Hydrocodone base and methods for its purification
Inventors
Cardot, Jessica • SASINE, JOSHUA • Nichols, Paul
Assignees
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Publication Number
US-11155548-B2
Publication Date
2021-10-26
Expiration Date
Abstract
A method of recovering a highly pure hydrocodone base from an impure hydrocodone preparation includes contacting the impure hydrocodone preparation with a weak acid in water to form a solution and adding a strong base to the solution in an amount sufficient to precipitate the pure hydrocodone base product. A highly pure hydrocodone base comprises less than 0.0025 wt % codeinone.
Core Innovation
The invention relates to a method of recovering a highly pure hydrocodone base from an impure hydrocodone preparation. The method comprises contacting the impure hydrocodone preparation with a weak acid in water to form a solution, and then charging the solution with an organic solvent before the addition of a strong base.
After charging the solution with the organic solvent, a strong base is added in an amount sufficient to precipitate the highly pure hydrocodone base. The approach is presented as reducing impurities in the hydrocodone base product, including reduction of codeinone, and as achieving target purity measured by HPLC.
The document also describes representative weak acids and strong bases, optional pH conditions for the weak-acid and basic precipitation stages, and alcohol co-solvents in relation to improved impurity reduction. Comparative performance is described versus stronger acid processing, and scale-up/confirmation batches are described with low levels of codeinone and related impurities after processing.
Claims Coverage
The independent claim covers a precipitation-based recovery of highly pure hydrocodone base using a weak-acid aqueous solution followed by organic-solvent charging and strong-base precipitation. The inventive subject matter includes three main inventive features, as recited in the independent claim.
Weak-acid aqueous solution formation from an impure hydrocodone preparation
Contacting the impure hydrocodone preparation with a weak acid in water to form a solution.
Organic solvent charging before strong-base addition
Charging the solution with an organic solvent before the addition of the strong base.
Strong-base precipitation to recover a highly pure hydrocodone base
Adding a strong base to the solution in an amount sufficient to precipitate the highly pure hydrocodone base.
Across the dependent claims mentioned, the independent-claim framework is refined by specifying the organic solvent as an alcohol with enumerated options and by characterizing the recovered highly pure hydrocodone base using quantitative impurity limits, including codeinone and 6α-tetrahydrothebaine, and an HPLC purity target.
Stated Advantages
Improved impurity reduction, including reduction of codeinone.
Recovery of highly pure hydrocodone base with a cited high purity level measured by HPLC (e.g., 99.9% area).
Low levels of codeinone and related impurities in scale-up/confirmation batches.
Documented Applications
Recovering a highly pure hydrocodone base from an impure hydrocodone preparation using weak-acid formation of an aqueous solution, organic-solvent charging, and strong-base precipitation.
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