Molecular dynamics simulations resolve the encapsulation of testosterone propionate by both solid and liquid lipid nanoparticles

Solid lipid nanoparticles (SLNs) have a crystalline lipid core which is stabilised in solution by interfacial surfactants. They are considered favourable candidates for future drug delivery vehicles as they are capable of storing and release bioactive molecules. Following our successful study on the self-assembly of the SLN and our characterisation of the resulting structure, we have expanded our work to investigate the formation of triolein-based liquid lipid nanoparticles (LLNs) stabilised by the Brij O10 surfactant. LLNs are, like SLNs, of interest for their potential applications in drug delivery and so a thorough understanding of their structure is vital in the development and optimisation of drug delivery formulations. In this work we have characterised the structure and formation of LLNs by means of small angle neutron scattering and atomistic molecular dynamics simulations. We have also characterised and compared the processes involved in the encapsulation and localisation of a steroidal drug, testosterone propionate, for both the SLN and the LLN. By comparing the two nanostructures and the localisation of the drug within them we have shed light on the relationship between a nanoparticle’s internal structure and its role in drug delivery.