Influence of the Formulation for Solid Lipid Nanoparticles Prepared with a Membrane Contactor

Solid lipid nanoparticles (SLN) were introduced in the 1990s as an alternative to microemulsions, polymeric nanoparticles, and liposomes. The SLN are reported to have several advantages, i.e., their biocompatibility and their controlled and targeted drug release. In this paper, we present a new process for the preparation of SLN using a membrane contactor to allow large scale production. The lipid phase is pressed, at a temperature above the melting point of the lipid, through the membrane pores allowing the formation of small droplets. The lipid droplets are then detached from the membrane pores by the aqueous phase flowing tangentially to the membrane surface. The SLN are formed by the following cooling of the preparation below the lipid melting point. The influence of the aqueous phase and lipid phase formulations on the lipid phase flux and on the SLN size are studied. It is shown that SLN are obtained with a lipid phase flux between 0.21 and 0.27 m^3/h.m², SLN size between 175 and 260 nm. The advantages of this new process are demonstrated to be its facility of use and its scaling-up ability.