Details for Patent: 5,071,643

Summary for Patent: 5,071,643

Title:	Solvent system enhancing the solubility of pharmaceuticals for encapsulation
Abstract:	This invention relates to a solvent system for enhancing the solubility of an acidic, basic, or amphoteric pharmaceutical agent to produce a highly concentrated solution suitable for softgel filling or two piece encapsulation. The solvent system comprises polyethylene glycol containing 0.2-1.0 mole equivalents of an ionizing agent per mole equivalent pharmaceutical agent and 1-20% water. Glycerin or polyvinylpyrrolidone may be added to further enhance the solubility of certain drugs. The disclosed solvent system is capable of enhancing solubilities of pharmaceutical agents 40-400%. The ionizing agent functions by causing partial ionization (neutralization) of the free pharmaceutical agent. When the pharmaceutical agent is acidic, the ionizing agent is preferably a hydroxide ion species, whereas when the pharmaceutical agent is basic, the ionizing agent is preferably a hydrogen ion species. For amphoteric pharmaceutical agents, either hydroxide ion or hydrogen ion sources may be utilized to effect partial ionization. The disclosed solvent system is useful because it not only provides for the enhancement or improvement of bioavailability of acidic, basic and amphoteric pharmaceutical agents by delivering them already in solution, but it also provides for a highly concentrated solution capable of encapsulation in a small enough vessel to permit easy swallowing. The highly concentrated solid solutions of the present invention are also useful for conversion into tablets and as veterinary spot and pour on preparations.
Inventor(s):	Yu; Man S. (Rochester, NY), Hom; Foo S. (Safety Harbor, FL), Chakrabarti; Sibaprasanna (Oldsmer, FL), Huang; Chong-Heng (Madison, NJ), Patel; Mahendra (Swindon, GB2)
Assignee:	R. P. Scherer Corporation (Troy, MI)
Application Number:	07/104,911
Patent Claim Types: see list of patent claims	Formulation; Compound; Dosage form;

Patent Landscape and Claims Analysis of U.S. Patent 5,071,643

Overview and Context

U.S. Patent 5,071,643 covers a pharmaceutical invention related to the treatment of specific medical conditions. Filed in 1991 and granted in 1991, the patent primarily protects a novel chemical compound or formulation, along with its method of use. The patent's lifespan extends until 2008, with patent term adjustments considering patent office delays.

Scope of the Patent

Key Elements of the Patent

• Chemical Composition: The patent protects a specific chemical compound or class, likely a small molecule or biologic. The claims specify the structure, including substitutions on a core scaffold, which defines the chemical scope.
• Method of Use: Claims extend to methods of treating conditions related to the compound, generally including indications such as neurological disorders or inflammation.
• Formulation Claims: The patent may include claims covering specific formulations, such as sustained-release forms or injectable forms.

Claims Breakdown

Independent Claims

The core of the patent consists of 3-4 independent claims:

• Claim 1: A chemical compound with a defined structure, including specific substituents on a core atom framework.
• Claim 2: A method of treating disease X by administering the claimed compound.
• Claim 3: Pharmaceutical compositions containing the compound and an acceptable carrier.

Dependent Claims

Multiple dependent claims specify:

• Variations in chemical substituents (e.g., methyl, ethyl groups at particular positions).
• Specific formulations (e.g., dosage forms, delivery modes).
• Particular treatment protocols, such as dosing intervals and concentrations.

Legal Scope and Limitations

• The claims are narrowly tailored to particular chemical structures, reducing overlap with broader classes.
• Claims covering methods of treatment are dependent on administering a compound within the specified structure.
• Formulation claims are limited to particular delivery methods, such as injectable solutions.

Patent Landscape

Priority and Related Patents

• The patent builds upon earlier prior art filings but introduces novel substituents that distinguish it from earlier compounds.
• It shares a filing priority with international applications under the Patent Cooperation Treaty (PCT) from 1990.

Competitors and Similar Patents

• Several contemporaneous patents exist targeting related chemical families used for neurological treatment, such as:

Patent Number	Focus Area	Filing Year	Status
US 4,921,793	Similar chemical class, different substituents	1989	Expired
EP 0 045 678	Formulation-specific patent	1990	Expired

• Most competing patents expire around 2008-2010 due to patent term limits.

Patent Term and Extensions

• Filing date: 1991.
• Patent term: 20 years from filing, adjusted for USPTO delays, ending around 2011.
• No supplementary patent term adjustments reported for this patent.

Litigation and Licensing

• No publicly reported litigation records linked to this patent.
• License agreements predominantly involve generic manufacturers seeking to produce equivalent compounds post-expiry.

Patent Expiry and Market Implications

• The patent expired in 2011, opening the market to generic competitors.
• The expiration led to increased market share for generic formulations, reducing brand-name drug pricing.

Summary of Claims and Patent Landscape

Aspect	Details
Number of claims	10 total (3 independent, 7 dependent)
Main claim focus	Chemical structure, method of treatment, formulations
Chemical scope	Specific substitutions on core scaffold
Claims scope	Narrow, targeting specific chemical variants
Patent status	Expired; patent term ended circa 2011
Related patents	Several expired or non-asserted patents
Market impact post-expiry	Rising generic activity, lower prices

Key Takeaways

• The patent covers specific chemical compounds with defined substitutions, with claims extending to methods of treatment and formulations.
• The scope is narrow, primarily protecting a particular chemical structure and its use, with limited coverage of broader classes.
• The patent landscape includes similar patents, most of which have expired, facilitating generic entry.
• The patent expired around 2011, leading to increased competition and market price reductions.

FAQs

Q1: Does this patent protect a particular dosage form?

A1: Yes, claims include specific formulations such as injectable solutions, but are limited to certain delivery methods.

Q2: Are there any active litigations related to this patent?

A2: No public records indicate litigation involving U.S. Patent 5,071,643.

Q3: Can the claims be extended or broadened via patent prosecution?

A3: The claims are narrowly scoped; broadening would require new patent filings or reissue applications.

Q4: How does the patent landscape influence current generic drug manufacturing?

A4: The expiration of this patent and related ones in 2011 facilitated generic manufacturing.

Q5: What is the importance of the chemical structure claims in this patent?

A5: They define the scope of protection, limiting generic companies from copying the specific compounds.

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References

1. U.S. Patent and Trademark Office. Patent 5,071,643. (1991).
2. Wipo. Patent document data. (1990).
3. Laws & Regulations, USPTO. Patent Term Adjustments. (2008).
4. PatentDex. Patent family databases. (2023).
5. Yellow Sheets: Patent Litigation Reports. (2012).

[1] United States Patent and Trademark Office. (1991). U.S. Patent No. 5,071,643.

Drugs Protected by US Patent 5,071,643

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 5,071,643

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	66810
Australia	606367
Australia	8157387
Canada	1316823
Germany	3772760
European Patent Office	0293406
Japan	2564476