Introduction - Lipid Nanoparticles: Production, Characterization and Stability - page 7

depiction of a PLN system. The PLN is a suitable drug carrier for hydrophilic
drugs that are usually used clinically in their salt forms. The cationic charges on
most of these salts may lead to low drug incorporation into lipid nanoparticles. The
use of a counter-ionic polymer such as dextran sulphate to form a drug-polymer
complex has been looked upon as an interesting strategy to overcome this. The
drug-polymer complex has shown good partitioning into the lipid matrix because
of its high hydrophobicity, thereby improving drug incorporation. The PLN system
not only allows retarded release but also allows more complete release of some
drugs (Wong et al. 2004 ). These nanoparticles are more attractive because of their
capability to encapsulate and deliver multiple drugs (Wong et al. 2006a ).
Several researchers have reported increased in vitro anti-tumor activity of doxo-
rubicin-loaded PLNs compared to free doxorubicin solution. The cell lines used in
these studies showed increased drug uptake and retention (Wong et al. 2006b , c ).
The results obtained in vitro could be successfully achieved in vivo in established
animal models (Wong et al. 2007 ).
As the science of lipid nanoparticle technology has progressed, different meth-
ods of SLN production have been developed and stable SLN dispersions have been
discovered. In this topic, the efforts of researchers attempting to incorporate drugs
in lipid nanoparticles have been detailed, with the focus on SLNs, and the success
that this drug delivery system has achieved to date. Different production methods,
characterization techniques and the application of lipid nanoparticles in encapsula-
tion of drugs categorized on the basis of diseases are also discussed.
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