Determining degradation of 3,4-diaminopyridine
Inventors
Schiehser, Guy Alan • Shah, Rajendra • Zhao, Wenyi
Assignees
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Publication Number
US-10626088-B2
Publication Date
2020-04-21
Expiration Date
Abstract
The present invention relates to methods of determining the purity of a sample of 3,4-diaminopyridine comprising determining the presence, absence, or amount of a dimer of 3,4-diaminopyridine or a dimer of 3,4-diaminopyridine in the form of a salt, solvate or complex or a combination thereof. The invention also relates to methods of detecting and quantitating degradation in a sample of 3,4-diaminopyridine. Dimers of 3,4-diaminopyridine and methods of making and isolating the same are also provided.
Core Innovation
The invention relates to a 3,4-diaminopyridine dimer that is or includes a tautomer thereof, provided in the form of a salt, solvate, or complex, or a combination thereof. The disclosed forms include salt, solvate, and complex embodiments, including pH-dependent forms and quaternary salt behavior.
A degradation-associated 3,4-diaminopyridine dimer is used as a degradation marker, including salt, solvate, and complex forms. The degradation is assessed and quantitated by detecting the degradation-associated 3,4-diaminopyridine dimer using HPLC peak identification and comparison to a dimer standard.
The disclosure further provides a marker composition of 3,4-diaminopyridine dimer sulfate monohydrate monomethanolate and describes analytical and structural characterization of the marker. Characterization includes single-crystal X-ray diffraction and XRPD, together with hydrogen-bonding and packing information, including a described space group.
Claims Coverage
The independent claim covers a 3,4-diaminopyridine dimer, or a tautomer thereof, in the form of a salt, solvate, or complex, including combinations thereof. The inventive features are centered on the specified molecular identity and the specified solid-state presentations, with dependent claims narrowing to specific sulfate, monohydrate, and monomethanolate forms and to an amorphous solid form.
3,4-diaminopyridine dimer tautomer in a salt, solvate, or complex
A 3,4-diaminopyridine dimer that is or includes a tautomer thereof, wherein the dimer is in the form of a salt, solvate, or complex, or a combination thereof.
Sulfate salt of the 3,4-diaminopyridine dimer
The 3,4-diaminopyridine dimer salt includes a sulfate group.
Monohydrate complex of the 3,4-diaminopyridine dimer
A 3,4-diaminopyridine dimer complex that includes a monohydrate group.
Solvate containing a monomethanolate group
The 3,4-diaminopyridine dimer is provided as a solvate containing a monomethanolate group.
3,4-diaminopyridine dimer sulfate monohydrate monomethanolate form
The 3,4-diaminopyridine dimer is the sulfate monohydrate monomethanolate form.
Amorphous solid form of the 3,4-diaminopyridine dimer sulfate monohydrate monomethanolate
The dimer is in an amorphous solid form.
Overall claim coverage is directed to the 3,4-diaminopyridine dimer, including a tautomer, and its solid-state forms, beginning with general salt, solvate, and complex presentations and narrowing to specific sulfate and inclusion groups. The claims further restrict the invention to the named marker form 3,4-diaminopyridine dimer sulfate monohydrate monomethanolate and optionally to an amorphous solid form.
Stated Advantages
Enables assessment and quantitation of degradation of 3,4-diaminopyridine by detecting a degradation-associated 3,4-diaminopyridine dimer using HPLC peak identification and comparison to a dimer standard.
Documented Applications
Use as a degradation marker to assess and quantitate degradation of 3,4-diaminopyridine by HPLC detection and comparison to a dimer standard.
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