Nanoemulsions produced by rotor-stator high speed stirring.

Nanoemulsions were produced by high speed stirring using an ART MICCRA D27 rotor-stator system. Nanoemulsions with a droplet size of 135 nm and a narrow size distribution were obtained. The emulsions are physically stable for at least three months. Optimized production parameters are a stirring speed of 36,000 rpm (maximum speed) and a production time of 5 min. A further reduction in processing time might be possible with a rotor with ultrafine slit size, i.e., 0.5 mm. The droplet size of the emulsion produced by high speed stirring is slightly larger than droplet sizes obtained by high pressure homogenization. However, the differences in size can be expected to have no influence on the in vivo efficacy of the emulsions. Thus, high speed stirring was found to be a highly effective method for the production of nanoemulsions. The process is fast, cost-effective and can be used for large scale production.