The large-scale use of dispersants during the BP Horizon spill revealed various risks associated with these formulations, particularly the use of volatile organic compound (VOC) solvents linked to respiratory illnesses, and the poor biodegradability of surfactants. Previous attempts at solving these issues involved formulations of lecithin and polyethylene glycol ester of sorbitan monooleate (Tween® 80) that still required the use of a volatile solvent, ethanol. In this work, the Hydrophilic-Lipophilic Difference (HLD) framework was used to develop a lecithin formulation containing food-grade lipophilic (Glycerol MonoOleate – GMO- and sorbitan monooleate – Span® 80) and hydrophilic (polyglycerol caprylate) linkers in combination with a nonvolatile and mineral oil solvent with food additive status. The HLD parameters for lecithin, linkers, and oils were used to determine the lecithin-linker formulas that yielded HLD ∼0 (the surfactant phase inversion point), reaching interfacial tensions of 10−2 mN/m, and high emulsification effectiveness with diluted bitumen. This effectiveness was close to that obtained with a simulated dispersant, and superior to the lecithin-Tween® 80-ethanol formula. The lecithin-linker system produced 4–11 μm emulsified drops, sufficiently small to enhance the biodegradability of the dispersion.

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Drug delivery using liposomal carriers for targeting the afflicted areas of the host has attracted significant interest in the scientific community. While traditional liposome preparation techniques result in polydisperse suspension, postprocessing steps such as extrusion or filtering is required to obtain monodisperse liposomes in the sub-100-nm size range. Here, we describe a novel technique to synthesize monodisperse liposomes in the sub-100-nm size range using a packed bed of colloidal particles which could also be used to simultaneously encapsulate a drug. The methodology involves drying lipids dispersed in an organic solvent in a capillary packed with colloidal particles, which upon hydration with an aqueous buffer containing a drug leads to liposome formation with simultaneous encapsulation of the drug. Our experiments show that the size of the liposome is independent of the particle size or the pore size. The robustness of the process and the extremely tight control on the liposome size range make it amenable to point-of-care therapeutics involving liposomal drug delivery systems. We conclude with a discussion on the possible mechanisms for narrow size distribution of liposomes.

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