## 4 Results and Discussion
As illustrated in Figure 1c, the addition of PVA could decrease the contact angle of electrospun PVP nanofiber mats from 89\({}^{\circ}\) to 71\({}^{\circ}\) for electrospun PVP/PVA nanofiber mats, implying the higher hydrophilicity and wettability of these nanofiber mats expected to be associated with the polarity and higher hydrophilic nature of PVA polymer. As a result, PVP and PVA/PVP (50/50 W/W) solutions were used in the following studies as a polymeric carrier for Bup drug because of appropriate electrospinning capacity and good solubility in water as well as producing smooth, beadles, thin nanofibers feasibly be able to performed on an industrial scale. The preparation of electrospun Bup-loaded PVP mats was carried out by the electrospinninging solutions of 15% Bup chosen based on the normal concentration of Bup in commercial dermal patches. To evaluate the impact of drug loading on the morphology of nanofibers, the electrospinninging processes carried out at fixed process parameters (same \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & **Solution** & **Viscosity** & **Shear** & **Electrical** & **Cotac Angle of** & **Average Diameter of** \\  & **Constitution** & **(Pa.s)** & **Rate** & **Conductivity of** & **Nanofibers** & **Nanofibers (nm)** \\  & & **(Pa.s)** & **(Pa.s)** & **(Pa.s)** & **(Pa.s)** & **(Pa.s)** \\ \hline
1 & Pure PVP & 121 & 19 & 226 & 89 & 49 \\
2 & PVP/PVA & 94 & 190 & 673 & 71 & 104 \\
3 & Bup(Bupnerophine)/PVP & 61 & 19 & 1628 & 88 & 55 \\
4 & Bup/PVP/PVA & 119 & 105 & 1261 & 70 & 186 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The properties of electrospinninging solutions. Figure 2: (**a**) SEM images, (**b**) fiber diameter distribution, (**c**) the contact angle of PVP/PVA nanofibers. as PVP and PVP/PVA electrospinningning) referred to the flow rate, applied voltage, needle diameter and the distance between the nozzle and collector and the geometry of the collector. The SEM analysis of electrospun Bup-loaded PVP (Bup/PVP) nanofiber mats displayed successful preparation of nanofibrous structures without adhesion (Figure 3). As seen in Figure 3, the average fiber diameter for electrospun Bup/PVP nanofiber mats was estimated to be 55 nm. The addition of Bup caused a small increase in fiber diameter than that of pure electrospun PVP mats (49 nm). To evaluate the hydrophilicity of electrospun Bup/PVP nanofiber mats, contact angles were measured (Figure 3c). The contact angle of 88\({}^{\circ}\) showed that Bup loading into PVP nanofiber mats could not have a significant effect on the wettability and hydrophilicity of pure PVP nanofiber mats (the contact angle of 89\({}^{\circ}\) for pure PVP mats, Figure 1c). Electrospun Bup/PVP/PVA nanofibers mats (containing 15% Bup, Figure 4) were prepared, and the SEM images of them are illustrated in Figure 4. The electrospinning capacity and formation of desired fiber morphology imply the potential use of electrospun PVP/PVA nanofiber mats for Bup transdermal delivery. Figure 4 shows the formation of narrow, smooth Bup/PVP/PVA nanofibers with average diameters of 186 nm. This proved that the addition of PVA led to increasing nanofibers diameter from 55 nm for Bup/PVP nanofibers to 186 for Bup/PVP/PVA nanofibers. The comparison of diameters of nanofibers (Table 2) showed that the main factor in nanofibers diameter is the existence of PVA. Figure 3: _Cont._  
Figure 4: _Cont._  
Figure 3: (**a**) SEM images, (**b**) fiber diameter distribution, (**c**) the contact angle of Bup/PVP nanofibers mat. The electrical conductivity of the solution is one of the important factors in the electrospinning capacity of a solution, yield of electrospinningning, nanofibers morphology and diameters [55]. The electrical conductivity of electrospinning solutions is listed in Table 2. PVP solution with 226 \(\upmu\)s electrical conductivity had the appropriate conductivity for electrospinning and produces the finest nanofibers.