# Positively Charged Lipid as Potential Tool to Influence the Fate of Ethosomes
## 3 Results and Discussion
### Characterization of Cationic Vesicles Made of Different Amount of DOTAP
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Formulation**} & \multicolumn{2}{c}{**Lipid Composition**} & \multirow{2}{*}{**Size (nm)**} & \multirow{2}{*}{**Polydispersity**} & \multirow{2}{*}{**Zeta Potential** (mV)} \\ \cline{2-2} \cline{5-6}  & **Lipidic Mixture** & & & & \\ \hline E & PI90G:DOTAP & 10:2 & 274 \(\pm\) 2 & 0.40 \(\pm\) 0.01 & +55 \(\pm\) 1 \\ F & PI90G:DOTAP & 10:3 & 505 \(\pm\) 22 & 0.41 \(\pm\) 0.08 & +58 \(\pm\) 3 \\ G & PI90G:DOTAP & 10:4 & 512 \(\pm\) 9 & 0.27 \(\pm\) 0.02 & +64 \(\pm\) 1 \\ H & PI90G:DOTAP & 10:5 & 616 \(\pm\) 16 & 0.32 \(\pm\) 0.06 & +69 \(\pm\) 1 \\ I & PI90G:DOTAP & 100.5 & 189 \(\pm\) 2 & 0.13 \(\pm\) 0.01 & +52 \(\pm\) 1 \\ J & PI90G:DOTAP & 100.04 & 141 \(\pm\) 1 & 0.19 \(\pm\) 0.01 & +50 \(\pm\) 0 \\ K & PI90G:DOTAP & 100.03 & 198 \(\pm\) 2 & 0.14 \(\pm\) 0.01 & +47 \(\pm\) 3 \\ L & PI90G:DOTAP & 100.2 & 216 \(\pm\) 4 & 0.25 \(\pm\) 0.02 & +47 \(\pm\) 2 \\ M & PI90G:DOTAP & 100.1 & 301 \(\pm\) 2 & 0.20 \(\pm\) 0.02 & +42 \(\pm\) 1 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Characterization studies of ethosomes containing DOTAP and phospholipid\({}^{\text{\textregistered}}\) 90 G at different molar ratios. The generic composition of formulation B was maintained, considering the final amount of 1% \(w/v\) of lipids, 40% \(w/v\) of ethanol and 59% \(w/v\) of water. Figure 2: Kinetic stability profiles of cationic endosomes using Turbiscan Lab\({}^{\text{\textregistered}}\) Expert. The results are representative of three independent analyses of samples performed at 25 \({}^{\text{\textregistered}}\)C for 1 h.  
Another stability test was performed, incubating samples at 4 \({}^{\circ}\)C for 1 month, mimicking a conservation process, and then evaluating any changes in their sizes and polydispersity index. It is interesting to note that no marked variations occurred over time in any samples (Figure 3). This was a desirable feature because, once again, the great stabilization of the nanovesicles provided by the addition of lipids with positive charge was confirmed. As can be seen in Figure 3, formulations D, E, I, J, K, and L retained sizes lower than 300 nm after 1 month of incubation. Between them, formulation D and formulation I also reported the best values of polydispersity (lower than 0.2) after 1 month of incubation. The previously described results of physicochemical characterization studies allowed us to choose the most suitable profiles. In particular, the two samples with lower mean sizes, higher positive surface charges (formulation D and formulation I) and good stability profiles over 1 month were considered for further studies. Figure 3: Characterization studies of ethosomes containing positive lipids and Phospholipon® 90 G at different molar ratios, after their storage at 4 \({}^{\circ}\)C, for up to 1 month. The dashed red lines delimit the best results recorded in terms of size and polydispersity index (below the line). Results are expressed as mean values of three different experiments \(\pm\) standard deviation.