Preparation of drug microparticles with a narrow size distribution using regular dimples induced by buckling instability

Abstract

Particle size reduction is effective in increasing the dissolution rate and bioavailability of poorly water-soluble drugs. However, obtaining microparticles without a size distribution or even with a narrow size distribution is difficult with conventional methods, such as milling and antisolvent precipitation. In the novel method used in this study, uniformly sized droplets of a drug solution were first prepared on a polydimethylsiloxane film, and the film was dried thereafter to precipitate drug particles with a narrow size distribution. The uniformly sized droplets were prepared as follows: the surface of the polydimethylsiloxane film was first oxidized through UV-ozone treatment. The stress in the oxidized layer swollen with polar organic solvents caused buckling instability, which induced the formation of regular dimples. A method similar to dip coating was then used to produce uniform droplets in the dimples and prepare drug particles using salicin and nifedipine.