United States Patent 6,333,045: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
The United States Patent 6,333,045, titled "Aqueous Liquid Pharmaceutical Composition Comprised of Gatifloxacin," was issued on December 25, 2001, to inventors Shinichi Yasueda and Katsuhiro Inada, and assigned to Senju Pharmaceutical Co., Ltd. and Kyorin Pharmaceutical Co., Ltd. This patent is significant in the pharmaceutical industry, particularly for formulations involving the antibiotic gatifloxacin.
Background of Gatifloxacin
Gatifloxacin is a quinolone carboxylic acid derivative, chemically known as (+)-1-cyclopropyl-6-fluoro-1,4-dihydro-8-methoxy-7-(3-methyl-1-piperazinyl)-4-oxo-3-quinoline carboxylic acid. It is used in various pharmaceutical applications, including eye, ear, and nasal drops, due to its antimicrobial properties[1].
Scope of the Patent
The patent covers an aqueous liquid pharmaceutical composition that includes gatifloxacin or its salt as the main component. Here are the key aspects of the scope:
Composition Components
- The composition includes gatifloxacin or its salt.
- It may contain various additives such as glycerin, propylene glycol, mannitol, sorbitol, and glucose.
- Buffer solutions like phosphate, acetate, borate, citrate, glutamic acid, and e-aminocapronic acid can be included.
- Preservatives such as benzalkonium chloride, benzethonium chloride, and chlorhexidine gluconate are also part of the formulation.
- Thickening agents like methylcellulose, hydroxyethyl cellulose, and carboxymethylcellulose can be used[1].
pH Range
The pH of the composition is specified to be within the range of 5 to 8, which is crucial for maintaining the stability and efficacy of gatifloxacin[4].
Claims of the Patent
The patent includes 11 claims, with the following being the most relevant:
Claim 1
- An aqueous liquid pharmaceutical composition comprising gatifloxacin or its salt and disodium edetate[4].
Claim 2
- The composition according to claim 1, where the pH is within the range of 5 to 8[4].
Claim 3
- The composition according to claim 1, where the composition is in the form of eye drops[4].
Claim 6
- A method for raising corneal permeability of gatifloxacin by incorporating disodium edetate into eye drops containing gatifloxacin or its salt[4].
Claim 7
- A method for preventing precipitation of gatifloxacin crystals by incorporating disodium edetate into an aqueous liquid preparation containing gatifloxacin or its salt[4].
Claim 8
- A method for preventing coloration of gatifloxacin by incorporating disodium edetate into an aqueous liquid preparation containing gatifloxacin or its salt[4].
Patent Landscape and Litigation
The patent has been involved in several legal disputes, particularly regarding infringement and validity.
Infringement Actions
In one notable case, Senju Pharmaceutical Co., Ltd. and Kyorin Pharmaceutical Co., Ltd. brought an infringement action against Apotex Inc., alleging that Apotex's ANDA (Abbreviated New Drug Application) product would infringe claims 1-3, 6, 7, and 9 of the '045 patent. The defendants stipulated that, if the patent was found valid, their product would infringe claims 1-3 and 9. However, they disputed the infringement of claims 6 and 7[4].
Validity Challenges
The validity of the patent was challenged in court, with the defendants arguing that the claims were obvious and therefore invalid. After a bench trial, the District Court concluded that the asserted claims from the '045 patent were invalid as obvious, securing a judgment of patent invalidity for the defendants[5].
Role of Disodium Edetate
Disodium edetate plays a crucial role in the patent claims. It is used to:
- Prevent Precipitation: Incorporating disodium edetate prevents the precipitation of gatifloxacin crystals in the aqueous solution[1][4].
- Prevent Coloration: It also prevents the coloration of gatifloxacin, ensuring the stability and appearance of the pharmaceutical composition[1][4].
- Enhance Corneal Permeability: Disodium edetate is used to increase the corneal permeability of gatifloxacin when used in eye drops[4].
Patent Analytics and Claim Coverage
To manage and analyze the patent landscape effectively, companies use patent analytics tools. These tools help in categorizing patents by claims and scope concepts, making it easier to identify gaps or opportunities in intellectual property protection.
- Claim Coverage Matrix: This tool shows which patents and claims are actively protecting the intellectual property and where gaps or opportunities exist[3].
- Claim Charts: Interactive claim charts generated by software like ClaimScape® help in reviewing patent coverage with technical experts, determining the applicability of scope concepts to target products or methods, and identifying future design opportunities[3].
Key Takeaways
- The patent covers aqueous liquid pharmaceutical compositions containing gatifloxacin or its salt, with specific formulations and additives.
- Disodium edetate is a critical component for preventing precipitation, coloration, and enhancing corneal permeability.
- The patent has been involved in significant litigation regarding infringement and validity.
- Patent analytics tools are essential for managing and analyzing the patent landscape.
FAQs
What is the main component of the pharmaceutical composition described in US Patent 6,333,045?
The main component is gatifloxacin or its salt.
What role does disodium edetate play in the patent claims?
Disodium edetate prevents the precipitation of gatifloxacin crystals, prevents coloration of gatifloxacin, and enhances corneal permeability when used in eye drops.
Which companies were involved in the litigation regarding this patent?
Senju Pharmaceutical Co., Ltd., Kyorin Pharmaceutical Co., Ltd., and Apotex Inc. were involved in the litigation.
What was the outcome of the validity challenge to the patent?
The District Court concluded that the asserted claims from the '045 patent were invalid as obvious.
How can companies effectively manage and analyze their patent landscape?
Companies can use patent analytics tools such as Claim Coverage Matrix and Claim Charts to categorize patents by claims and scope concepts, identifying gaps or opportunities in intellectual property protection.
Sources
- United States Patent and Trademark Office. (2001). Aqueous Liquid Pharmaceutical Composition Comprised of Gatifloxacin. US 6,333,045 B1.
- Wiley. Federal Circuit Patent Bulletin: Senju Pharm. Co. v. Apotex Inc..
- Schwegman Lundberg & Woessner, P.A.. Patent Analytics.
- District of Delaware. (2010). Senju Pharmaceutical Co., Ltd. v. Apotex Inc..
- RMMS Legal. RMMS Secures Judgment Of Patent Invalidity After A Trial Involving Gatifloxacin Ocular Formulation And Method.
