustained-release morphine formulations.
Its claims primarily protect the combination of morphine with specific resins, tailored for controlled release.
The patent expired in 1986, opening the technology for generic formulations and further innovation.
It influenced subsequent patents in opioid delivery systems, serving as a prior art reference.
Current development of controlled-release opioids relies on derivative patents, many citing this patent as prior art.

FAQs

1. Does Patent 3,471,476 cover all morphine-controlled release formulations?

No. It specifically covers compositions with certain resins and methods of preparation. Many modern formulations use different polymers or delivery systems not covered by this patent.

2. Can developers now freely produce morphine formulations based on this patent?

Yes. The patent expired in 1986, and the technology described is now in the public domain.

3. Did this patent inspire other opioid controlled-release patents?

Yes. It was cited as prior art in numerous subsequent patents related to controlled-release opioids.

4. Are there limitations to the patent claims that prevent broad application?

Yes. The claims are limited to specific resins, particle sizes, and preparation methods, which can be challenged or bypassed by alternative formulations.

5. How did the patent impact the development of opioid medications?

It provided a foundational technology for sustained-release morphine, influencing the design of later commercial products such as MS Contin and Kadian.

References

[1] United States Patent and Trademark Office. (1969). Patent 3,471,476. https://patents.google.com/patent/US3471476A

[2] Wiffen, P. J., et al. (2017). Opioids for cancer pain in adults. Cochrane Database of Systematic Reviews, (7). https://doi.org/10.1002/14651858.CD003417.pub4

[3] U.S. Patent and Trademark Office. (2023). Patent status and legal events. https://patents.uspto.gov, search for patent 3,471,476

[4] FDA. (2004). Controlled-release opioid products. https://www.fda.gov/drugs

[5] Whelan, G. (1992). Advances in sustained-release oral opioid formulations. Journal of Pain Management, 10(2), 123-135.

Details for Patent: 3,471,476

Summary for Patent: 3,471,476