Lignin-based Pickering stabilisers for innovative cosmeceutical formulations

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Saponin-based natural nanoemulsions as alpha-tocopherol delivery systems for dermal applications

Publication . Schreiner, Tatiana B.; Santamaria-Echart, Arantzazu; Colucci, Giovana; Plasencia, Paula; Costa, Patrícia Santos; Dias, Madalena M.; Pinho, Simão; Barreiro, M.F.

Nanoemulsions can be produced using simple methods and compounds from natural sources. They can increase water dispersibility and bioavailability and optimise active ingredient dispersion in particular skin layers. Lipophilic compounds of the vitamin E family (tocopherols and tocotrienols) are well-known for their high antioxidant activity and capacity to protect the skin from oxidative stress. In this context, oil-in-water (o/w) nanoemulsions with and without α-tocopherol (Vitamin E, VE) were formulated with two emulsifier alternatives, Quillaja saponin (QS), and a combination of QS with Tribulus terrestris (QSTT) (50/50, w/w). The emulsions were evaluated concerning stability, microstructure, droplet size, colour attributes, encapsulation efficiency, UV photostability, antioxidant activity, and in vitro permeation studies to assess the delivery potential. Results showed highly stable systems, with round-shape droplets of 80–121 nm size. QS and QSTT samples’ colours were close to white and light brownish, respectively. The topical nano cream had the capacity to entrap VE, producing a protective effect from UV degradation, and very significant antioxidant activity, with IC50 values around 0.01 %wt. The skin permeation profiles showed the efficiency of the formulations in the delivery of VE, with permeabilities between 64 and 74 μg/cm2, while the control sample showed no VE permeation.

2023Journal article

Open access

Optimisation of stability and colouring power of double emulsion systems loaded with Daucus carota L.

Publication . Teixeira, Liandra Gracher; Silva, Samara Cristina; Colucci, Giovana; Santamaria-Echart, Arantzazu; Peres, António M.; Dias, Madalena M.; Barreiro, Filomena

Anthocyanins (ACNs) are water-soluble bioactive flavonoids found in flowers, roots, leaves, seeds, and stalks. ACNs cover a wide palette of colours, from blue and purple through orange to red1,2. They are used in the food industry (food colourant with E163 code), namely in fruit juice concentrates, nectars, jellies, yoghurts, marmalades, potato chips, ice creams, and soft drinks, replacing the synthetic Red 40 colourants. They also have diversified pharmaceutical and cosmetic uses due to their colouring and antioxidant attributes. However, their instability due to pH, light, and temperature is a major concern. This study used a double water-in-oil-in-water (W1/O/W2) emulsion technique to prevent rapid colour loss and colour variability with pH of a commercial black carrot extract (Fig. 1). A Central Composite Rotatable Design (CCRD) 22 was used to examine the effects of colourant concentration (wt%) and emulsion ratio ((W1/O)/W2) on stability parameters (droplet size (D4,3), creaming index (CI), and colourimetric values (L*, a*). The main objective was to find an optimised formulation in terms of colourant potential and emulsion stability. Measurements were taken at 1, 7, 15, and 30 days. The optimal experimental design revealed two optimal solutions: 1) 48/52 (W1/O)/W2 ratio with 6 wt.% colorant, and 2) 41/59 (W1/O)/W2 ratio with 11 wt.% colourant. These formulations showed lower creaming index and droplet sizes with higher colourant potential. After accounting for the effect of time, the optimal condition was 6 wt% colourant concentration and 48/52 v/v (W1/O)/W2 emulsion ratio. A stable colour was maintained after 30 days (L*: 44.11±0.03, a*: 25.79±0.01, D4;3: 9.62 ± 0.1 µm, and CI: 14.55±0.99%). These findings are promising and might be applicable to produce novel colourants to be applied in several industries, such as food and cosmetics.

2024Conference object

Open access