Production Techniques - Lipid Nanoparticles: Production, Characterization and Stability - page 22

Chapter 3
Production Techniques

Abstract Besides composition and structure, an important factor which influ-
ences the performance and characteristics of lipid nanoparticles is their produc-
tion method, and a variety of production techniques have been introduced since
the inception of lipid nanoparticles as potential colloidal carriers. The production
techniques can be categorized into two groups; techniques which require high
energy for dispersion of the lipid phase (such as high pressure homogenization,
high sheer homogenization, ultrasonication) and techniques which require precipi-
tation of nanoparticles from homogenous systems (such as microemulsions, sol-
vent-based techniques, membrane contactors and coacervation). The choice of an
appropriate technique is based on the physicochemical properties of the drug, the
physicochemical characteristics and stability of the colloidal formulation and the
availability of equipment. This chapter gives an overview of the techniques used in
the production of lipid nanoparticle dispersions and also provides a brief introduc-
tion to a novel technique based on the use of microwave energy developed by our
group.

Keywords Production · Homogenization · Microemulsion · Solvent-based ·
Coacervation · Membrane contactor · Microwave

3.1 General Considerations

Several approaches for the preparation of lipid nanoparticle dispersions have been
reported since these carriers were first described in early 1990s (Gasco 1993 ;
Schwarz et al. 1994 ; Siekmann and Westesen 1992 ). The preparation technique
has a significant role in the performance of the colloidal formulation. The choice
of preparation technique for lipid nanoparticle dispersions may be influenced by:

• Physicochemical properties of the drug to be incorporated
• Stability of the drug to be incorporated
• Desired particle characteristics of the lipid nanoparticle dispersion