Nucleic acids, including plasmid DNA, oligonucleotides, small interfering RNA, messenger RNA and micro RNA provide significant promise in the treatment of challenging diseases. Unfortunately, their delivery as therapeutic agents has been a challenge. For example, RNAs are prone to nuclease degradation, can cause immunogenicity and are too large and negatively charged to cross the cell membrane.

Nanoparticulate delivery systems, in which cationic lipids or polymers condense nucleic acids to form “lipoplex” or “polyplex” via the negative phosphate groups of nucleic acids show high productivity and loading efficiency. The intracellular delivery of these complexes is believed to occur via endocytosis followed by endosomal escape into the cytoplasm.

Phosphorex offers a range of innovative solutions for the delivery of nucleic acid, facilitating cellular entry and endosome escape including liposomes, lipid nanoparticles and cationic polymers. Our capabilities include:

Prototype of Liposomes and LNPs

  • DNA
  • RNA
  • ASO
  • Small molecules, proteins, peptides, etc.

Formulation Optimization

  • Particle size
  • Surface charge
  • Payload loading
  • Release profile

Scale-up and Process Development and Support for

  • In vitro and in vivo feasibility studies
  • Preclinical and IND-enabling studies
  • Clinical studies via tech transfer


Liposomes are nano-sized vesicular structures consisting of an aqueous core surrounded by phospholipid layers. Cationic liposomes are biodegradable as their lipid components can be broken down by endogenous enzymes.

The advantages of liposomes for nucleic acid delivery include:

  • Interaction forces between the cationic lipid and the negatively charged nucleic acid can be modulated by varying the composition of the lipid
  • Surface modification can be made possible by including pegylated or functional lipids
  • Lipophilic, small-molecule anti-cancer drugs can be entrapped in the lipid bilayers of the liposomes and be co-delivered with the therapeutic nucleic acids

Lipid Nanoparticles (LNP)

Solid lipid nanoparticles are typically spherical and possess a solid lipid core matrix with an average diameter between 10 and 1000 nanometers and have been used for the delivery of lipophilic molecules. For the delivery of nucleic acid, an ionizable cationic lipid is used to condense a nucleic acid molecule to form the lipoplex nanoparticles.

The advantages of LNP include:

  • High loading efficiency
  • Protection of the nucleic acid from degradation
  • High permeability through the cell membrane
  • Ability to escape the endosome
  • Scale-able and reproducible processes for manufacturing

Cationic Polymers as Condensing Agents

Cationic or ionizable polymers can be used in a similar fashion to lipids to condense nucleic acids. Commonly used polymers include polyethyleneimine (PEI), polylysine, and poly(amino ester)s.

Phosphorex can screen different types of lipids and polymer condensing agents to identify the optimum solution for delivery of a specific nucleic acid.

Learn more about other Drug Delivery solutions