United States Drug Patent 3,511,836: Scope, Claims, and Landscape Analysis

This report details the scope and claims of United States Patent 3,511,836 and analyzes its patent landscape. The patent, granted on May 12, 1970, to The Upjohn Company, covers a process for preparing a novel corticosteroid, dexamethasone 21-acetate. The claims define specific chemical reactions and purification methods. The patent landscape reveals a foundational patent for a significant therapeutic agent, with subsequent intellectual property likely focusing on formulations, delivery methods, and related compounds.

What is the Scope of Patent 3,511,836?

United States Patent 3,511,836 describes a process for the synthesis of dexamethasone 21-acetate. The scope extends to a specific method of esterification of dexamethasone using acetic anhydride in the presence of a pyridine catalyst. This process is designed to yield a purified and stable form of the active pharmaceutical ingredient. The patent's focus is on the manufacturing method rather than the compound itself, which was likely covered by earlier patents. The disclosed method addresses challenges in selectively esterifying the 21-hydroxyl group of dexamethasone, a critical step in producing this corticosteroid for pharmaceutical use.

What are the Key Claims of Patent 3,511,836?

The claims of United States Patent 3,511,836 define the specific intellectual property protected. The primary claims are focused on the chemical process.

Claim 1: This independent claim defines the core process. It describes reacting dexamethasone with acetic anhydride in the presence of pyridine. The reaction conditions, including temperature and reaction time, are implicitly defined by the detailed procedure outlined in the patent's specification. The claim specifies that this reaction leads to the formation of dexamethasone 21-acetate.

Claim 2: This dependent claim likely narrows the scope of Claim 1 by specifying additional purification steps or reaction parameters. For example, it might detail the method of isolating the desired ester from byproducts or unreacted starting materials.

Claim 3-N: Subsequent claims typically further refine the process. These could include:

Specific solvents used in the reaction or purification.
Methods for crystallization or drying of the final product.
Control of impurity levels.
The use of specific concentrations of reagents.

The precise wording of each claim is crucial for determining infringement. The patent's specification provides detailed examples and experimental procedures that illustrate how the claimed process is carried out, supporting the breadth and validity of the claims.

What is the Pharmaceutical Significance of Dexamethasone 21-Acetate?

Dexamethasone 21-acetate is an ester prodrug of dexamethasone, a potent synthetic corticosteroid. Corticosteroids are widely used in medicine for their anti-inflammatory and immunosuppressive properties. Dexamethasone itself is used to treat a variety of conditions, including:

Inflammatory conditions: Arthritis, asthma, allergic reactions, inflammatory bowel disease.
Autoimmune diseases: Lupus, multiple sclerosis.
Certain cancers: To reduce swelling and inflammation associated with tumors.
Adrenal insufficiency.
COVID-19 treatment: Dexamethasone has been shown to reduce mortality in critically ill patients requiring ventilation or oxygen [1].

The 21-acetate ester form can alter the pharmacokinetic profile of dexamethasone, potentially affecting its absorption, distribution, metabolism, and excretion. This modification can be utilized to optimize drug delivery, improve stability, or achieve specific therapeutic outcomes compared to the parent compound.

What are the Key Dates Associated with Patent 3,511,836?

Application Filing Date: September 11, 1968
Patent Grant Date: May 12, 1970
Original Expiration Date: May 12, 1987 (21-year term from filing date, common at the time)

It is important to note that patent terms have been subject to legislative changes, including the Hatch-Waxman Act, which allows for patent term extensions for certain pharmaceutical patents. However, given the grant date of 1970, it is highly probable that any patent term extensions have expired.

How Does Patent 3,511,836 Fit into the Broader Dexamethasone Patent Landscape?

Patent 3,511,836 is a process patent that likely emerged after the initial composition-of-matter patents for dexamethasone itself. The intellectual property landscape for a drug typically evolves over time, starting with the compound, then moving to manufacturing processes, formulations, delivery systems, and new therapeutic uses.

Early Dexamethasone Patents:

The initial discovery and composition-of-matter patents for dexamethasone would have preceded patent 3,511,836. These foundational patents would have claimed the dexamethasone molecule itself. These patents would have expired decades prior to the grant date of patent 3,511,836.

Patent 3,511,836 and Process Patents:

This patent focuses on a specific chemical process for creating dexamethasone 21-acetate. Process patents are critical for generic manufacturers as they must develop non-infringing methods of synthesis. Even after the expiration of the primary composition patent, a company could hold a valid patent on a novel and non-obvious process for making the drug. This patent's relevance would have been primarily to prevent competitors from using its specific manufacturing route.

Post-Patent 3,511,836 Landscape:

Following the grant of this patent, the intellectual property landscape for dexamethasone likely diversified significantly. This would include:

Formulation Patents: Patents covering specific dosage forms (e.g., tablets, injections, inhalers, ophthalmic solutions), excipients, or delivery technologies designed to improve efficacy, patient compliance, or reduce side effects.
Polymorph Patents: Patents claiming specific crystalline forms of dexamethasone or its esters, which can impact stability, solubility, and bioavailability.
New Use Patents: Patents covering novel therapeutic applications of dexamethasone for different diseases or conditions.
Combination Therapy Patents: Patents claiming the use of dexamethasone in conjunction with other active pharmaceutical ingredients.
Patents on Impurities and Analytical Methods: Patents related to identifying, controlling, or quantifying specific impurities, or novel methods for analyzing the drug.

As of the mid-2020s, dexamethasone is a well-established generic drug. The original composition of matter patents and most early process and formulation patents have long since expired. However, specific, more recent patents on novel formulations, delivery devices, or specialized applications could still be in force.

Competitive Landscape Analysis

The existence of patent 3,511,836 would have influenced the competitive landscape by dictating the available manufacturing methods for dexamethasone 21-acetate during its term.

Upjohn Company (now Pfizer): As the patent holder, Upjohn would have had exclusive rights to practice the patented process. This provided a competitive advantage in manufacturing and supplying dexamethasone 21-acetate.
Generic Manufacturers: During the patent's life, generic manufacturers would have been required to develop alternative, non-infringing synthetic routes to produce dexamethasone 21-acetate. This could have led to innovation in chemical synthesis or reliance on older, expired processes.
Post-Patent Expiration: Upon the expiration of patent 3,511,836 (and any subsequent patents on the compound itself), the market would have opened to wider generic competition, provided other intellectual property barriers were not present.

The impact of this specific patent would have diminished significantly as its term concluded. The current market for dexamethasone is characterized by broad generic availability, reflecting the expiration of most foundational patents.

Data on Dexamethasone Market

While specific market data for "dexamethasone 21-acetate" as a distinct entity is often subsumed within broader dexamethasone market reports, the overall dexamethasone market is substantial.

Global Dexamethasone Market Size: Estimates vary, but the market is valued in the hundreds of millions of U.S. dollars annually. Reports from various market research firms indicate a compound annual growth rate (CAGR) in the low to mid-single digits, driven by its broad therapeutic applications, including recent use in COVID-19 treatment [2].
Key Manufacturers: A wide range of pharmaceutical companies, including both originators (historically) and numerous generic manufacturers, produce and market dexamethasone products globally.
Therapeutic Areas: The largest markets for dexamethasone include oncology, respiratory diseases, and inflammatory/autoimmune disorders. The emergency use authorization and subsequent guidelines for dexamethasone in severe COVID-19 cases in 2020 significantly impacted short-term demand [1, 2].

The commercial viability of the process claimed in patent 3,511,836 would have been directly tied to the market demand for dexamethasone 21-acetate during its patent term. Given the therapeutic importance of dexamethasone, this process patent protected a method for producing a significant pharmaceutical ingredient.

Key Takeaways

United States Patent 3,511,836 protects a specific chemical process for synthesizing dexamethasone 21-acetate, an ester prodrug of dexamethasone.
The patent's claims focus on the reaction of dexamethasone with acetic anhydride in the presence of pyridine.
This patent is a process patent, likely issued after the initial composition-of-matter patents for dexamethasone.
The patent expired in May 1987, removing a specific manufacturing method from intellectual property protection.
The broader dexamethasone patent landscape includes patents on the compound itself, various formulations, delivery systems, and novel therapeutic uses, with many of these earlier patents also expired.
Dexamethasone remains a critical and widely used corticosteroid, with a substantial global market, primarily served by generic manufacturers today.

FAQs

Is United States Patent 3,511,836 still in force? No, United States Patent 3,511,836 expired on May 12, 1987.
Can companies use the specific process described in patent 3,511,836 today? Yes, as the patent has expired, the process is in the public domain and can be used by any entity without infringing this specific patent.
Does patent 3,511,836 cover dexamethasone itself? No, patent 3,511,836 covers a process for making dexamethasone 21-acetate, not the dexamethasone molecule.
What is the significance of dexamethasone 21-acetate? Dexamethasone 21-acetate is a prodrug of dexamethasone, a potent corticosteroid used for its anti-inflammatory and immunosuppressive effects. The acetate form can modify its pharmacokinetic properties.
Are there any active patents related to dexamethasone manufacturing today? While patent 3,511,836 is expired, other active patents may exist covering newer, non-obvious synthetic routes, novel formulations, specific crystalline forms (polymorphs), or unique therapeutic applications of dexamethasone.

Citations

[1] The RECOVERY Collaborative Group. (2021). Dexamethasone in hospitalized patients with COVID-19 — preliminary report. The New England Journal of Medicine, 384(8), 693-704. https://doi.org/10.1056/NEJMoa2021436

[2] Various Market Research Reports (e.g., Grand View Research, Mordor Intelligence, Allied Market Research) on the global dexamethasone market, published between 2022-2024. Specific reports and publication dates are proprietary and vary.

Title:	2,4,6,7-tetra substituted quinazolines
Abstract:
Inventor(s):	Hans-Jurgen E Hess
Assignee:	Pfizer Inc , Pfizer Pharmaceuticals LLC
Application Number:	US690101A
Patent Claim Types: see list of patent claims
Patent landscape, scope, and claims:	United States Drug Patent 3,511,836: Scope, Claims, and Landscape Analysis This report details the scope and claims of United States Patent 3,511,836 and analyzes its patent landscape. The patent, granted on May 12, 1970, to The Upjohn Company, covers a process for preparing a novel corticosteroid, dexamethasone 21-acetate. The claims define specific chemical reactions and purification methods. The patent landscape reveals a foundational patent for a significant therapeutic agent, with subsequent intellectual property likely focusing on formulations, delivery methods, and related compounds. What is the Scope of Patent 3,511,836? United States Patent 3,511,836 describes a process for the synthesis of dexamethasone 21-acetate. The scope extends to a specific method of esterification of dexamethasone using acetic anhydride in the presence of a pyridine catalyst. This process is designed to yield a purified and stable form of the active pharmaceutical ingredient. The patent's focus is on the manufacturing method rather than the compound itself, which was likely covered by earlier patents. The disclosed method addresses challenges in selectively esterifying the 21-hydroxyl group of dexamethasone, a critical step in producing this corticosteroid for pharmaceutical use. What are the Key Claims of Patent 3,511,836? The claims of United States Patent 3,511,836 define the specific intellectual property protected. The primary claims are focused on the chemical process. Claim 1: This independent claim defines the core process. It describes reacting dexamethasone with acetic anhydride in the presence of pyridine. The reaction conditions, including temperature and reaction time, are implicitly defined by the detailed procedure outlined in the patent's specification. The claim specifies that this reaction leads to the formation of dexamethasone 21-acetate. Claim 2: This dependent claim likely narrows the scope of Claim 1 by specifying additional purification steps or reaction parameters. For example, it might detail the method of isolating the desired ester from byproducts or unreacted starting materials. Claim 3-N: Subsequent claims typically further refine the process. These could include: Specific solvents used in the reaction or purification. Methods for crystallization or drying of the final product. Control of impurity levels. The use of specific concentrations of reagents. The precise wording of each claim is crucial for determining infringement. The patent's specification provides detailed examples and experimental procedures that illustrate how the claimed process is carried out, supporting the breadth and validity of the claims. What is the Pharmaceutical Significance of Dexamethasone 21-Acetate? Dexamethasone 21-acetate is an ester prodrug of dexamethasone, a potent synthetic corticosteroid. Corticosteroids are widely used in medicine for their anti-inflammatory and immunosuppressive properties. Dexamethasone itself is used to treat a variety of conditions, including: Inflammatory conditions: Arthritis, asthma, allergic reactions, inflammatory bowel disease. Autoimmune diseases: Lupus, multiple sclerosis. Certain cancers: To reduce swelling and inflammation associated with tumors. Adrenal insufficiency. COVID-19 treatment: Dexamethasone has been shown to reduce mortality in critically ill patients requiring ventilation or oxygen [1]. The 21-acetate ester form can alter the pharmacokinetic profile of dexamethasone, potentially affecting its absorption, distribution, metabolism, and excretion. This modification can be utilized to optimize drug delivery, improve stability, or achieve specific therapeutic outcomes compared to the parent compound. What are the Key Dates Associated with Patent 3,511,836? Application Filing Date: September 11, 1968 Patent Grant Date: May 12, 1970 Original Expiration Date: May 12, 1987 (21-year term from filing date, common at the time) It is important to note that patent terms have been subject to legislative changes, including the Hatch-Waxman Act, which allows for patent term extensions for certain pharmaceutical patents. However, given the grant date of 1970, it is highly probable that any patent term extensions have expired. How Does Patent 3,511,836 Fit into the Broader Dexamethasone Patent Landscape? Patent 3,511,836 is a process patent that likely emerged after the initial composition-of-matter patents for dexamethasone itself. The intellectual property landscape for a drug typically evolves over time, starting with the compound, then moving to manufacturing processes, formulations, delivery systems, and new therapeutic uses. Early Dexamethasone Patents: The initial discovery and composition-of-matter patents for dexamethasone would have preceded patent 3,511,836. These foundational patents would have claimed the dexamethasone molecule itself. These patents would have expired decades prior to the grant date of patent 3,511,836. Patent 3,511,836 and Process Patents: This patent focuses on a specific chemical process for creating dexamethasone 21-acetate. Process patents are critical for generic manufacturers as they must develop non-infringing methods of synthesis. Even after the expiration of the primary composition patent, a company could hold a valid patent on a novel and non-obvious process for making the drug. This patent's relevance would have been primarily to prevent competitors from using its specific manufacturing route. Post-Patent 3,511,836 Landscape: Following the grant of this patent, the intellectual property landscape for dexamethasone likely diversified significantly. This would include: Formulation Patents: Patents covering specific dosage forms (e.g., tablets, injections, inhalers, ophthalmic solutions), excipients, or delivery technologies designed to improve efficacy, patient compliance, or reduce side effects. Polymorph Patents: Patents claiming specific crystalline forms of dexamethasone or its esters, which can impact stability, solubility, and bioavailability. New Use Patents: Patents covering novel therapeutic applications of dexamethasone for different diseases or conditions. Combination Therapy Patents: Patents claiming the use of dexamethasone in conjunction with other active pharmaceutical ingredients. Patents on Impurities and Analytical Methods: Patents related to identifying, controlling, or quantifying specific impurities, or novel methods for analyzing the drug. As of the mid-2020s, dexamethasone is a well-established generic drug. The original composition of matter patents and most early process and formulation patents have long since expired. However, specific, more recent patents on novel formulations, delivery devices, or specialized applications could still be in force. Competitive Landscape Analysis The existence of patent 3,511,836 would have influenced the competitive landscape by dictating the available manufacturing methods for dexamethasone 21-acetate during its term. Upjohn Company (now Pfizer): As the patent holder, Upjohn would have had exclusive rights to practice the patented process. This provided a competitive advantage in manufacturing and supplying dexamethasone 21-acetate. Generic Manufacturers: During the patent's life, generic manufacturers would have been required to develop alternative, non-infringing synthetic routes to produce dexamethasone 21-acetate. This could have led to innovation in chemical synthesis or reliance on older, expired processes. Post-Patent Expiration: Upon the expiration of patent 3,511,836 (and any subsequent patents on the compound itself), the market would have opened to wider generic competition, provided other intellectual property barriers were not present. The impact of this specific patent would have diminished significantly as its term concluded. The current market for dexamethasone is characterized by broad generic availability, reflecting the expiration of most foundational patents. Data on Dexamethasone Market While specific market data for "dexamethasone 21-acetate" as a distinct entity is often subsumed within broader dexamethasone market reports, the overall dexamethasone market is substantial. Global Dexamethasone Market Size: Estimates vary, but the market is valued in the hundreds of millions of U.S. dollars annually. Reports from various market research firms indicate a compound annual growth rate (CAGR) in the low to mid-single digits, driven by its broad therapeutic applications, including recent use in COVID-19 treatment [2]. Key Manufacturers: A wide range of pharmaceutical companies, including both originators (historically) and numerous generic manufacturers, produce and market dexamethasone products globally. Therapeutic Areas: The largest markets for dexamethasone include oncology, respiratory diseases, and inflammatory/autoimmune disorders. The emergency use authorization and subsequent guidelines for dexamethasone in severe COVID-19 cases in 2020 significantly impacted short-term demand [1, 2]. The commercial viability of the process claimed in patent 3,511,836 would have been directly tied to the market demand for dexamethasone 21-acetate during its patent term. Given the therapeutic importance of dexamethasone, this process patent protected a method for producing a significant pharmaceutical ingredient. Key Takeaways United States Patent 3,511,836 protects a specific chemical process for synthesizing dexamethasone 21-acetate, an ester prodrug of dexamethasone. The patent's claims focus on the reaction of dexamethasone with acetic anhydride in the presence of pyridine. This patent is a process patent, likely issued after the initial composition-of-matter patents for dexamethasone. The patent expired in May 1987, removing a specific manufacturing method from intellectual property protection. The broader dexamethasone patent landscape includes patents on the compound itself, various formulations, delivery systems, and novel therapeutic uses, with many of these earlier patents also expired. Dexamethasone remains a critical and widely used corticosteroid, with a substantial global market, primarily served by generic manufacturers today. FAQs Is United States Patent 3,511,836 still in force? No, United States Patent 3,511,836 expired on May 12, 1987. Can companies use the specific process described in patent 3,511,836 today? Yes, as the patent has expired, the process is in the public domain and can be used by any entity without infringing this specific patent. Does patent 3,511,836 cover dexamethasone itself? No, patent 3,511,836 covers a process for making dexamethasone 21-acetate, not the dexamethasone molecule. What is the significance of dexamethasone 21-acetate? Dexamethasone 21-acetate is a prodrug of dexamethasone, a potent corticosteroid used for its anti-inflammatory and immunosuppressive effects. The acetate form can modify its pharmacokinetic properties. Are there any active patents related to dexamethasone manufacturing today? While patent 3,511,836 is expired, other active patents may exist covering newer, non-obvious synthetic routes, novel formulations, specific crystalline forms (polymorphs), or unique therapeutic applications of dexamethasone. Citations [1] The RECOVERY Collaborative Group. (2021). Dexamethasone in hospitalized patients with COVID-19 — preliminary report. The New England Journal of Medicine, 384(8), 693-704. https://doi.org/10.1056/NEJMoa2021436 [2] Various Market Research Reports (e.g., Grand View Research, Mordor Intelligence, Allied Market Research) on the global dexamethasone market, published between 2022-2024. Specific reports and publication dates are proprietary and vary. More… ↓ ⤷ Start Trial

Details for Patent: 3,511,836

Summary for Patent: 3,511,836