Bioactive Molecules Niosomes Containing a Span 80 and Tween 20 Surfactant Mixture: Obtaining, Physico-Chemical Characterisation and Stability

Background: Niosomes are spherical, non-ionic surfactant-based vesicular carriers structured as lipid bilayers that are widely utilised in pharmaceutical and cosmetic research for integration into topical formulations like gels and creams. Objective: This study presents a novel contribution concerning the preparation of niosomes using a mixture of distinct Span and Tween non-ionic surfactants and diverse biomolecules. Methods: In this context, novel formulations of niosomes have been prepared by including into their composition a mixture of Span 80 and Tween 20 (in order that HLB = 8.42) non-ionic surfactants with cholesterol (Chol) in a Span 80:Tween 20:Chol = 2:1:1 molar ratio, which is meant to optimise their rigidity and stability, respectively. Their preparation was achieved through three methods: probe sonication, bath sonication and thin-film hydration (TFH). Additionally, the samples were analysed by means of Fourier-Transform Infrared Spectrometry (FT-IR). On the other hand, the antioxidant capacity profile of the formulas of interest was assessed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical reduction method. The investigated bioactive molecules were ascorbic acid (AA) and a yellow dye of fungal origin, previously extracted from an Epicoccum nigrum strain. Results: The average particle size of the niosomes ranged from 2.771 ± 0.808 to 3.397 ± 0.917 μm. Furthermore, high entrapment efficiency was observed for both AA (92.71 ± 0.01%) and the fungal dye (83.54 ± 0.08%), particularly in the formulations prepared through an optimised procedure. The gathered results illustrated that the highest DPPH radical scavenging percentage (48.71 ± 0.05%) occurred when the bath sonication technique was applied. Conclusions: These findings demonstrate that the entrapment of active biomolecules depends on the preparation methods utilised. Furthermore, employing fungal dyes represents a promising strategy to simultaneously enhance both the antioxidant and dyeing capacities exhibited by the formulated niosomal colloidal systems.