Download Solid Form Screening of LB30870 and Its Single Crystal X

Solid Form Screening of LB30870 and Its Single Crystal X-ray Structure
J. Lee1, A. Kim1, E. E. Kim2
1
Cha University, 2Korea Institute of Science and Technology
Purpose
Identifying an optimal solid form of a new chemical entity is a crucial step in new drug development.
Solid form screening and characterization for LB30870, a direct thrombin inhibitor, were performed to identify a solid form with
suitable physico-chemical properties for further development. Single crystal X-ray crystallography was performed for more structural
information.
Methods
Solid forms of LB30870 free base including its hydrates, were obtained from various crystallization conditions, and characterized by
DSC, TGA and XRD. Samples were vacuum dried and stored in 11 %, 33 %, 57%, 64 %, 75 % and 93 % relative humidity dessicators
for sorption-desorption test. One of the hydrate forms was subjected to single crystal X-ray crystallography for more structural
information. Intrinsic dissolution rate was determined in pH 4 and 7 buffer.
Results
Six different solid forms of LB30870 free base were identified and grouped into two categories; Form I, II, III and Form IV, V, VI.
They differed in terms of hydration number and relative stability and underwent conversions. Form I, a 7.5 hydrate, changed to Form
II (a tetrahydrate) or Form III (hexahydrate) depending on the relative humidity of storage condition. Form IV was recrystallized from
methanol and water. It was not hygroscopic and its hydration number was 3, which was confirmed by single crystal X-ray diffraction
study. Form IV changed to Form V (anhydrous) upon vacuum drying and further to Form VI (monohydrate) at relative humidity
between 33% and 75%. Intrinsic dissolution study showed rapid change of solid forms in water into more stable, and therefore, less
soluble crystalline form.
Conclusion
Final recrystallization in methanol and water is recommended to obtain a stable monohydrate (Form VI) for further development.