In general mucosal surfaces can be considered as being more sensitive towards toxic effects compared to the skin, being protected by the stratumcorneum and having in general the function to protect against the environment.
Recently the pulmonary cytotoxicity of lipid nanoparticleswas investigated.Nassimi et al. compared the in vitro cytotoxicity on human alveolar epithelial cancer cell line (A549) by MTT test and neutral red assay and the ex vivo toxicity on murine precision cut lung slices.
SLN reduced the cell viability in a concentration dependent manner.
The in vitro toxic dose of SLN was approximately 2000g/ml.
While the ex vivo toxic dose was 500g/ml.
For efficient pharmaceutical drug delivery lower concentrations are expected to be needed (Nassimi et al., 2008).
Therefore, the lipid nanoparticles are a promising new drug delivery system for the lungs.
Considering the good tolerability of the lipid nanoparticles in the lung at the simultaneously higher sensitivity of the alveolar epithelial cells, especially when administering the lipid nanoparticles to the normal skin, they will be very well
tolerated and are safe for dermal application.