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Concomitant pseudopolymorphs of 10-deacetyl baccatin III
Lakshmi Kumar Tatini1, N Someswara Rao, Muzaffar Khan
1Analytical Development, Aptuit Laurus Pvt. Ltd, ICICI Knowledge Park, Turkapally, Shameerpet, Hyderabad 500078, India. kumarltatini@gmail.com
AAPS Pharmscitech
|March 14, 2013
Summary
Three new solvates of 10-Deacetyl baccatin III were synthesized using various solvents, including dimethyl sulfoxide (DMSO), dimethyl acetamide (DMA), and dimethyl formamide (DMF). Characterization revealed host-guest interactions via hydrogen bonds and distinct desolvation temperatures for different solvate forms.
Area of Science:
- Solid-state chemistry
- Crystallography
- Organic chemistry
Background:
- 10-Deacetyl baccatin III is a crucial intermediate in the synthesis of paclitaxel and its analogues.
- Solvate formation can significantly influence the physicochemical properties and bioavailability of drug molecules.
- Understanding solvate structures is essential for optimizing drug development and manufacturing processes.
Purpose of the Study:
- To synthesize and characterize new solvates of 10-Deacetyl baccatin III.
- To investigate the structural features and intermolecular interactions within these solvates.
- To analyze the thermal properties, specifically desolvation behavior, of the newly formed solvates.
Main Methods:
- Solvate synthesis via slow evaporation in various solvent systems (DMSO, DMF, DMSO/DMA).
- Characterization using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA).
- Spectroscopic analysis including (13)C solid-state NMR, (1)H NMR, and Fourier transform infrared (FTIR) spectroscopy.
- Structural elucidation of host-guest interactions using single-crystal X-ray diffraction.
Main Results:
- Three new solvates were successfully synthesized: mono-dimethyl sulfoxide (mono-DMSO), mono-dimethyl acetamide (mono-DMA), and mono-dimethyl formamide (mono-DMF).
- Concomitant forms, including known di-DMSO solvates, were observed in DMSO and DMSO/DMA solvent systems.
- Single-crystal X-ray diffraction confirmed O-H∙∙∙O hydrogen bonds between host (10-Deacetyl baccatin III) and guest (solvent) molecules.
- Significant differences in desolvation onset temperatures were observed between di- and mono-DMSO solvates, correlating with TGA weight loss.
Conclusions:
- New solvates of 10-Deacetyl baccatin III have been successfully prepared and characterized, expanding the known crystalline forms.
- The study elucidates the role of hydrogen bonding in stabilizing these solvate structures.
- Thermal analysis reveals distinct desolvation profiles, highlighting the impact of solvation number on thermal stability.
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