Pharmaceutical polymorphism of a 5´-O-oxalatoyl prodrug of zidovudine (azidothymidine)

D. KASSUHA; F. P. BRUNO; G. A. MONTI; N. R. SPERANDEO

Journal of Applied Pharmaceutical Science

Open Science Publishers LLP

Año: 2020 vol. 10 p. 67 - 67

he importance of polymorphism in pharmaceuticals makes its study relevant. The aim of this study was to investigate the solid-state forms in which 3´-azido-2´,3´-dideoxi-5´-O-oxalatoyl-thymidinic acid (AZT-Ac), a zidovudine (AZT) prodrug with improved pharmacokinetic properties, may exist. Samples were prepared using different crystallization conditions, and characterized using powder X-ray diffraction, solid state nuclear magnetic resonance, differential scanning calorimetry, thermogravimetry and hot stage microscopy. Pharmaceutical relevant properties such as solid-state stability and intrinsic dissolution rate (IDR) at 37 °C in simulated gastric fluid (SGF) were also evaluated. AZT-Ac was found able to exist as a crystalline polymorph (AZT-Ac-C) and an amorphous phase (AZT-Ac-A), which were thoroughly characterized. At 40 °C/75% RH, AZT-Ac-A in part devitrified to AZT-Ac-C, and partially hydrolyzed to AZT after 7 and 14 days of storage, respectively. AZT-Ac-C was physically