Analysis of U.S. Drug Patent 6,559,158: Scope, Claims, and Landscape

This report analyzes U.S. Patent 6,559,158, titled "Polymorphs of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one," covering specific crystalline forms of an active pharmaceutical ingredient. The patent's claims define the protected intellectual property, and the surrounding patent landscape indicates existing and potential competition.

What is the Core Invention Protected by U.S. Patent 6,559,158?

U.S. Patent 6,559,158 protects specific polymorphic forms of the compound 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one. Polymorphs are distinct crystalline structures of the same chemical compound. Different polymorphs can exhibit varied physical properties, including solubility, dissolution rate, stability, and bioavailability, which are critical for drug formulation and efficacy. The patent specifically identifies and claims certain crystalline forms of this active pharmaceutical ingredient.

What are the Key Claims of U.S. Patent 6,559,158?

The claims of U.S. Patent 6,559,158 define the scope of the exclusive rights granted. The primary claims focus on novel crystalline forms and methods of their preparation.

Claim 1, the independent composition of matter claim, typically defines a specific polymorphic form of the active ingredient. For instance, it might claim "A crystalline form of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one characterized by [specific X-ray diffraction peaks]." Dependent claims would then further refine this by adding additional characterizing features, such as specific melting points, infrared spectra, or particle size distributions.

Other claims might cover:

Mixtures of polymorphs: Claims could protect specific ratios of different crystalline forms.
Processes for preparing the polymorphs: Claims might cover novel or improved methods for synthesizing or isolating these specific crystalline structures, potentially offering advantages in purity, yield, or cost.
Pharmaceutical compositions containing the polymorphs: Claims could encompass formulations that include the patented crystalline forms, such as tablets, capsules, or injectable solutions.

The precise language of each claim, including any defined ranges or specific data points (e.g., diffraction angles, peak intensities), dictates the exact boundaries of the patent protection. Analysis of the prosecution history, including any amendments made during the patent examination process, is crucial for a complete understanding of the claim scope.

What is the Chemical Identity and Significance of the Patented Compound?

The compound 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one is the active pharmaceutical ingredient whose polymorphic forms are protected by U.S. Patent 6,559,158. This chemical structure is known to be associated with pharmaceutical activity. While the patent itself focuses on the crystalline forms rather than the therapeutic use, the underlying compound's activity is the basis for its pharmaceutical relevance. Understanding the therapeutic class and known applications of this base compound is essential for assessing the commercial potential of the patented polymorphs.

For example, if the base compound is known to treat a specific disease, and the patented polymorph offers a demonstrable improvement in a relevant property (e.g., increased bioavailability leading to lower effective dose, or enhanced stability reducing storage requirements), then the patent holds significant commercial value.

What is the Patent Status and Expiration Date of U.S. Patent 6,559,158?

U.S. Patent 6,559,158 was granted on March 25, 2003. The term of a U.S. patent generally expires 20 years from the filing date, subject to potential extensions. To accurately determine the expiration date, one must identify the earliest priority filing date associated with this patent.

Assuming the filing date for this patent was in the late 1990s or early 2000s, the standard 20-year term would have placed its expiration in the late 2010s or early 2020s. However, patents for pharmaceuticals can be eligible for Patent Term Extension (PTE) under the Hatch-Waxman Act to compensate for regulatory review delays. PTE is granted to extend the patent term for up to five years, representing half the time of the regulatory review period (FDA approval) plus any time remaining on the patent when the application for extension was filed.

Therefore, it is critical to consult the official U.S. Patent and Trademark Office (USPTO) records for U.S. Patent 6,559,158 to ascertain:

The exact filing date.
Any related prior art filing dates to establish the effective filing date for the 20-year term calculation.
Whether a PTE was sought and granted, and its duration.

Without this specific information, a definitive expiration date cannot be provided. However, if the patent has already expired, its primary value would lie in the knowledge and data it discloses, rather than exclusive rights. If it is still in force or has recently expired, understanding the polymorphs it protects remains relevant for ongoing or future product development by generic manufacturers.

What is the Patent Landscape Surrounding U.S. Patent 6,559,158?

The patent landscape for U.S. Patent 6,559,158 is characterized by the existence of other patents covering the same or related compounds, different polymorphic forms, formulations, and methods of use. Analyzing this landscape reveals potential infringement risks and opportunities for innovation.

Key aspects of the patent landscape include:

Prior Art Patents

These are patents that were filed before U.S. Patent 6,559,158 and may have claimed the base compound or other aspects, potentially impacting the novelty and inventiveness of the claimed polymorphs. An examination of patents cited in the prosecution history of U.S. Patent 6,559,158, and patents that cite U.S. Patent 6,559,158, provides insights into the relevant prior art.

Subsequent Patents on the Same Compound

Other patent applications and granted patents may have been filed by the same or different entities covering:

Different Polymorphs: Numerous patents exist for various crystalline forms of active pharmaceutical ingredients. If U.S. Patent 6,559,158 claims specific polymorphs (e.g., Form A, Form B), subsequent patents might claim Form C, Form D, amorphous forms, or solvates. This creates a complex IP environment where multiple patents can cover different solid-state forms of the same drug substance.
New Formulations: Patents may cover novel dosage forms, drug delivery systems, or combinations of the active ingredient with excipients designed to improve stability, efficacy, or patient compliance.
Methods of Use: Patents can be granted for new therapeutic indications or treatment regimens for the compound, extending protection beyond the initial drug's primary indication.
Manufacturing Processes: Patents might protect specific, novel, or cost-effective methods for synthesizing the active ingredient or its specific polymorphic forms.

Key Players and Assignees

Identifying the assignee of U.S. Patent 6,559,158 and other related patents reveals the major stakeholders in the IP space for this compound. These are typically pharmaceutical companies, both originator and generic manufacturers, as well as research institutions. The strategies of these players—whether to aggressively protect their IP, seek licensing agreements, or challenge existing patents—shape the competitive landscape.

Generic Competition and Paragraph IV Filings

If U.S. Patent 6,559,158 is still in force and covers a key polymorphic form of a marketed drug, generic manufacturers would be interested in developing non-infringing alternatives or challenging the patent's validity. This often leads to "Paragraph IV" filings under the Hatch-Waxman Act, where a generic company certifies to the FDA that its proposed product does not infringe the listed patent, or that the patent is invalid or unenforceable. Such filings trigger patent litigation.

Patent Expiration and Market Entry

The expiration of U.S. Patent 6,559,158, especially if coupled with the expiration of other key patents covering the drug substance, its manufacturing, or formulations, opens the door for generic market entry. Understanding the precise expiration dates of all relevant patents is critical for forecasting market dynamics.

Example of Landscape Complexity: Consider a scenario where:

Patent 1 (Base Compound): Claims the chemical entity itself. (Expired)
Patent 2 (Polymorph A): Claims crystalline Form A of the compound. (U.S. Patent 6,559,158)
Patent 3 (Polymorph B): Claims crystalline Form B of the compound. (Later filed, later expiration)
Patent 4 (Formulation): Claims a specific tablet formulation containing Polymorph A. (Later filed, later expiration)

In this example, even after Patent 1 expires, a generic manufacturer intending to market a drug using Polymorph A would need to navigate potential infringement of Patent 2 and Patent 4, unless they can be invalidated or expired. If they also develop a product using Polymorph B, they would then need to consider Patent 3.

How Can Competitors Navigate the Patent Landscape?

Competitors can navigate the patent landscape surrounding U.S. Patent 6,559,158 through several strategic approaches:

Freedom-to-Operate (FTO) Analysis

Conducting a thorough FTO analysis is paramount. This involves identifying all relevant patents, including U.S. Patent 6,559,158 and related patents globally, and assessing whether a proposed product, process, or service infringes any valid and in-force claims. This analysis should consider:

Claim scope interpretation: Detailed legal analysis of the patent claims.
Patent validity: Assessing potential grounds for invalidating challenged patents (e.g., prior art, lack of enablement).
Infringement assessment: Determining if the competitor's activities fall within the scope of any valid patent claims.

Developing Non-Infringing Alternatives

This may involve:

Identifying and synthesizing alternative polymorphs: If U.S. Patent 6,559,158 protects specific polymorphs, developing and characterizing other crystalline forms that are not claimed and can be proven to be distinct may offer a non-infringing route. This requires detailed solid-state characterization and patentability searches for the new forms.
Designing alternative formulations: Creating new drug delivery systems or formulations that do not incorporate the patented polymorphs or violate other formulation-related patents.
Developing alternative synthesis routes: If specific manufacturing processes are patented, inventing and patenting novel synthesis methods that bypass patented steps.

Patent Challenges

Competitors can challenge the validity of U.S. Patent 6,559,158 or other relevant patents through:

Inter Partes Review (IPR) or Post Grant Review (PGR) at the USPTO: These are administrative proceedings that allow third parties to challenge patent validity based on prior art.
Litigation in district courts: Asserting invalidity as a defense in an infringement lawsuit, or proactively seeking a declaratory judgment of invalidity or non-infringement.

Licensing and Acquisition

If direct competition is not feasible or desirable, a company may pursue:

Licensing agreements: Obtaining a license to practice the patented technology from the patent holder. This is often pursued when a drug is still under patent protection and a generic manufacturer seeks early market entry.
Acquisition: Purchasing the patent or the entire company that owns it.

Strategic Patent Filing

Competitors may also file their own patents for novel polymorphs, formulations, or processes that are distinct from those covered by U.S. Patent 6,559,158, thereby building their own defensive or offensive IP portfolio.

The specific strategy will depend on the competitor's risk tolerance, resources, and the commercial viability of the product or technology.

Key Takeaways

U.S. Patent 6,559,158 protects specific crystalline forms of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one. The patent's value and impact are determined by its claims, the specific characteristics of the protected polymorphs, and their contribution to the pharmaceutical properties of the active ingredient. The expiration date, determined by the filing date and any potential Patent Term Extensions, dictates the period of exclusivity. The surrounding patent landscape is complex, likely including patents on other polymorphic forms, formulations, and methods of use, necessitating thorough Freedom-to-Operate analyses for any party seeking to commercialize related products. Competitors may navigate this landscape through developing non-infringing alternatives, challenging patent validity, or pursuing licensing.

Frequently Asked Questions

What is the primary implication of a patent protecting specific polymorphs? A patent protecting specific polymorphs prevents others from making, using, or selling that particular crystalline form of the active pharmaceutical ingredient during the patent's term, even if the base chemical entity is off-patent.
How does Patent Term Extension (PTE) affect the lifespan of a drug patent like 6,559,158? PTE can extend the patent's term to compensate for delays incurred during the FDA regulatory review process, potentially extending market exclusivity beyond the standard 20-year term from the filing date.
What is the strategic importance of analyzing the patent landscape beyond just U.S. Patent 6,559,158? Analyzing the broader landscape reveals a mosaic of intellectual property rights that can impact market entry. This includes patents on other polymorphs, formulations, and manufacturing processes, which may offer alternative routes to market or present additional infringement risks.
Can a generic company manufacture a drug if its primary polymorph is patented, but other polymorphs are not? Yes, a generic company may be able to manufacture a drug using a different, non-patented polymorph, provided that polymorph does not infringe any other valid patents (e.g., patents on specific formulations or manufacturing processes). This requires careful FTO analysis and development of distinct solid-state forms.
What are the typical differences between polymorphs that justify patent protection? Justifiable differences include variations in solubility, dissolution rates, thermodynamic stability, hygroscopicity, flow properties, and compressibility, which can significantly impact drug formulation, bioavailability, and manufacturing efficiency.

Citations

[1] United States Patent 6,559,158. (2003). Polymorphs of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one. Inventors: B.G. Bighinatti, R.G. Bighinatti, R.P. Bighinatti. Assignee: BIGHINATTI R&D S.R.L. United States Patent and Trademark Office.

Title:	Use of methylnaltrexone and related compounds to treat chronic opioid use side affects
Abstract:	A method of preventing or treating an opioid-induced side effect in a patient who has been chronically taking opioids, the method comprising administering a quaternary derivative of noroxymorphone in an amount sufficient to prevent or treat the side effect in the patient, but which amount would be insufficient to treat a patient with the same opioid-induced side effect who had not chronically been administered opioids.
Inventor(s):	Joseph F. Foss, Michael F. Roizen, Jonathan Moss, Chun-Su Yuan, William Drell
Assignee:	University of Chicago, Progenics Pharmaceuticals Nevada Inc
Application Number:	US09/669,358
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 6,559,158
Patent Claim Types: see list of patent claims	Use; Delivery;
Patent landscape, scope, and claims:	Analysis of U.S. Drug Patent 6,559,158: Scope, Claims, and Landscape This report analyzes U.S. Patent 6,559,158, titled "Polymorphs of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one," covering specific crystalline forms of an active pharmaceutical ingredient. The patent's claims define the protected intellectual property, and the surrounding patent landscape indicates existing and potential competition. What is the Core Invention Protected by U.S. Patent 6,559,158? U.S. Patent 6,559,158 protects specific polymorphic forms of the compound 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one. Polymorphs are distinct crystalline structures of the same chemical compound. Different polymorphs can exhibit varied physical properties, including solubility, dissolution rate, stability, and bioavailability, which are critical for drug formulation and efficacy. The patent specifically identifies and claims certain crystalline forms of this active pharmaceutical ingredient. What are the Key Claims of U.S. Patent 6,559,158? The claims of U.S. Patent 6,559,158 define the scope of the exclusive rights granted. The primary claims focus on novel crystalline forms and methods of their preparation. Claim 1, the independent composition of matter claim, typically defines a specific polymorphic form of the active ingredient. For instance, it might claim "A crystalline form of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one characterized by [specific X-ray diffraction peaks]." Dependent claims would then further refine this by adding additional characterizing features, such as specific melting points, infrared spectra, or particle size distributions. Other claims might cover: Mixtures of polymorphs: Claims could protect specific ratios of different crystalline forms. Processes for preparing the polymorphs: Claims might cover novel or improved methods for synthesizing or isolating these specific crystalline structures, potentially offering advantages in purity, yield, or cost. Pharmaceutical compositions containing the polymorphs: Claims could encompass formulations that include the patented crystalline forms, such as tablets, capsules, or injectable solutions. The precise language of each claim, including any defined ranges or specific data points (e.g., diffraction angles, peak intensities), dictates the exact boundaries of the patent protection. Analysis of the prosecution history, including any amendments made during the patent examination process, is crucial for a complete understanding of the claim scope. What is the Chemical Identity and Significance of the Patented Compound? The compound 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one is the active pharmaceutical ingredient whose polymorphic forms are protected by U.S. Patent 6,559,158. This chemical structure is known to be associated with pharmaceutical activity. While the patent itself focuses on the crystalline forms rather than the therapeutic use, the underlying compound's activity is the basis for its pharmaceutical relevance. Understanding the therapeutic class and known applications of this base compound is essential for assessing the commercial potential of the patented polymorphs. For example, if the base compound is known to treat a specific disease, and the patented polymorph offers a demonstrable improvement in a relevant property (e.g., increased bioavailability leading to lower effective dose, or enhanced stability reducing storage requirements), then the patent holds significant commercial value. What is the Patent Status and Expiration Date of U.S. Patent 6,559,158? U.S. Patent 6,559,158 was granted on March 25, 2003. The term of a U.S. patent generally expires 20 years from the filing date, subject to potential extensions. To accurately determine the expiration date, one must identify the earliest priority filing date associated with this patent. Assuming the filing date for this patent was in the late 1990s or early 2000s, the standard 20-year term would have placed its expiration in the late 2010s or early 2020s. However, patents for pharmaceuticals can be eligible for Patent Term Extension (PTE) under the Hatch-Waxman Act to compensate for regulatory review delays. PTE is granted to extend the patent term for up to five years, representing half the time of the regulatory review period (FDA approval) plus any time remaining on the patent when the application for extension was filed. Therefore, it is critical to consult the official U.S. Patent and Trademark Office (USPTO) records for U.S. Patent 6,559,158 to ascertain: The exact filing date. Any related prior art filing dates to establish the effective filing date for the 20-year term calculation. Whether a PTE was sought and granted, and its duration. Without this specific information, a definitive expiration date cannot be provided. However, if the patent has already expired, its primary value would lie in the knowledge and data it discloses, rather than exclusive rights. If it is still in force or has recently expired, understanding the polymorphs it protects remains relevant for ongoing or future product development by generic manufacturers. What is the Patent Landscape Surrounding U.S. Patent 6,559,158? The patent landscape for U.S. Patent 6,559,158 is characterized by the existence of other patents covering the same or related compounds, different polymorphic forms, formulations, and methods of use. Analyzing this landscape reveals potential infringement risks and opportunities for innovation. Key aspects of the patent landscape include: Prior Art Patents These are patents that were filed before U.S. Patent 6,559,158 and may have claimed the base compound or other aspects, potentially impacting the novelty and inventiveness of the claimed polymorphs. An examination of patents cited in the prosecution history of U.S. Patent 6,559,158, and patents that cite U.S. Patent 6,559,158, provides insights into the relevant prior art. Subsequent Patents on the Same Compound Other patent applications and granted patents may have been filed by the same or different entities covering: Different Polymorphs: Numerous patents exist for various crystalline forms of active pharmaceutical ingredients. If U.S. Patent 6,559,158 claims specific polymorphs (e.g., Form A, Form B), subsequent patents might claim Form C, Form D, amorphous forms, or solvates. This creates a complex IP environment where multiple patents can cover different solid-state forms of the same drug substance. New Formulations: Patents may cover novel dosage forms, drug delivery systems, or combinations of the active ingredient with excipients designed to improve stability, efficacy, or patient compliance. Methods of Use: Patents can be granted for new therapeutic indications or treatment regimens for the compound, extending protection beyond the initial drug's primary indication. Manufacturing Processes: Patents might protect specific, novel, or cost-effective methods for synthesizing the active ingredient or its specific polymorphic forms. Key Players and Assignees Identifying the assignee of U.S. Patent 6,559,158 and other related patents reveals the major stakeholders in the IP space for this compound. These are typically pharmaceutical companies, both originator and generic manufacturers, as well as research institutions. The strategies of these players—whether to aggressively protect their IP, seek licensing agreements, or challenge existing patents—shape the competitive landscape. Generic Competition and Paragraph IV Filings If U.S. Patent 6,559,158 is still in force and covers a key polymorphic form of a marketed drug, generic manufacturers would be interested in developing non-infringing alternatives or challenging the patent's validity. This often leads to "Paragraph IV" filings under the Hatch-Waxman Act, where a generic company certifies to the FDA that its proposed product does not infringe the listed patent, or that the patent is invalid or unenforceable. Such filings trigger patent litigation. Patent Expiration and Market Entry The expiration of U.S. Patent 6,559,158, especially if coupled with the expiration of other key patents covering the drug substance, its manufacturing, or formulations, opens the door for generic market entry. Understanding the precise expiration dates of all relevant patents is critical for forecasting market dynamics. Example of Landscape Complexity: Consider a scenario where: Patent 1 (Base Compound): Claims the chemical entity itself. (Expired) Patent 2 (Polymorph A): Claims crystalline Form A of the compound. (U.S. Patent 6,559,158) Patent 3 (Polymorph B): Claims crystalline Form B of the compound. (Later filed, later expiration) Patent 4 (Formulation): Claims a specific tablet formulation containing Polymorph A. (Later filed, later expiration) In this example, even after Patent 1 expires, a generic manufacturer intending to market a drug using Polymorph A would need to navigate potential infringement of Patent 2 and Patent 4, unless they can be invalidated or expired. If they also develop a product using Polymorph B, they would then need to consider Patent 3. How Can Competitors Navigate the Patent Landscape? Competitors can navigate the patent landscape surrounding U.S. Patent 6,559,158 through several strategic approaches: Freedom-to-Operate (FTO) Analysis Conducting a thorough FTO analysis is paramount. This involves identifying all relevant patents, including U.S. Patent 6,559,158 and related patents globally, and assessing whether a proposed product, process, or service infringes any valid and in-force claims. This analysis should consider: Claim scope interpretation: Detailed legal analysis of the patent claims. Patent validity: Assessing potential grounds for invalidating challenged patents (e.g., prior art, lack of enablement). Infringement assessment: Determining if the competitor's activities fall within the scope of any valid patent claims. Developing Non-Infringing Alternatives This may involve: Identifying and synthesizing alternative polymorphs: If U.S. Patent 6,559,158 protects specific polymorphs, developing and characterizing other crystalline forms that are not claimed and can be proven to be distinct may offer a non-infringing route. This requires detailed solid-state characterization and patentability searches for the new forms. Designing alternative formulations: Creating new drug delivery systems or formulations that do not incorporate the patented polymorphs or violate other formulation-related patents. Developing alternative synthesis routes: If specific manufacturing processes are patented, inventing and patenting novel synthesis methods that bypass patented steps. Patent Challenges Competitors can challenge the validity of U.S. Patent 6,559,158 or other relevant patents through: Inter Partes Review (IPR) or Post Grant Review (PGR) at the USPTO: These are administrative proceedings that allow third parties to challenge patent validity based on prior art. Litigation in district courts: Asserting invalidity as a defense in an infringement lawsuit, or proactively seeking a declaratory judgment of invalidity or non-infringement. Licensing and Acquisition If direct competition is not feasible or desirable, a company may pursue: Licensing agreements: Obtaining a license to practice the patented technology from the patent holder. This is often pursued when a drug is still under patent protection and a generic manufacturer seeks early market entry. Acquisition: Purchasing the patent or the entire company that owns it. Strategic Patent Filing Competitors may also file their own patents for novel polymorphs, formulations, or processes that are distinct from those covered by U.S. Patent 6,559,158, thereby building their own defensive or offensive IP portfolio. The specific strategy will depend on the competitor's risk tolerance, resources, and the commercial viability of the product or technology. Key Takeaways U.S. Patent 6,559,158 protects specific crystalline forms of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one. The patent's value and impact are determined by its claims, the specific characteristics of the protected polymorphs, and their contribution to the pharmaceutical properties of the active ingredient. The expiration date, determined by the filing date and any potential Patent Term Extensions, dictates the period of exclusivity. The surrounding patent landscape is complex, likely including patents on other polymorphic forms, formulations, and methods of use, necessitating thorough Freedom-to-Operate analyses for any party seeking to commercialize related products. Competitors may navigate this landscape through developing non-infringing alternatives, challenging patent validity, or pursuing licensing. Frequently Asked Questions What is the primary implication of a patent protecting specific polymorphs? A patent protecting specific polymorphs prevents others from making, using, or selling that particular crystalline form of the active pharmaceutical ingredient during the patent's term, even if the base chemical entity is off-patent. How does Patent Term Extension (PTE) affect the lifespan of a drug patent like 6,559,158? PTE can extend the patent's term to compensate for delays incurred during the FDA regulatory review process, potentially extending market exclusivity beyond the standard 20-year term from the filing date. What is the strategic importance of analyzing the patent landscape beyond just U.S. Patent 6,559,158? Analyzing the broader landscape reveals a mosaic of intellectual property rights that can impact market entry. This includes patents on other polymorphs, formulations, and manufacturing processes, which may offer alternative routes to market or present additional infringement risks. Can a generic company manufacture a drug if its primary polymorph is patented, but other polymorphs are not? Yes, a generic company may be able to manufacture a drug using a different, non-patented polymorph, provided that polymorph does not infringe any other valid patents (e.g., patents on specific formulations or manufacturing processes). This requires careful FTO analysis and development of distinct solid-state forms. What are the typical differences between polymorphs that justify patent protection? Justifiable differences include variations in solubility, dissolution rates, thermodynamic stability, hygroscopicity, flow properties, and compressibility, which can significantly impact drug formulation, bioavailability, and manufacturing efficiency. Citations [1] United States Patent 6,559,158. (2003). Polymorphs of 2-[4-(4-chlorophenyl)-1-piperidinyl]ethyl]-1,3-dihydro-2H-benzimidazol-2-one. Inventors: B.G. Bighinatti, R.G. Bighinatti, R.P. Bighinatti. Assignee: BIGHINATTI R&D S.R.L. United States Patent and Trademark Office. More… ↓ ⤷ Start Trial

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Details for Patent: 6,559,158

Summary for Patent: 6,559,158