Amphiphilic lipids and phospholipids can self-assemble in aqueous environments to form nanoscale structures. Their composition, organisation and interfaces can determine where a payload resides, how it is protected and how the formulation behaves during development.
Hydrophilic head groups and hydrophobic regions give amphiphilic lipids their ability to organise in water. Molecular geometry, composition, payload and process conditions can influence the resulting nanostructure.
These terms describe related but distinct systems. Selecting a platform requires consideration of payload properties, intended biological interaction, product profile and manufacturing route.
Liposomes are vesicular systems typically composed of one or more lipid bilayers surrounding an aqueous compartment. Hydrophilic molecules may associate with the aqueous compartment, lipophilic molecules may partition into the bilayer, and amphiphilic molecules may localise at interfacial regions.
Performance can depend on lipid composition, membrane packing, payload localisation, surface properties and the surrounding biological environment.
LNPs are nanoscale lipid assemblies designed to formulate challenging payloads. Unlike a classical bilayer-enclosed liposome, an LNP may have a more complex internal organisation determined by its composition, payload and manufacturing process.
Relevant payload classes may include nucleic acids, oligonucleotides, peptides, proteins and selected poorly soluble molecules.
Phospholipids can form bilayers, vesicles and other organised structures. Molecular geometry, membrane packing and lipid composition may affect fluidity, permeability, leakage, stability and interaction with biological membranes.
The appropriate structure is selected and evaluated against the intended formulation function.
A target particle size alone does not define a successful formulation. Size distribution, morphology, surface properties, stability and payload behaviour can be interdependent.
Mean size and polydispersity index provide complementary information about the particle population and can inform colloidal stability, consistency and process control.
Surface charge, interfacial composition and particle morphology can influence dispersion stability, biological interaction and transport behaviour.
Loading or encapsulation must be considered alongside payload integrity, localisation, retention and release under relevant conditions.
Formulation optimisation needs to anticipate manufacturability. Candidate systems can be assessed for composition control, particle attributes, payload-related quality, stability, reproducibility and sensitivity to process conditions.
Relevant attributes may include size, PDI, surface charge, morphology, payload content, free versus associated payload, integrity, release and stability.
Process sequence, mixing, concentration, handling and material compatibility can influence product attributes and should be considered early.
Scale-up is not assumed from a small-volume result. Reproducibility and process robustness require deliberate evaluation across development stages.
Share the payload class, intended route, target product profile and current development stage. We can frame a focused feasibility or optimisation programme without requiring disclosure of confidential formulation details at the outset.
