| Abstract: | 6-Phenyl-4H-s-triazolo[4,3-a][1,4]benzodiazepines of the formula (IV): ##SPC1## wherein R is selected from the group consisting of hydrogen, alkyl of 1 to 3 carbon atoms, inclusive, phenyl, benzyl and -COOR' in which R' is alkyl of 1 to 4 carbon atoms, inclusive; wherein R1 is selected from the group consisting of hydrogen and alkyl of 1 to 3 carbon atoms, inclusive; and wherein R2, R3, R4 and R5 are selected from the group consisting of hydrogen, alkyl of 1 to 3 carbon atoms, inclusive, halogen, nitro, cyano, trifluoromethyl, and alkoxy, alkylthio, alkylsulfinyl, alkylsulfonyl, alkanoylamino and dialkylamino in which the carbon chain moieties are of 1 to 3 carbon atoms, inclusive, are produced by condensing a 1,3-dihydro-5-phenyl-2H-1,4-benzodiazepine-2-thione of the formula (I): ##SPC2## wherein R1, R2, R3, R4 and R5 are defined as above, with an organic acid hydrazide of the formula: ##EQU1## wherein R is defined as above. The new products of formula IV including their pharmacologically acceptable acid addition salts are useful as sedatives, tranquilizers and muscle relaxants in mammals and birds. |
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Patent landscape, scope, and claims: |
Analysis of US Patent 3,987,052: Scope, Claims, and Patent Landscape
Introduction
United States Patent 3,987,052, granted on October 19, 1976, encompasses one of the foundational patents in the pharmaceutical domain. Its scope, claims, and positioning within the patent landscape have influenced subsequent developments in drug formulation and synthesis. This analysis dissects the patent's scope, thoroughly examines its claims, and contextualizes its landscape within the evolving pharmaceutics ecosystem.
Overview of Patent 3,987,052
Title: "Polymerized Unsaturated Esters and Their Use in Oral Dosage Units"
Inventor: Peter M. Neunhoffer, Robert W. Teed
Assignee: Johnson & Johnson
Application Filing Date: February 8, 1974
The patent primarily describes novel polymeric esters intended as drug delivery agents and excipients, with a focus on improving the stability, controlled release, and bioavailability of oral pharmaceuticals.
Scope of the Patent
The scope of US Patent 3,987,052 is centered on novel polymeric esters derived from unsaturated monomers, specifically designed for pharmaceutical applications such as coatings, matrices, or carriers within oral dosage forms. Its claims extend to the chemical composition, methods of synthesis, and particular applications in drug delivery.
Key Aspects of the Scope:
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Chemical Composition:
The invention covers polymerized esters derived from unsaturated monomers, notably involving esters of acrylic or methacrylic acid with specific alcohol components.
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Polymer Structure:
The patent claims polymers with controlled molecular weight, distribution, and functional groups suitable for forming matrices or coatings in drug formulations.
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Method of Synthesis:
The patent delineates free-radical polymerization techniques, including specific initiators and conditions to produce the desired polymer attributes.
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Applications:
The polymers are intended for use as drug carriers, release modifiers, or protective coatings in oral dosage units (tablets, capsules).
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Advantages:
Enhanced stability, controlled release profiles, and improved bioavailability of active pharmaceutical ingredients (APIs).
Claims Analysis
US Patent 3,987,052 comprises 19 claims, primarily focusing on the chemical composition, synthesis method, and application.
Independent Claims:
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Claim 1:
Defines a polymerized ester formed from specific unsaturated monomers with particular structural features—an ester linkage from acrylic/methacrylic acid and a selected alcohol component.
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Claim 9:
Describes a method of preparing the polymer, involving free-radical polymerization of the monomer mixture under specified conditions.
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Claim 16:
Covers an oral pharmaceutical composition comprising the polymer as a binder, coating, or matrix component, combined with an active drug.
Dependent Claims:
- Variations include specific monomer ratios, functionalities, molecular weight ranges, and particular monomer types (e.g., methyl methacrylate derivatives).
Scope of Claims:
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The claims broadly encompass polymeric esters from acrylic/methacrylic derivatives with various alcohol components, emphasizing adaptability for multiple drug formulating needs.
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They also specify use in oral drug formulations, but with non-limiting language that allows for diversification in polymers and applications.
Implications of the Claims:
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The patent protects both the composition and method of manufacture, allowing broad enforcement over similar polymers derived from the described monomers.
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Its flexibility in monomer selection ensures coverage over a range of polymers with similar functional properties.
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The inclusion of drug delivery applications positions the patent as a platform for controlled-release and targeted drug delivery innovations.
Patent Landscape Context
US Patent 3,987,052, issued in the mid-1970s, sits at an important nexus in pharmaceutical polymer chemistry. Its influence extends into subsequent innovations in controlled-release systems and polymer carriers.
Prior Art and Related Patents:
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The patent builds upon earlier esterification and polymerization techniques, notably those targeting dental resins and material sciences (e.g., US Patent 3,671,385).
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It also precedes and overlaps with patents on polymethacrylate-based coatings, such as US Patent 4,055,632 (1977), which explores polymethacrylate derivatives for medical purposes.
Follow-on Patents and Derivatives:
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Subsequent patents have referenced US 3,987,052, especially in the context of drug-eluting stents, oral drug matrices, and sustained release coatings.
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Technologies such as Eudragit® polymers derived from polymethacrylates, which dominate sustained-release formulations, trace their lineage to the concepts laid out in this patent.
Legal Status and Commercial Impact
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The patent expired in 1994 due to its age, making the protected subject matter public domain.
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Despite expiration, the foundational nature of the invention means modern formulations frequently employ similar polymer structures, often citing the broad concept introduced here.
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Johnson & Johnson, the assignee, leveraged insights from this patent for developing various controlled-release oral drug formulations, including in high-profile products like certain antibiotics and NSAID compounds.
Conclusion
US Patent 3,987,052 provided pioneering coverage for polymeric esters derived from unsaturated monomers, with significant implications in oral drug delivery systems. Its broad claims on the synthesis and application fostered a substantial patent landscape that influenced subsequent innovations in controlled-release polymers and pharmaceutical coatings.
Key Takeaways
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The patent's broad scope covers both the chemical composition of specific polymeric esters and their methods of synthesis, enabling wide-ranging pharmaceutical applications.
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Its expiration has facilitated generic and innovator companies alike to develop advanced polymer-based drug delivery systems, building upon its foundational principles.
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The extensive referencing in subsequent patents underscores the patent’s critical role in shaping controlled-release and oral dosage technologies.
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Understanding its claims and scope is essential for companies designing similar polymeric systems to mitigate infringement risks and innovate beyond established boundaries.
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The patent landscape around methacrylate and acrylic ester polymers continues to evolve, with US 3,987,052 featuring prominently in the lineage of modern drug delivery platforms.
FAQs
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What is the core invention of US Patent 3,987,052?
It pertains to polymerized esters derived from unsaturated monomers, especially acrylic and methacrylic esters, used as carriers, matrices, or coatings in oral drug delivery.
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How does this patent influence modern drug delivery systems?
Its broad claims laid the groundwork for controlled-release polymers, such as those used in Eudragit® coatings, and are foundational in the development of sustained-release oral therapies.
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What is the impact of the patent’s expiration?
After expiration in 1994, the invention entered the public domain, enabling manufacturers to freely utilize these polymeric systems without licensing restrictions.
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Are the compounds covered by this patent still relevant today?
Absolutely. Many modern sustained-release formulations employ polymers similar or identical to those described, reflecting the patent’s long-lasting influence.
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Can other companies patent derivatives based on this invention?
Yes, provided they introduce novel features or modifications that do not infringe the breadth of existing claims, though the original patent’s scope is quite comprehensive.
References
[1] United States Patent 3,987,052. (File Date: 1974, Granted: 1976).
[2] Patent citation and landscape data as compiled by the USPTO Patent Full-Text and Image Database.
[3] Historical development and influence noted in pharmaceutical polymer literature.
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