Steric stabilisation of self-assembled cubic lyotropic liquid crystalline nanoparticles: high throughput evaluation of triblock polyethylene oxide-polypropylene oxide-polyethylene oxide copolymers

Abstract

Nanostructured cubic lyotropic liquid crystalline colloidal particles (Cubosomes™) are of interest for applications such as drug and biomedical imaging agent encapsulation systems. Maintaining the stability and integrity of these nanoparticles over time is essential for their storage and application. It is well known that the triblock polyethylene oxide-polypropylene oxide-polyethylene oxide (PEO-PPO-PEO) copolymer, Pluronic F127, imparts a steric barrier to aggregation of non-lamellar lyotropic liquid crystalline particles. However, few other stabilisers have been reported for these systems. Using high throughput methodologies to prepare and characterise dispersions of monoolein and phytantriol, the performance of a wide range of triblock PEO-PPO-PEO copolymers (Pluronics) was evaluated for optimal stabilisation of cubosomes. It is shown that Pluronic F108 is superior to Pluronic F127 as a stabiliser of monoolein based nanostructured particles, as it preserves the integrity of the double diamond inverse bicontinuous cubic phase internal structure of the particles, whilst maintaining colloidal stability.