Introduction - Lipid Nanoparticles: Production, Characterization and Stability - page 5

Fig. 1.1 Types of lipid nanoparticles. a Solid lipid nanoparticle, b Nanostructured lipid carrier,
c Lipid drug conjugate, d Polymer-lipid hybrid nanoparticle
Table 1.2 Potential advantages of solid lipid nanoparticles
Biocompatible and biodegradable colloidal carrier
Prevention of degradation of drug in body fluids due to encapsulation
Increased drug payload
Longer half-life of drug
Possibility of sustained-release and controlled-release of drugs
Longer shelf life
Increased drug dissolution and absorption, improved bioavailability
Drug targeting
Large scale manufacturing
Feasibility of sterilization
them (Jain et al. 2010 ). Several potential advantages associated with SLNs are
listed in Table 1.2 (Das and Chaudhury 2011 ; Fang et al. 2008 ; Noack et al. 2012 ;
Saupe et al. 2006 ).
SLNs have been widely studied for delivery of drugs through dermal (Schäfer-
Korting et al. 2007 ; Souto et al. 2007 ), peroral (Jenning and Gohla 2001 ), par-
enteral (Yang et al. 1999 ), ocular (Attama et al. 2008 ; Cavalli et al. 2002 ; Gasco
et al. 2003 ), pulmonary (Chattopadhyay et al. 2007 ; Liu et al. 2008 ; Videira et al.
2002 ) and rectal (Sznitowska et al. 2001 ; Sznitowska et al. 2000 ) routes.
1.4.2 Nanostructured Lipid Carrier (NLC)
Evolved from the SLNs, NLCs were created with a controlled nanostructure of the
lipid. NLCs are composed of a binary mixture of a solid lipid and a spatially distinct
liquid lipid. As a result, they do not form a perfect crystal. The imperfections pre-
sent in the solid matrix accommodate the drugs either as molecules or as amorphous
crystals (Saupe et al. 2005 ). A schematic depiction of an NLC is shown in Fig. 1.1 b.
NLCs have been utilized, for example, in dermal applications (Müller et al. 2007 ).
The major advantage of NLCs over SLNs is that many drugs are more soluble in
a liquid lipid than in a solid lipid. In both cases, the drug is solubilized in the lipid