**Abstract**

Polyvinylpyrrolidone (PVP) has proven to be a highly versatile material, as evidenced by its long history as multifunctional biomaterial with a wide range of high-performance applications (e.g., tissue engineering, drug delivery systems, and ophthalmologic applications). PVP was frequently used in medical and pharmaceutical field due to its several interesting properties (higher glass transition temperature, water solubility, biocompatibility, biodegradability, chemical stability, very good adhesive, and emulsifying agent). This chapter highlights the multifunctional roles of PVP in pharmaceutical formulations in solid state. In fact, PVP acted as a stabilizing agent for various amorphous drug molecules by minimizing their molecular mobility. Physical stabilization resulted from the reinforcement of intermolecular interactions in binary or ternary systems due to the synergetic effect of PVP. This made it possible to overcome several challenges for drug formulations (e.g., solubility and bioavailability weakness, physical instability under stress conditions, complexation efficiency of cyclodextrin molecules). In this chapter, the effect of PVP on the binary solid dispersion (indomethacin:kaolin) is discussed. We have shown that PVP enhanced physical stability of amorphous indomethacin under stress conditions (at RH: 75% and T = 40°C for three months), leading to the improvement of drug aqueous solubility by suppressing kaolin adsorption effect.

**Keywords:** biomaterial, PVP, molecular mobility, physical stability, water solubility, solid dispersion, kaolin, indomethacin
