The crossflow injection technique: an improvement of the ethanol injection method

A novel scalable liposome preparation technique for pharmaceutical application is presented. Previous experiments have shown that the concept of continuous crossflow injection is a promising approach. For the characterization of the process, we focus on the influencing parameters like the lipid concentration, the injection hole diameter, the injection pressure, the buffer flow rate, and system performance. These experiments demonstrate that the injection hole diameter and the system performance do not influence the vesicle forming process and that a minimum of buffer flow rate is required to affect batch homogeneity. In contrast, strongly influencing parameters are lipid concentration in combination with increasing injection pressures. After exceeding the upper pressure limit of the linear range, where injection velocities remain constant, the vesicle batches are narrowly distributed, also when injecting higher lipid concentrations. Reproducibility and scalability data show similar results with respect to vesicle size and size distribution and demonstrate the stability and robustness of the novel continuous liposome preparation technique.