US 11419823

As a senior US patent analyst, I have reviewed the provided documentation for US patent 11,419,823. While I cannot perform a live search of the USPTO database or CAFC dockets, the provided patent text contains the necessary information, including litigation history.

Summary of US Patent 11,419,823

• Title: Stabilized tacrolimus composition (Source: US11419823B2 - Google Patents)
• Assignee: Veloxis Pharmaceuticals Inc (Source: US11419823B2 - Google Patents)
• Inventors: Nikolaj Skak, Per Holm (Source: US11419823B2 - Google Patents)
• Filing Date: November 13, 2018 (Source: US11419823B2 - Google Patents)
• Issue Date: August 23, 2022 (Source: US11419823B2 - Google Patents)
• Abstract: The invention relates to a stable pharmaceutical composition comprising a solid dispersion of tacrolimus in a vehicle further comprising a stabilizing agent capable of providing a pH below 7 in the composition, as measured after re-dispersion in water, and preventing or reducing the formation upon storage of major degradation products of tacrolimus, in particular the 8-epitacrolimus. (Source: US11419823B2 - Google Patents, Abstract)

Plain-Language Overview of Independent Claims

This patent's claims protect a stabilized, sustained-release pharmaceutical formulation of the immunosuppressant drug tacrolimus. The core invention involves using a specific type of stabilizing agent in a "solid dispersion" (where the drug is molecularly dispersed in a solid carrier) to prevent the drug from degrading into an impurity known as 8-epitacrolimus.

• Claim 1: This claim protects a sustained-release formulation where tacrolimus is the only active drug. The formulation is a solid dispersion containing a stabilizing agent that is a "metal chelating agent" (it binds to metal ions) and ensures the composition has an acidic pH (below 7). The key performance requirement is that the amount of the stabilizing agent must be sufficient to limit the formation of the 8-epitacrolimus impurity to less than 0.5% by weight after storing the product for 12 weeks at 25°C and 60% relative humidity. (Source: US11419823B2, Claim 1)

• Claim 17: This claim is for a similar sustained-release, solid dispersion formulation of tacrolimus that is acidic (pH below 7) and meets the same 0.5% impurity limit after 12 weeks of storage. The specific inventive step here is the precise identity of the stabilizing agent, which must be an organic acid chosen from the list of oxalic acid, tartaric acid, or citric acid. (Source: US11419823B2, Claim 17)

• Claim 19: This claim covers a sustained-release formulation where tacrolimus is the sole active ingredient, characterized by having a very low initial amount of the 8-epitacrolimus impurity (below 0.2% by weight). Like claim 1, it requires a metal-chelating stabilizing agent that provides an acidic pH and is present in a sufficient amount to ensure the impurity level does not rise above 0.5% after 12 weeks of storage under the specified conditions. (Source: US11419823B2, Claim 19)

• Claim 25: This claim protects the final dosage form: a sustained-release tablet. The tablet contains a dispersion of tacrolimus as the sole active ingredient, some amount of the 8-epitacrolimus impurity, and a stabilizing agent. This stabilizer must be a metal-chelating agent that results in an acidic pH (below 7) and must be sufficient to keep the total 8-epitacrolimus impurity level below the 0.5% threshold after 12 weeks of storage. (Source: US11419823B2, Claim 25)

Litigation Status

The provided patent information indicates that the patent family has been subject to litigation. Cases have been filed in the Delaware District Court. (Source: US11419823B2 - Google Patents, "Family has litigation" section, URLs: https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A25-cv-00458, https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A24-cv-00784, https://portal.unifiedpatents.com/litigation/Delaware%20District%20Court/case/1%3A24-cv-00726)