## 3 Results and Discussion
### Dissolution Test  
Figure 1 shows the dissolution profiles of GEF from GEF pure and solid dispersions of GEF (F1, F2 and F3) at pH 1.2 (0.1 N HCI). The 0.1 N HCI solution was used as release medium because it simulates the gastric environmental pH conditions. GEF pure was used as a reference product in this study. The low pH release medium was used for dissolution tests because, being a weak base with two pKa values (pKa\({}_{1}\) 5.4 and pKa\({}_{2}\) 7.2), GEF ionizes completely with high aqueous solubility [25]. The GEF pure depicted poor release due to its poor aqueous solubility. The GEF pure showed only 37.26 \(\pm\) 2.89% of cumulative drug release till 2 h. The study suggested a quick release of GEF from the GEF SDs prepared with TPGS and SLS. The maximum GEF release was achieved within 60 min from the SDs. The presence of surfactants (TPGS in F1) and SLS (in F2) was able to reduce the interfacial tension between the drug and release medium, leading to enhanced GEF solubility. Among TPGS and SLS, the SDs prepared with TPGS (F1) showed faster release than the SDs prepared with SLS (F2). Within 5 min, a significant difference in the GEF release was observed between F1 and F2. Around 19.92 \(\pm\) 1.01% drug was released from F1 (GEF-TPGS SDs), whereas only 13.38 \(\pm\) 1.16% drug release was found from F2 (GEF-SLS SDs) within 5 min. As the time increases, a gradual increase \begin{table}
\begin{tabular}{c c c c c c c} \hline  & & \multicolumn{4}{c}{**Saturation Solubility (Mean \(\pm\) SD, \(\mu\) = 3)**} \\ \cline{2-7}  & \multicolumn{2}{c}{**In 1.2 N HCl**} & \multicolumn{2}{c}{**Phosphate Buffer**} & \multicolumn{2}{c}{**Phosphate Buffer**} \\
**GEF SDs/GEF Pure** & **(pH 1.2)** & \multicolumn{2}{c}{**(pH 5.6)**} & \multicolumn{2}{c}{**(pH 7.2)**} \\ \cline{2-7}  & **Solubility (\(\mu\)g/mL)** & **Log Value** & \multicolumn{2}{c}{**Solubility**} & \multirow{2}{*}{**Log Value**} & **Solubility** & \multirow{2}{*}{**Log Value**} \\  & & & & & & (\(\mu\)g/mL) & \\ \hline F1 & 1003.69 \(\pm\) 138.15 & 3.01 & 386.24 \(\pm\) 53.58 & 2.58 & 99.78 \(\pm\) 13.88 & 1.99 \\ F2 & 707.81 \(\pm\) 92.13 & 2.85 & 295.82 \(\pm\) 32.06 & 2.47 & 71.48 \(\pm\) 8.94 & 1.85 \\ F3 & 1271.21 \(\pm\) 144.47 & 3.10 & 532.32 \(\pm\) 84.42 & 2.72 & 129.36 \(\pm\) 15.73 & 2.11 \\ GEF Pure & 303.85 \(\pm\) 59.39 & 2.48 & 181.86 \(\pm\) 13.99 & 2.26 & 31.24 \(\pm\) 6.75 & 1.49 \\ \hline \end{tabular}
\end{table} 
Table 2: Solubility of GEF SDs and GEF pure in different solvents. The values represent the mean and standard deviation of three measurements. in GEF release was achieved from both the SDs (F1 and F2). The F1 showed a maximum release of GEF (94.76 \(\pm\) 3.45%), while F2 released around 85.71 \(\pm\) 4.38% at 120 min. The dissolution of GEF-TPGS SDs (F1) was further controlled by the addition of HP \(\beta\)-CD as a carrier. For this, the F1 was further incorporated into the HP \(\beta\)-CD as F3 to modify the GEF release pattern. After incorporation of HP \(\beta\)-CD, the release pattern of GEF was significantly improved. The formation of the inclusion complex further enhanced the release behavior of GEF. Around 90.32 \(\pm\) 3.09% and 99.18 \(\pm\) 3.61% of the drug was released from F3 within 60 min and 120 min, respectively. Overall, the dissolution profiles showed that TPGS has a higher dissolution rate in comparison to the intrinsic dissolution of GEF in 0.1N HCl as compared to the SLS as the GEF-SLS SDs (F2) had the lowest effect on the dissolution of GEF. This might be due to the degradation of SLS in the strong acidic environment of 0.1N HCl. The utilization of TPGS would further facilitate the intestinal permeability of GEF as TPGS also serves as a penetration enhancer in association with its p-glycoprotein' efflux inhibition activity. Thus, improved aqueous solubility and intestinal penetration would lead to enhanced oral bioavailability of the poorly soluble anticancer agent [42]. The in vitro release data were further evaluated by computing the dissolution efficiency (%DE) and mean dissolution time (MDT).