Fabrication of multicomponent amorphous bufadienolides nanosuspension with wet milling improves dissolution and stability.

Multicomponent formulations have attracted increasing attention because of their favourable patient compliance and greater therapeutic effect. The aim of this study was to develop a multicomponent nanosuspension formulation of bufadienolides, the antitumor components of a traditional Chinese medicine, toad venom, using a wet-milling technique to improve its dissolution behaviour. Croscarmellose sodium (CCS) and sodium lauryl sulfate (SLS) were chosen as the combined stabilizers of the nanosuspension. A Taguchi orthogonal array design was used for this study to optimize the formulation and process parameters. The optimized nanosuspension was characterized by its particle size distribution, zeta potential, morphology, crystallinity, molecular interactions, stability and dissolution. The results showed that the nanosuspension was a homogeneous amorphous system with average particle sizes of <100 nm and significantly improved dissolution behaviour. It was also physically stable for at least 2 months; steric and kinetic stabilization were its main stability mechanisms. These findings suggested that the use of wet milling to fabricate nanosuspensions is a promising method for achieving the fast and synchronized dissolution of multicomponent formulations, presumably increasing the bioavailability of poorly water-soluble drugs.