Is PVP K-29/32 an Efficient Stabilizing Excipient in Amorphous Solid Dispersions Containing the Poorly Water-Soluble Drug—Bicalutamide?

The stability of amorphous drug substances is a crucial issue in the pharmaceutical field. This study examines the influence of polyvinylpyrrolidone as an excipient on the stabilization of the amorphous drug substance bicalutamide. Solid dispersions of the active substance and the excipient were prepared in different weight ratios using ball milling, then packed into aluminum sachets and stored in a climate chamber for one year. The results indicate successful amorphization of bicalutamide, as confirmed by the absence of crystalline structure in the diffractograms and improved dissolution in the 1:1, 2:1, and 4:1 weight ratio systems. However, the 10:1 drug-to-excipient composition remained crystalline. Our findings demonstrate that PVP effectively stabilizes bicalutamide in its amorphous form. The solid dispersions prepared in weight ratios ranging from 1:1 to 4:1 remained stable under both tested storage conditions throughout the entire study period.