## 4 Lipsosomal Microencapsulation Using Conventional and Innovative Methods
### Conventional Methods  
#### 4.1.1 Thin Film Hydration  
The Thin Film Hydration (TFH) method, also known as the Bangham method, entails the solubilisation of lipid material in a volatile organic solvent, such as hexane, methanol, or chloroform. The solvent is then evaporated to form a thin lipid film, typically using rotary vacuum evaporation or nitrogen blowing. This lipid film is subsequently hydrated to induce liposome formation (Figure 3) [55]. Additional steps, such as extrusion or sonication, are often employed to control the diameter and size distribution of the liposomes [56]. The Bangham method typically produces liposomes with heterogeneous MLVs that exhibit low encapsulation efficiency. However, the duration of hydration and the conditions of agitation are critical in determining the amount of liquid encapsulated within the MLVs. For instance, studies have demonstrated that hydrating the lipid for 20 h with gentle shaking results in greater retention of the aqueous phase in comparison to hydrating for two hours with vigorous shaking, despite the size distribution of the MLVs remaining unchanged [57]. This evidence suggests that a slower hydration process is associated with a higher aqueous volume entrapment.  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{1}{c}{**Methods**} & \multicolumn{1}{c}{**Organic Solvent**} & \multicolumn{1}{c}{**Process Time**} & \multicolumn{1}{c}{**Process Type**} & \multicolumn{1}{c}{**Liposome Size**} \\ \hline \multirow{6}{*}{Conventional} & TFH & Yes & \textgreater{}1 & Batch & Variable \\  & [47] & & & & \\  & REV & & & & \\  & [48] & Yes & 2–3 h & Batch & Variable \\  & Membrane & & & & \\  & Extrusion & Yes & 1–2 h & Batch & dependent on pore \\  & [49] & & & & \\ \hline \multirow{6}{*}{Innovative} & Microfluidics & & & & \\  & Dense Gas & Yes & 15–30 min & semi-continuous & 50–100 \(\mu\)m \\  & [50] & & & & \\  & Ethanol Injection & & & & \\  & [51] & Yes & 15–30 min & semi-continuous & 200–250 nm \\  & SCRPE & Minimal & 2–3 h & Batch & 200 nm \\  & DESAM & & & & \\  & [53] & Yes & 45–60 min & continuous & 100–400 nm \\  & SAS & & & & \\  & [54] & Minimal & 2–3 h & Batch & \textless{}50 \(\mu\)m \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of conventional and innovative methods of liposomal microencapsulation.  
The study by [PERSON] et al. [58] explored the formulation of silymarin-loaded liposomes aimed at enhancing hepatic targeting, with a particular focus on the influence of formulation parameters on encapsulation efficiency and liver-specific delivery. The research assessed the impact of multiple factors, including lipid composition (specifically phosphatidylcholine and cholesterol), the concentration of cholesterol (ranging from 30% to 50% molar ratio), the ratio of drug to lipid (varying from 1:5 to 1:15), and the incorporation of \(\beta\)-sitosterol \(\beta\)-D-glucose (Sito-G) as a hepatic targeting ligand in concentrations ranging from 0.17 M to 0.33 M.  
Encapsulation efficiency was observed to decrease as the concentration of Sito-G increased, with values dropping from approximately 70% to around 60%. The study also examined the drug release profile, noting that the presence of Sito-G modified the release in non-PEGylated liposomes, whereas in PEGylated liposomes, the release profile remained largely unaffected by Sito-G. The mean particle size of the silymarin-loaded liposomes was optimized to enhance cellular uptake and drug delivery efficacy, typically falling within a range suitable for efficient hepatic targeting. In vitro experiments using HepG2 cells highlighted the differences in drug uptake efficiency between non-PEGylated and PEGylated liposomes. Non-PEGylated liposomes containing 0.17 M Sito-G exhibited the highest cellular drug uptake at 37.5%, while PEGylated liposomes showed a maximum uptake of 18% at both 0.17 and 0.33 M Sito-G ratios. The liposomes, with a controlled size of 100-150 nm after extrusion, demonstrated enhanced targeting efficiency and consistent in vitro performance [58].