Characterization - Lipid Nanoparticles: Production, Characterization and Stability - page 65

Fig. 4.11 Proton NMR Spectra of NLC prepared with increasing amount of medium
chain triglycerides (5-50 %) compared to nanoemulsion. Reprinted from J Control Rel,
Teeranachaideekul et al. ( 2008 ), with permission from Elsevier
4.5.2 Electron Spin Resonance
Electro spin resonance (ESR), alternatively referred to as electron paramagnetic
resonance (EPR) is another technique that can be used to study the interaction of
incorporated drug molecules with the lipid nanoparticles (Ahlin et al. 2000 , 2003 ;
Kristl et al. 2003 ). ESR is a powerful, versatile and sensitive spectroscopic tech-
nique. Unlike NMR, in which the signal arises by excitation of commonly occur-
ring atomic nuclei, ESR involves excitation of unpaired, paramagnetic electrons.
This technique involves the use of paramagnetic spin probes to investigate the