TY - JOUR

T1 - Influence of Crystal Packing on the Mechanism of Decomposition of the Acetonitrile-Solvated Cocrystal of Piroxicam and Succinic Acid

AU - Liu, Xiaojiao

AU - Tang, Chiu C.

AU - Boldyreva, Elena V.

AU - Pulham, Colin R.

PY - 2019/12

Y1 - 2019/12

N2 - Variable-temperature single-crystal and powder X-ray diffraction techniques have been used to study the thermal and mechanical decomposition of the acetonitrile solvate of the cocrystal formed between piroxicam and succinic acid (PRXSA-ACN). The results show that the thermal expansion behavior of PRXSA-ACN is highly anisotropic and can be correlated with the crystal structure. Thermally induced desolvation of PRXSA-ACN led initially to the formation of the α-form of piroxicam and the 1:1 piroxicam/succinic acid cocrystal (PRXSA), and this can be rationalized on the basis of the crystal structure of PRXSA-ACN and its thermal expansion behavior. Subsequent decomposition of PRXSA produced amorphous succinic acid and the thermodynamically more stable β-form of piroxicam. The α- and β-forms coexisted up to the melting of the α-form, at which point the sample recrystallized to give the β-form of piroxicam. Mechanical treatment (light grinding) of PRXSA-ACN resulted in mild structural damage to the crystallinity, and this led to subsequent desolvation.

AB - Variable-temperature single-crystal and powder X-ray diffraction techniques have been used to study the thermal and mechanical decomposition of the acetonitrile solvate of the cocrystal formed between piroxicam and succinic acid (PRXSA-ACN). The results show that the thermal expansion behavior of PRXSA-ACN is highly anisotropic and can be correlated with the crystal structure. Thermally induced desolvation of PRXSA-ACN led initially to the formation of the α-form of piroxicam and the 1:1 piroxicam/succinic acid cocrystal (PRXSA), and this can be rationalized on the basis of the crystal structure of PRXSA-ACN and its thermal expansion behavior. Subsequent decomposition of PRXSA produced amorphous succinic acid and the thermodynamically more stable β-form of piroxicam. The α- and β-forms coexisted up to the melting of the α-form, at which point the sample recrystallized to give the β-form of piroxicam. Mechanical treatment (light grinding) of PRXSA-ACN resulted in mild structural damage to the crystallinity, and this led to subsequent desolvation.

KW - CRYSTALLIZATION

KW - POLYMORPHS

KW - MONOHYDRATE

KW - PHASE

KW - WATER

UR - http://www.scopus.com/inward/record.url?scp=85075680329&partnerID=8YFLogxK

U2 - 10.1021/acs.cgd.9b01189

DO - 10.1021/acs.cgd.9b01189

M3 - Article

AN - SCOPUS:85075680329

VL - 19

SP - 7315

EP - 7323

JO - Crystal Growth and Design

JF - Crystal Growth and Design

SN - 1528-7483

IS - 12

ER -