Background and Aim: Topical application of tretinoin (TRE) is followed by a high incidence
of side effects. One method to overcome the problem is loading TRE into lipid nanoparticles.
The potential safety of the nanoparticle materials has been always considered as a major concern. In
this in vivo study, changes in human skin biophysical parameters including hydration, TEWL,
erythema, and pH have been used to determine the safety of tretinoin loaded nano emulsion (NE) and
nanostructured lipid carriers (NLC).
Method: TRE loaded NE and NLC were prepared using a high pressure homogenizer. Skin biophysical
parameters were measured on the volar forearms of twenty healthy volunteers, before and after applying
TRE-NE and TRE-NLC lotions. All the measurements were done using respective probes of MPA
Result: We obtained particles of nanometric size (<130 nm) with narrow distribution and optimal
physical stability. None of the formulations made any statistically significant change in any of the
measured skin properties. P-values were 0.646, 0.139, 0.386, 0.169 after applying TRE-NE and 0.508,
0.051, 0.139, 0.333 after applying TRE-NLC, respectively.
Conclusion: Both formulations are reasonably safe to apply on human skin and topical application of
TRE-NE and TRE-NLC had almost similar effects on skin biophysical parameters.