**7. Conclusions**

286 Non-Viral Gene Therapy

Under low shear, the liposome surface looks thicker (Figure 10A), whereas it looks more packed with ultra-turrax treatment (Figure 10B). However, in both cases the liposome morphology is spherical. Under the highest shear, the morphology of the liposomes was not spherical, and irregularities in the surface reflect stretching of the aggregated structure (Figure 8C). These results reflect the observed change in packing and zeta potential as a

The scalable process described in Figure 11 was established based on these results and validated for the production of EPC/DOPE/DOTAP liposomes. Previous assays (data not shown) validated the changes in the purity of EPC from 99-100% (analytical grade) to 96- 98% (commercial grade) and the lipid concentration from 16 mM (used in the Bangham's

The injection of ethanol was used modified for the higher lipid concentration. Lipid concentration in the ethanol phase was previously optimized with an aim to minimize the concentration of ethanol in the liposome formulation, as well as prevent obstructions of the

Fig. 11. Schematic diagram of the scalable process for cationic liposome production.

consequence of the shear rate.

microchannels in the microfluidizer.

method) to 64 mM.

**6.1.4 Scalable top-down process for liposome production** 

The top-down and bottom-up approaches are valuable for liposome production. By understanding the physico-chemical aspects and behavior of variables involved in the process, we can establish a conscious scalable process for liposome production and connect functional liposomes, the performance of the production process, and the final properties of the gene vaccine as a product. The results presented in this chapter open opportunities for the development of new gene or non-gene vaccines in future research using scalable topdown and bottom-up processes.
