Lyophilization of cationic lipid-protamine-DNA (LPD) complexes

Area of Science:

• Biotechnology
• Nanomedicine
• Gene Therapy

Background:

• Cationic lipid-based gene delivery systems (LPD) show potential for in vitro and in vivo cell transfection.
• Aggregation of LPD in liquid formulations limits their clinical use.
• Lyophilization is emerging as a key strategy to stabilize these systems.

Purpose of the Study:

• To investigate the lyophilization of a novel cationic lipid-based gene delivery system (LPD).
• To identify optimal lyoprotectants and freezing protocols for LPD lyophilization.
• To assess the stability of lyophilized LPD under various storage conditions.

Main Methods:

• Evaluation of various monosaccharides and disaccharides (dextrose, galactose, mannose, lactose, maltose, sucrose, trehalose) as lyoprotectants.
• Assessment of different freezing protocols, including freeze-thawing.
• Stability studies of lyophilized LPD stored at different temperatures for eight weeks.

Main Results:

• Particle size and transfection efficiency of LPD were maintained with adequate lyoprotectants.
• Disaccharides provided superior protection compared to monosaccharides.
• Fast freezing during freeze-thawing minimized LPD aggregation.
• Lyophilized LPD with 10% sucrose remained stable at room temperature for eight weeks, with no significant changes in particle size or transfection efficiency.

Conclusions:

• Lyophilization is a viable method for stabilizing LPD gene delivery systems.
• Sucrose is an effective lyoprotectant for LPD.
• Lyophilized LPD demonstrates excellent stability at room temperature, enhancing its clinical applicability.