Understanding microscopic properties and drug diffusion kinetics in a long-acting peptide hydrogel drug delivery implant for combined contraception and HIV prevention.

There is a major need for a single effective platform to delivery both HIV/AIDS and contraceptive drugs over a prolonged period e.g. 28 days We are developing a hydrogel implant, composed of biologically stable peptide-like molecules termed peptoid-D-peptides, that form gels in response to enzymes present within the skin. Patients struggle to adhere to complex regimens of these medicines, which require a cocktail of drugs to be taken several times daily. Our therapy removes this need, improving adherence to medication and reducing mother to foetal HIV transmission. This project will explore the role of gel fibre structure and entangled gel fibre networks on both i) mechanical (gel formation, rheology, gel strength) and ii) drug release properties (drug cleavage from peptoid-D-peptide, drug diffusion). Small angle neutron scattering will be used to probe the properties of gel fibres in the presence of multiple HIV/AIDS and contraceptive drugs. This will provide SANS data that will be valuable in optimising the peptoid-D-peptide’s chemical structure and formulation parameters for 28 day combined delivery of HIV/AIDs and contraceptive drugs within one injectable product.