Novel anhydrous solid-state form of Azathioprine: The assessing of crystal structure by powder X-Ray diffraction, Infrared Absorption Spectroscopy and Raman scattering

A peculiar dehydration and solid–solid phase transition of the active pharmaceutical ingredient AZD9898 based on in situ single crystal-to-single crystal transformations

“…In the most cases, single crystals of the initially hydrated phase begin to lose integrity and transform to a polycrystalline phase; structure determination using powder methods are therefore usually employed to establish the dehydration mechanism of hydrated APIs. [20][21][22][23][24] . Systems where the hydrated phase retains its single-crystallinity upon dehydration are more experimentally challenging.…”

Photodegradation of Azathioprine in the Presence of Sodium Thiosulfate

“…The reaction of AZA with ST induced the following changes in the Raman spectra of the two compounds: (i) an upshift of the Raman lines of AZA in the 1460–1550 cm −1 spectral range; (ii) a change in the intensity ratio of the Raman lines peaking at 1305 cm −1 and 1330 cm −1 (I 1305 /I 1330 ) from 3.45 (AZA) [ 12 ] to 4.35 (AZA:ST 75 wt.%: 25 wt.% sample), 4.11 (AZA:ST 50 wt.%: 50 wt.% sample) and 4.57 (AZA:ST 25 wt.%: 75 wt.% sample); and (iii) a change in the intensity ratio of the ST Raman lines at 436 cm −1 and 455 cm −1 (I 436 /I 455 ) from 4.13 in ST to 0.9 (AZA:ST 75 wt.%: 25 wt.% sample), 1.7 (AZA:ST 50 wt.%: 50 wt.% sample) and 1.96 (AZA:ST 25 wt.%: 75 wt.% sample). The variation in the I 1305 /I 1330 ratio shows that the chemical reaction of AZA with ST induces changes in the purine ring.…”

“…Once in the body, AZA is converted to mercaptopurine, a compound belonging to the class of purines, which will eliminate the effect of some cells in the body’s immune system [ 6 ], which may increase the probability of developing an infection [ 7 ]. However, many techniques for the determination of AZA both in pharmaceutical formulations and in biological fluids, such as cyclic voltammetry [ 8 ], high-performance liquid chromatography [ 9 ], flow injection chemiluminescence [ 10 ], 1 H NMR spectroscopy [ 11 ], FT-IR spectroscopy [ 12 ], Raman scattering [ 12 ], surface-enhanced Raman scattering [ 13 ] and UV-VIS absorption spectroscopy, ref. [ 14 ] have been used.…”

Isomorphic Channel-Type Pseudopolymorphs of Azathioprine: From Structural Confirmations to a Rational Polymorph Screening Approach

“…The main objective in working with commercial AZA Form I was to conduct a comprehensive polymorph screen program on the API that included both kinetically and thermodynamically controlled experiments. Prior to the date, AZA Form I was also characterized by using various analytical methods, , with the purpose of collecting the reference analytical data of the material used for polymorph screen program.…”

“…Based on the solubility data and physicochemical properties of AZA Form I, , a comprehensive polymorph screening was designed in which both kinetically (e.g., reverse and forward antisolvent addition, crash cooling and fast evaporation) and thermodynamically (e.g., slurry, solvent drop grinding, antisolvent diffusion onto solutions and solids and slow evaporation experiments) controlled experiments were included. A detailed description of the pseudopolymorphs is presented in Table S1 in the ESI.…”