Lipid-core nanocapsules: mechanism of self-assembly, control of size and loading capacity

Nanotechnology in pharmaceutics has the potential to improve drug efficacy by influencing drug distribution in tissues. Nanocarriers have been developed as drug delivery systems to be administered by different biological routes. To ensure the nanotechnological properties, pre-formulation studies are especially critical in determining the influence of the process parameters on the size and polydispersity of particles. Thus, the objective of this work was to establish the mechanism of self-assembly, by determining the influence of the critical aggregation concentration of the materials in the organic phase on the final average particle size and polydispersity of polymeric lipid-core nanocapsules obtained by interfacial deposition of polymer. Measurements of the surface tension and viscosity of the organic and aqueous phases were correlated with the particle size and the concentration of raw materials. We demonstrated that the lipid-core nanocapsules are formed on the nanoscopic scale as unimodal distributions, if the aggregation state of raw materials in the organic phase tends to infinite dilution. The strategy for controlling the particle size distribution is a valuable tool in producing lipid-core nanocapsule formulations with different loading capacities intended for therapeutics.