Formulation development of lyophilized, long-term stable siRNA/oligoaminoamide polyplexes

Area of Science:

• Biotechnology
• Nanomedicine
• Gene Therapy

Background:

• Non-viral small interfering RNA (siRNA) delivery using polyplexes faces challenges with liquid formulation stability.
• Lyophilization offers a promising strategy to enhance the long-term storage stability of siRNA polyplexes.

Purpose of the Study:

• To develop and evaluate lyophilized siRNA/oligoaminoamide polyplex formulations for improved long-term stability.
• To investigate the cryoprotective potential of various excipients and the influence of oligoaminoamide structure on particle stability.

Main Methods:

• Preparation of siRNA/oligoaminoamide polyplexes.
• Freeze-thaw experiments with cryoprotectants (sucrose, trehalose, lactosucrose, hydroxypropyl-β-cyclodextrin).
• Lyophilization, storage stability testing (up to 6 months at 40 °C), and reconstitution studies.

Main Results:

• siRNA polyplexes with specific oligoaminoamides maintained particle size and gene silencing efficiency after freeze-thawing, lyophilization, and reconstitution.
• Sucrose (5%/10%) and lactosucrose (7%) formulations demonstrated long-term stability at 40 °C, retaining key characteristics.
• Hydroxypropyl-β-cyclodextrin proved ineffective for stabilization, unlike other tested excipients.

Conclusions:

• Lyophilized formulations using sucrose or lactosucrose provide a viable approach for long-term stable siRNA polyplex delivery.
• The developed formulations are ready-to-use after simple reconstitution, addressing a critical limitation in non-viral gene delivery.