A Combined Isolation and Formulation Approach to Convert Nanomilled Suspensions into High Drug-Loaded Composite Particles That Readily Reconstitute

Abstract

The advantage of nanoparticles to improve bioavailability of poorly soluble drugs is well known. However, the higher-energy state of nanoparticles beneficial for bioavailability presents challenges for both the stability of nanosuspensions and preventing irreversible aggregation if isolated as dry solids. The aim of this study is to explore the feasibility of an evaporation isolation route for converting wet media milled nanosuspensions into high drug-loaded nanocomposites that exhibit fast redispersion in aqueous media, ideally fully restoring the particle size distribution of the starting suspension. Optimization of this approach is presented, starting from nanomilling conditions and formulation composition to achieve physical stability post milling, followed by novel evaporative drying conditions coupled with various dispersant types/loadings. Ultimately, isolated nanocomposite particles reaching 55–75% drug load were achieved, which delivered fast redispersion and immediate release of nanoparticles when the rotary evaporator drying approach was coupled with higher concentration of hydrophilic polymers/excipients. This bench-scale rotary evaporation approach serves to identify optimal nanoparticle compositions and has a line of sight to larger scale evaporative isolation processes for preparation of solid nanocomposites particles.