Introduction - Lipid Nanoparticles: Production, Characterization and Stability - page 1

Chapter 1
Introduction

Abstract Highly potent, but poorly water-soluble, drug candidates are common
outcomes of lead optimization and other such drug discovery programmes. Poor
drug solubility presents several challenges including reduced bioavailability on
oral administration, lack of fed-fasted equivalence and abandonment of drug mol-
ecules in the early stage of development. Amongst many different strategies for
improving drug solubility (e.g. micronization, complexation, prodrug design etc.),
development of colloidal carriers has been looked upon as a favourable strategy. A
few polymer-based and lipid-based colloidal systems including polymeric nano-
particles, liposomes and emulsions have been well-studied. In this topic, the more
recent colloidal lipid systems are discussed. Lipid nanoparticles present a viable
alternative to other, more traditional, colloidal carriers. These nanoparticles not
only have the advantages of most colloidal carriers but also reduce the associated
shortcomings. Evolved from parenteral emulsions, lipid nanoparticles are com-
posed of lipid materials that are solid at room and body temperatures, such as tri-
glycerides or fatty acids. Lipid nanoparticle structures can be categorized into four
different types: solid lipid nanoparticle (SLN), nanostructured lipid carrier (NLC),
lipid drug conjugate (LDC) and polymer-lipid hybrid nanoparticle (PLN). These
lipid nanoparticles can encapsulate hydrophilic and lipophilic drugs equally well
and may potentially act as the next generation of drug carriers applied in pharma-
ceuticals. This topic focuses on the composition, structure, production, characteri-
zation and stability of lipid nanoparticles. Particular emphasis has been given to
solid lipid nanoparticles and nanostructured lipid carriers.

Keywords Colloidal carriers · Lipid nanoparticles · Solid lipid nanoparticles ·
Nanostructured lipid carriers