## 3 Results and Discussion
### Skin Accumulation of Salicylic Acid  
The amount of salicylic acid retained in the skin after 8 h of exposure was measured for each sample and is summarized in Figure 4. The control sample showed a moderate level of skin accumulation (4205.29 \(\mu\)g/g), which served as the baseline for evaluating the effect of electromagnetic fields (EMFs) on transdermal deposition. Among the tested field types, static magnetic fields with a negative polarity (SMF \(-\)15 V and \(-\)5 V) produced the highest skin accumulation values, reaching 4661.08 \(\mu\)g/g and 4595.02 \(\mu\)g/g, respectively. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Sample** & **Q\({}_{\rm 8h}\)** & **J\({}_{\rm 8s}\)** & **K\({}_{\rm P}\)\(\cdot\)10\({}^{\rm 3}\)** & **L\({}_{\rm T}\)** & **D\(\cdot\)10\({}^{\rm 4}\)** & **K\({}_{\rm m}\)** & **Q\%\({}_{\rm 8h}\)** \\  & **[ug]** & **[ug/cm\({}^{2}\cdot\)h]** & **[cm/h]** & **[h]** & **[cm\({}^{2}\)/h]** & **K\({}_{\rm m}\)** & **Q\%\({}_{\rm 8h}\)** \\ \hline Control & 335.418 \(\pm\) 38.597 & 74.29 & 7.43 & 3.78 & 1.10 & 3.37 & 3.35 \\ OMF 45 Hz & 148.440 \(\pm\) 45.398 & 44.87 & 4.49 & 4.47 & 0.93 & 2.41 & 1.48 \\ OMF 55 Hz & 172.926 \(\pm\) 53.549 & 47.00 & 4.70 & 4.40 & 0.95 & 2.48 & 1.73 \\ OMF 65 Hz & 224.520 \(\pm\) 49.953 & 80.24 & 8.02 & 5.51 & 0.76 & 5.30 & 2.25 \\ PMF 1/1 & 408.603 \(\pm\) 111.225 \({}^{\ast}\) & 100.37 & 10.04 & 4.52 & 0.92 & 5.44 & 4.09 \\ PMF 5/5 & 638.752 \(\pm\) 102.536 \({}^{\ast}\) & 132.64 & 13.26 & 2.89 & 1.44 & 4.61 & 6.39 \\ PMF 10/10 & 394.851 \(\pm\) 31.171 & 83.22 & 8.32 & 2.84 & 1.47 & 2.84 & 3.95 \\ SMF +5 V & 222.4669 \(\pm\) 23.2904 & 35.49 & 3.55 & 1.88 & 2.21 & 0.80 & 2.22 \\ SMF +15 V & 451.0258 \(\pm\) 122.687 \({}^{\ast}\) & 68.78 & 6.88 & 0.84 & 4.97 & 0.69 & 4.51 \\ SMF +25 V & 268.0432 \(\pm\) 39.0018 & 82.68 & 8.27 & 4.99 & 0.84 & 4.95 & 2.68 \\ SMF \(-\)5 V & 107.927 \(\pm\) 37.683 & 34.79 & 3.48 & 5.11 & 0.82 & 2.13 & 1.08 \\ SMF \(-\)15 V & 128.512 \(\pm\) 8.614 & 41.55 & 4.15 & 5.05 & 0.82 & 2.52 & 1.29 \\ SMF \(-\)25 V & 238.275 \(\pm\) 40.975 & 36.05 & 3.60 & 1.43 & 2.91 & 0.62 & 2.38 \\ RMF 10 Hz & 327.782 \(\pm\) 67.522 & 106.70 & 10.67 & 5.21 & 0.80 & 6.68 & 3.28 \\ RMF 30 Hz & 385.265 \(\pm\) 95.819 & 130.18 & 13.02 & 5.09 & 0.82 & 7.96 & 3.85 \\ RMF 50 Hz & 330.749 \(\pm\) 92.657 & 115.20 & 11.52 & 5.23 & 0.80 & 7.24 & 3.31 \\ \hline \end{tabular}  
* \(\rm Q_{\rm 8h}-\)cumulative amount permeated, \(J_{\rm 8s}-\)steady-state flux; K\({}_{\rm P}-\)permeability coefficient; L\({}_{\rm T}-\)lag time; D\(-\)diffusion coefficient in the skin; K\({}_{\rm m}-\)skin partition coefficient; and Q\({}_{\rm 5h}-\)percent drug permeated after 8 h; \({}^{\ast}\) L\({}_{\rm T}<0\).  
\end{table} 
Table 3: Permeation parameters of salicylic acid exposed to different magnetic fields during the 8 h permeation and a control sample without exposure to the electromagnetic field. Mean \(\pm\) SD, n = 3; \(\alpha\) = 0.05 (mean \(\pm\) SD, n = 3). \({}^{\ast}-\)statistically significantly higher penetration compared to the control. The statistically significant difference was estimated by ANOVA using Tuckey’s test. These values notably exceeded the control, indicating that SMFs of this polarity may hinder transdermal diffusion and instead promote drug retention within the skin tissue, likely due to the reduced mobility or altered diffusion kinetics of charged salicate ions. In contrast, the RMF at 50 Hz led to the lowest observed accumulation (2474.31 ug/g), suggesting that this configuration strongly favors transdermal transport over retention. Similarly, the OMF at 65 Hz (2797.66 ug/g) and SMF +25 V (2921.33 ug/g) showed a substantially reduced accumulation, which may reflect an enhanced flux through the skin and decreased local deposition. The PMF-exposed samples presented mixed outcomes. The PMF one/one and five/five resulted in moderate accumulation (3624.48 ug/g and 3740.42 ug/g), while the PMF ten/ten showed a further reduction (3317.42 ug/g).