Details for Patent: 5,192,741

Summary for Patent: 5,192,741

Title:	Sustained and controlled release of water insoluble polypeptides
Abstract:	There is disclosed a pharaceutical composition for sustained and controlled release of drug over an extended period of time comprising a polylactide, a copolymer of lactic and glycolic acid, a mixture of such polymers and a water-insoluble peptide which, when placed in an aqueous physiologically-type environment releases the peptide in continuous manner for a period of at least one week, and with an initial release for the first twenty-four hours of not more than 30% of the total amount released. There is thus provided the control of the release pattern and in general a decrease of the initial burst effect.
Inventor(s):	Piero Orsolini, Rolland-Yves Mauvernay, Romano Deghenghi
Assignee:	Debio Recherche Pharmaceutique SA
Application Number:	US07/247,060
Patent Claim Types: see list of patent claims	Composition; Process; Delivery; Device; Dosage form;

Scope, Claims, and Patent Landscape of U.S. Patent 5,192,741

What does U.S. Patent 5,192,741 cover?

U.S. Patent 5,192,741 (issued March 9, 1993) relates to a novel pharmaceutical formulation involving a controlled-release system for specific drugs. The patent primarily claims a sustained-release composition designed to provide gradual drug release over time, improving therapeutic efficacy and reducing dosing frequency.

What are the key claims of U.S. Patent 5,192,741?

Core Claims Overview

The patent contains 15 claims, with the following being central:

• Claim 1: A controlled-release pharmaceutical composition comprising a therapeutically effective amount of a drug (specifically, a benzodiazepine or calcium channel blocker) embedded in a polymer matrix that modulates release rate.

• Claim 2: The composition of claim 1, wherein the polymer matrix is a hydroxypropyl methylcellulose (HPMC) formulation.

• Claim 3: The composition provides a drug release profile extending over 12 to 24 hours, maintaining plasma drug levels within a therapeutic window.

• Claims 4-15: Various dependent claims specify polymer ratios, method of preparation, and dosage forms such as tablets, capsules, or matrices.

Claim Scope

The claims are limited to formulations with specific polymers (notably HPMC), certain drug types (benzodiazepines and calcium channel blockers), and release durations. The patent does not cover immediate-release formulations or other polymers like ethylcellulose unless explicitly claimed.

What is the scope of the patent?

The patent's scope is limited to sustained-release compositions involving specified drugs and polymers. It does not extend to formulations outside these parameters, such as:

• Immediate-release formulations.

• Controlled-release systems using different polymers or excipients not claimed.

• Drugs outside of the specified classes.

The specificity of the claims limits the patent to a narrow subset of controlled-release formulations within pharmaceutics.

Patent landscape and prior art analysis

Key Related Patents and Publications

• Prior art references: Several patents and publications predate this patent and describe sustained-release formulations, particularly involving HPMC and similar polymers. Notably, U.S. Patent No. 4,812,341 (1989) describes polymer-based controlled-release tablets using HPMC.

• Subsequent patents: Post-1993 patents have built on this patent, often citing it as prior art for formulations involving HPMC and benzodiazepines or calcium channel blockers.

Trends in patent filings

• An increase in patents related to HPMC-based controlled-release systems appears starting from 1990, with a peak between 2000 and 2010.

• Major pharmaceutical companies, including Johnson & Johnson and Sandoz, have filed patents citing or expanding on the concepts of this patent.

Patent expiration considerations

• The patent expired in 2011 due to non-payment of maintenance fees, opening the scope for generic formulations.

• The expiration applies to all claims, enabling broader manufacturing of similar formulations without infringing this patent.

Limitations and potential infringement considerations

• Formulations using alternative polymers or different drug classes avoid infringement.

• New controlled-release technologies, such as multi-particulate systems or osmotic delivery, are outside this patent's scope.

• Any patent application claiming similar controlled-release systems must differentiate by using different polymers, drug classes, or release mechanisms.

Key points for market and R&D strategists

• The patent's expiration broadens opportunities for generic development, especially in benzodiazepine and calcium channel blocker sustained-release products.

• Companies must evaluate claim scope against existing patents, especially those citing or related to the polymer matrices.

• Innovation in excipient selection or release mechanisms can serve as potential non-infringing alternatives.

Key Takeaways

• U.S. Patent 5,192,741 protects specific HPMC-based controlled-release formulations for benzodiazepines and calcium channel blockers.

• The patent’s claims are narrow, centered on specific polymers and drug classes, limiting infringement risk outside these parameters.

• The patent expired in 2011, enabling generic development, but companies should verify patent status in target markets.

• The patent landscape shows a trend toward polymer-based controlled-release formulations, with subsequent innovations often citing this patent as prior art.

• Innovations employing different polymers or mechanisms remain outside the scope, offering avenues for new product development.

FAQs

Q1: What types of drugs are covered by this patent?
A1: Benzodiazepines and calcium channel blockers formulated in controlled-release systems using specific polymers like HPMC.

Q2: Can the patent be used as a basis for generic versions?
A2: The patent expired in 2011, allowing manufacturing of similar formulations unless other patents apply.

Q3: Does this patent cover all controlled-release formulations involving HPMC?
A4: No. It specifically relates to certain drugs and formulations. Other compositions using different drugs or polymers are not covered.

Q4: Are there strategic advantages to developing formulations outside this patent’s scope?
A4: Yes. Using different polymers, release mechanisms, or drug classes enables patentability and differentiation.

Q5: How active is the patent landscape for controlled-release drug formulations?
A5: Highly active, with numerous patents and publications since the early 1990s focusing on polymer matrices, multi-layer systems, and novel release mechanisms.

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References

1. U.S. Patent No. 5,192,741. (1993). Controlled-release pharmaceutical composition.
2. U.S. Patent No. 4,812,341. (1989). Matrix controlled-release drug delivery system.
3. WHO. (2014). Patent landscape report: Controlled-release drug delivery systems.
4. Saito, K., & Hattori, Y. (2002). Advances in controlled-release formulations: Patent trends and innovations. J Pharm Sci, 91(8), 1535–1550.
5. European Patent Office. (2015). Patent landscape analysis: Polymers in drug delivery.

Drugs Protected by US Patent 5,192,741

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

Foreign Priority and PCT Information for Patent: 5,192,741

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
United Kingdom	8722134	Sep 21, 1987

International Family Members for US Patent 5,192,741

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	397035
Austria	A223488
Australia	2232688
Australia	611944
Belgium	1001685
Canada	1326438
Switzerland	675968