Detailed Analysis of the Scope and Claims of United States Patent 6,071,523
Introduction
United States Patent 6,071,523, titled "Spill-Resistant Pharmaceutical Formulations," is a significant patent in the field of pharmaceuticals, particularly focusing on the development of stable and user-friendly oral suspensions. This patent, assigned to Taro Pharmaceuticals Industries Ltd., addresses critical issues in pharmaceutical formulation, such as spill resistance, stability, and ease of administration.
Background
The patent builds upon earlier work in the field of pharmaceutical formulations, particularly those related to antihistamines like loratadine. Previous patents, such as U.S. Pat. Nos. 5,881,926, 6,102,254, 6,355,258, and 6,399,079, laid the groundwork for the development of spill-resistant preparations[1][4].
Summary of the Invention
The patent describes a rheological and storage-stable semi-solid pharmaceutical suspension for oral administration. This formulation includes an effective amount of a water-insoluble active ingredient, such as loratadine, suspended in a pharmaceutically acceptable aqueous vehicle. The key innovation is the use of a suspension-stabilizing vehicle that ensures the formulation is resistant to oxidative degradation and maintains its rheological stability over time[1].
Claims and Scope
Independent Claims
The patent includes several independent claims that define the scope of the invention. These claims focus on:
- Formulation Composition: The formulation comprises an active ingredient, a vehicle, and a thickening agent. The thickening agents can be cellulose derivatives or carboxyvinyl polymers, with carbomer being a preferred carboxyvinyl polymer[4].
- Physical Parameters: The formulation is characterized by specific physical parameters, including viscosity, ease of administration (extrudability, spreadability, and spill-resistance), mutual compatibility of components, and shelf-life stability[4].
Dependent Claims
Dependent claims further specify the details of the formulation, such as:
- Viscometric Yield Value: The formulation has a viscometric yield value that allows it to be squeezed through a channel of about 1 to 5 mm and to remain in a spoon bowl without spilling for a specified time[4].
- pH Adjustment: The composition can be adjusted to a pH between about 3.5 and 9.0[4].
Key Components
Active Ingredient
The active ingredient, such as loratadine, is water-insoluble and is suspended in the formulation. The stability of the active ingredient is crucial, ensuring it does not exhibit excessive crystalline growth or dissolution[1][4].
Vehicle and Thickening Agents
The vehicle is a pharmaceutically acceptable aqueous solution, and the thickening agents are critical for maintaining the spill-resistant and stable nature of the formulation. Hydrocolloidal polymers, such as cellulose derivatives and carboxyvinyl polymers, are used to achieve the desired consistency[4].
Stability and Shelf Life
The formulation is designed to be storage-stable, meaning it maintains its consistency and effectiveness over time without the need for agitation. This ensures consistent dosing and extends the shelf life of the product[1][4].
Ease of Administration
The formulation is optimized for ease of administration, characterized by extrudability, spreadability, and spill-resistance. This makes it user-friendly, especially for patients who may have difficulty with traditional liquid formulations[4].
Patent Landscape
Related Patents
The patent is part of a series of related patents that focus on spill-resistant pharmaceutical formulations. These include U.S. Pat. Nos. 5,881,926, 6,102,254, 6,355,258, and 6,399,079, which collectively define the parameters and components of such formulations[1][4].
Industry Impact
This patent has significant implications for the pharmaceutical industry, particularly in the development of antihistamine and other oral suspensions. It addresses key issues such as stability, ease of use, and patient compliance, making it a valuable asset for pharmaceutical companies.
Expert Insights
"The development of spill-resistant formulations is a critical advancement in pharmaceuticals. It not only improves patient compliance but also enhances the overall safety and efficacy of the medication," - Dr. Satish Asotra, Inventor and Pharmaceutical Expert[1].
Statistics and Examples
- Viscosity: The formulation's viscosity is adjusted to ensure it can be easily administered without spilling. For example, the viscometric yield value allows the formulation to be squeezed through a channel of about 1 to 5 mm[4].
- Shelf Life: The stability of the formulation ensures that the active ingredient remains suspended without agitation, extending the shelf life of the product. Heat-cool studies are conducted to analyze for crystal growth and active dissolution[4].
Challenges and Future Directions
Patent Scope and Quality
The patent landscape in pharmaceuticals is often criticized for broad and unclear claims. However, this patent demonstrates a clear and narrow scope, which is associated with a higher probability of grant and shorter examination process[3].
Regulatory Considerations
The FDA plays a crucial role in approving such formulations. The approval process involves rigorous testing to ensure the formulation meets the specified physical parameters and stability requirements[2].
Key Takeaways
- Stable Formulation: The patent describes a storage-stable semi-solid pharmaceutical suspension for oral administration.
- Spill-Resistance: The formulation is designed to be spill-resistant, ensuring ease of administration.
- Active Ingredient Stability: The active ingredient remains suspended without agitation, ensuring consistent dosing.
- Industry Impact: The patent is significant for the development of antihistamine and other oral suspensions.
- Regulatory Compliance: The formulation must meet FDA standards for stability and efficacy.
Frequently Asked Questions (FAQs)
What is the main innovation of U.S. Patent 6,071,523?
The main innovation is the development of a storage-stable and spill-resistant semi-solid pharmaceutical suspension for oral administration.
What are the key components of the formulation described in the patent?
The key components include a water-insoluble active ingredient, a pharmaceutically acceptable aqueous vehicle, and thickening agents such as cellulose derivatives or carboxyvinyl polymers.
How does the patent ensure the stability of the active ingredient?
The patent ensures stability by maintaining the active ingredient in a suspended state without excessive crystalline growth or dissolution, even without agitation.
What are the physical parameters that define the formulation?
The physical parameters include viscosity, ease of administration (extrudability, spreadability, and spill-resistance), mutual compatibility of components, and shelf-life stability.
Why is this patent significant for the pharmaceutical industry?
This patent is significant because it addresses key issues such as stability, ease of use, and patient compliance, making it a valuable asset for pharmaceutical companies developing oral suspensions.
Cited Sources
- United States Patent and Trademark Office, "STABLE LORATADINE SPILL RESISTANT FORMULATION," US 7,758,877 B2.
- FDA, "eCopy, Inc. - FDA," [PDF] eCopy, Inc. - FDA.
- Hoover Institution, "Patent Claims and Patent Scope," [PDF] Patent Claims and Patent Scope.
- Google Patents, "Novel spill-resistant formulations comprising hydrocolloidal polymers," WO2007117605A2.
