Formulation, nanoencapsulation and characterisation of mānuka oil and β-triketones for biomedical applications.

Mānuka oil (MO) is derived from mānuka shrubs in New Zealand (NZ) and presents antimicrobial properties that may help combat antibiotic resistance. However, applications of MO are limited due to volatility, sensitivity to light and heat, and the complexity of controlled administration. We used ionic gelation to encapsulate MO and its derivative β-triketones (TK) within chitosan nanocarriers. Nanoparticles were characterised for morphology, chemical composition, encapsulation efficiency and release profile. Antimicrobial properties and biocompatibility were evaluated. Nanoparticles loaded with MO or TK were successfully synthesised with an average size of 331.5 nm (PDI 0.431) and 333.5 nm (PDI 0.503), respectively. Formulations showed positive zeta potentials, stability, high yield (1.5-1.8 g), as well as oil release over 24 h. Bactericidal effect was achieved at concentrations of 3.125-25.000 mg/ml, with no cytotoxic effect. This study has demonstrated the formulation of MO and TK nanoparticles for potential applications in wound dressing, protective coating and targeted drug delivery.