A series of novel branched polymeric surfactant architectures incorporating hydrophobic and hydrophilic chain ends have been synthesised by atom transfer radical polymerisation (ATRP). A range of stable emulsions have been generated to study the role and ratio of hydrophobic/hydrophilic chain ends, leading to the discovery that up to 90 mol% of chain ends can be removed while maintaining emulsion stability and comparative droplet size. As such, functionality may be added to the branched copolymer emulsifiers and the resulting emulsions. Thiolated polymers, thiomers, have long been shown to have mucoadhesive properties, forming strong disulphide linkages between the thiol-functional polymers and mucus glycoproteins. Herein, we present a novel oil-in-water emulsion stabilised by hyperbranched polymers that display tunable mucosal intreactions. Tailoring of the highly stable emulsions to either the macro or nano scale may also be achieved by varying the emulsification technique. Macroemulsions, despite being highly stable for many weeks, strong interact with mucosal surfaces, giving a burst release of oil as shown in Figure 1. Nanoemulsions, conversely, adhere fully to mucosal surfaces, with potential to deliver oil-soluble payloads. Mucoadhesion was quantitated by a flow-through model passing nanoemulsions with varying thiol content over synthetic biosimilar mucus, showing greater adhesive properties as the thiol content was steadily increased. Ex vivo multiple particle tracking of fluorescently labelled nanoemulsions further corroborated the trend while tracking the movement of individual droplets through the mucosal layer, showing control of mucous-diffusion. In vitro testing included cytotoxicity and efficacy testing of nanoemulsions loaded with drugs typical for treating corneal diseases into nanoemulsions on mucus secreting Human Conjunctival Epithelium cells (HCjE-Gi).

Tailored mucoadhesive emulsions for the delivery of therapeutic agents

256th National Meeting (2018)

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