Nano- and micro-particulate formulations of poorly water-soluble drugs by using a novel optimized technique.

A novel technique for the production of nano- and micro-particulate formulations of poorly water-soluble drugs has been developed. This technique involves the use of static mixer elements to provide fast precipitation by continuous turbulent mixing of two liquid flows, an aqueous phase and an organic phase, respectively. The objective of this study was to develop the mixer technique by investigating the influence of the element number on the particle size of the resulting dispersions. Four model active pharmaceutical ingredients (APIs) with a variety of polymers, lipids or surfactants underwent intensive mixing and the final suspensions showed a narrow size distribution. Parameters such as the flow rate and the temperature of the precipitated organic-aqueous phases were also significant in the reduction of particle size. Further development of the mixing technique led to reproducible and stable formulations with minimal excipient amounts. These formulations were spray- or freeze-dried to improve stability.