Preparation of stable colloidal suspensions of superdisintegrants via wet stirred media milling

Abstract Superdisintegrants are cross-linked polymers that can be used as dispersants for fast release of drug nanoparticles from nanocomposite microparticles during in vitro and in vivo dissolution. Currently available superdisintegrant particles have average sizes of approximately 5–130 μm, which are too big for drug nanocomposite applications. Hence, production of stable superdisintegrant suspensions with less than 5 μm particles is desirable. Here, we explore the preparation of colloidal suspensions of anionic and nonionic superdisintegrants using a wet stirred media mill and assess their physical stability. Sodium starch glycolate (SSG) and crospovidone (CP) were selected as representative anionic and nonionic superdisintegrants, and hydroxypropyl cellulose (HPC) and sodium dodecyl sulfate (SDS) were used as a steric stabilizer and a wetting agent/stabilizer, respectively. Particle sizing, scanning electron microscopy, and zeta potential measurements were used to characterize the suspensions. Colloidal superdisintegrant suspensions were prepared reproducibly. The extensive particle breakage was attributed to the swelling-induced softening in water. SSG suspensions were stable even in the absence of stabilizers, whereas CP suspensions required HPC–SDS for minimizing particle aggregation. These findings were explained by the higher absolute (negative) zeta potential of the suspensions of the anionic superdisintegrant (SSG) as compared with those of the nonionic superdisintegrant (CP).