## 3 Results  
### creams and Gels Screening  
We selected a commercial group of multiphase creams (W/O and O/W) and gels to study their flow properties and characteristics after adding 10% HPE (both hydrophilic and lipophilic extracts), 1% NAG, or 1% nNAG. More specifically, we considered two hydrophilic O/W creams (eudermic (C1) and neutra (C2)), one lipophilic W/O cream (C3), one lipophilic gel (G1), one polymeric PLO gel (G2), and one hydrophilic gel (G3). In each cream or gel, 1% NAG or 1% nNAG was incorporated, whereas 10% HPE (hydrophilic or lipophilic) was added to the hydrophilic or lipophilic vehicles on the basis of their chemical properties. Additionally, one mixture was prepared by simultaneously adding 10% HPE and 1% nNAG. These formulations were studied to evaluate the suitability of creams or gels for a future topical application on inflamed and aching joints and skin.  
The results show that all formulations containing hydrophilic HPE had a dark brown color, whereas lipophilic HPE resulted in a yellow color, both of which are not favored by final consumers. The inclusion of 1% nNAG did not alter (C1) or reduce (C2 and C3) the viscosity of the creams, whereas 1% NAG increased it for all three, and 10% HPE increased it in C1 and C3 and reduced it in C2. The simultaneous inclusion of 10% HPE and 1% nNAG (Mix) in the creams did not alter (C1) or decrease the viscosity (C2 and C3) (Table 1 and Figure S1). nNAG (1%) in the lipophilic (G1) and PLO (G2) gels contributed to a decrease in the viscosity, whereas it did not alter it in the hydrophilic (G3) gel. Regarding 1% NAG, it increased the viscosity in G1 and G3 and reduced it in G2. The inclusion of 10% HPE in the lipophilic (G1), PLO (G2), and hydrophilic (G3) gels led to a great decrease in the viscosity, whereas the inclusion of 10% HPE plus 1% nNAG (Mix) reduced it in G1, markedly reduced it in G2, and slightly increased it in G3 (Table 1 and Figure S1). These findings suggest that 10% HPE destroys the texture of these emulsions.  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Name**} & **Emulsion** & \multirow{2}{*}{**NAG**} & \multirow{2}{*}{**nNAG**} & **HPE** & **HPE** & **Mix of** & **Mean** & **Mean** \\  & & & & & **Lipo-** & **NS** & **NS** & **Viscosity** \\  & & & & & & **vs. SR** & **vs. SR** \\ \hline \multicolumn{8}{c}{Eudermic} \\ \hline C1 & O/W & & & & & & 114.3 \(\pm\) 1.2 & 9850.1 \(\pm\) 98 \\ \hline C1 & O/W & X & & & & 104.76 \(\pm\) 2 & 12,555.8 \(\pm\) 25 \\ \hline C1 & O/W & & X & & & 103.2 \(\pm\)1 & 10,329.6 \(\pm\) 10 \\ \hline C1 & O/W & & & X & & 115.3 \(\pm\) 1.2 & 12,393.8 \(\pm\) 12 \\ \hline C1 & O/W & & & X & 100.9 \(\pm\) 1 & 9702.5 \(\pm\) 9.7 \\ \hline \multicolumn{8}{c}{Neutral} \\ \hline C2 & O/W & & & & & 79.7\(\pm\) 1 & 6324.3 \(\pm\) 6.3 \\ \hline C2 & O/W & X & & & 108.44 \(\pm\) 2.2 & 9442.6 \(\pm\) 18.8 \\ \hline C2 & O/W & & X & & 49.9 \(\pm\) 5 & 4475.6 \(\pm\) 8.8 \\ \hline C2 & O/W & & X & & 41.4 \(\pm\) 5 & 4064.6 \(\pm\) 8 \\ \hline C2 & O/W & & & X & 60.3 \(\pm\) 1 & 5482.1 \(\pm\) 10.8 \\ \hline \hline \end{tabular}
\end{table}
Table 1: cream and gel screening.  
At the end of the screening procedure, we selected a short list of creams and gels, including the eudermic cream (C1), lipophilic cream (C3), hydrophilic gel (G3), and lipophilic gel (G1), and compared the effects of 1% nNAG and 1% NAG on the flow properties of the considered multiphase formulations, excluding 10% HPE from these analyses. We decided to exclude PLO (G2) because the inclusion of 10% HPE or 1% nNAG/10% HPE (Mix) exhibited very different flow properties compared to 1% NAG or 1% nNAG. Moreover, we excluded neutra C2 because it is hydrophilic, as is eudermic C1, which we preferred.