Degradation of lyophilized lipid/DNA complexes during storage: the role of lipid and reactive oxygen species.

The presence of trace amounts of metal ions in nonviral vector formulations can significantly affect the stability of lipid/DNA complexes (lipoplexes) during acute freeze-drying. The goal of the present study was to evaluate the generation of reactive oxygen species (ROS) in dried formulations of lipoplexes and in their individual components (lipid or naked DNA). The experiments were conducted in the presence or absence of a transition metal (Fe2+).

Formulation strategies to minimize oxidative damage in lyophilized lipid/DNA complexes during storage.

It has been shown that degradation of lipid/DNA complexes (lipoplexes) continues in the dried state during storage. The goal of this study was to evaluate the ability of various strategies to minimize the formation of reactive oxygen species (ROS) in lyophilized lipoplexes during storage, including metal removal from reagents, air displacement, and fortification with chelator/antioxidant agents. Formulations containing individual chelator (DTPA) and antioxidants (L-methionine or alpha-tocopherol), or in combination, were subjected to lyophilization.

Metal contaminants promote degradation of lipid/DNA complexes during lyophilization.

Oxidation reactions represent an important degradation pathway of nucleic acid-based pharmaceuticals. To evaluate the role of metal contamination and chelating agents in the formation of reactive oxygen species (ROS) during lyophilization, ROS generation and the stability of lipid/DNA complexes were investigated. Trehalose-containing formulations were lyophilized with different levels of transition metals.

Low molecular weight dextrans stabilize nonviral vectors during lyophilization at low osmolalities: concentrating suspensions by rehydration to reduced volumes.

Stabilization of nonviral vectors during freezing and drying requires formulation with protective excipients such that transfection rates and physical characteristics are maintained upon reconstitution. While many studies have demonstrated the ability of disaccharides (e.g.

The stability of lyophilized lipid/DNA complexes during prolonged storage.

It is well known that excipients are required to protect nonviral vectors during the lyophilization process. The goal of this study is to describe the stability of lyophilized nonviral vector preparations on pharmaceutically relevant timescales and provide insight into the factors that govern long-term stability of vectors in the dried state. Lipid/DNA complexes were lyophilized in glucose, sucrose, or trehalose and stored for a period of up to 2 years at five different temperatures (-20, 4, 22, 40, 60 degrees C).