Melasma is a hard-to-treat hyperpigmentation disorder. Combined incorporation of kojic dipalmitate (KDP), the esterified form of kojic acid, and rosehip oil, an oil with antioxidant and skin-regenerating properties, into nanocarrier systems appears to be a suitable strategy to develop high-performance formulations. A high-energy method (Ultra-Turrax^®) was used to develop nanoemulsions containing up to 2 mg/mL KDP, 5% rosehip oil, and 7.5% surfactant. Formulations were characterized regarding droplet size, size distribution, pH, density, morphology, KDP content, incorporation efficiency, and stability under different temperature conditions. A scale-up study was conducted. Skin permeation, antioxidant potential, and tyrosinase inhibitory activity were assessed in vitro. Cell viability studies were also performed. Results showed that nanoemulsions containing 1 and 2 mg/mL KDP had incorporation efficiencies greater than 95%, droplet size smaller than 130 nm, suitable size distribution, zeta potential of approximately −10 mV, and good stability over 30 days of refrigerated storage. The nanoemulsion containing 1 mg/mL KDP was chosen for further evaluation because it had lower nanocrystal formation, greater scale-up feasibility and allowed KDP permeation up to the epidermis similarly than observed for 2 mg/mL KDP. This formulation (1 mg/mL KDP) showed antioxidant and depigmenting efficacy, close to that of 1 mM ascorbic acid. No cytotoxicity was observed in formulations concentrations ranging from 0.06% to 1%.

Polymeric nanocapsules associated with kojic acid dipalmitate (KDP) and rosehip oil can be a strategy to obtain high-performance skin whitening/lightning formulations. Nanocapsules containing 0.1% of KDP and 5% of rosehip oil were developed with different polymers (Eudragit RS100, Eudragit S100, poly­(ε-caprolactone) (PCL) and poly­(d,l-lactide-co-glycolide) (PLGA)) to limit the contact of KDP with the external media and avoid its degradation. The nanocapsules had a diameter of less than 200 nm, with suitable size distribution, a pH range between 2.5 and 5.0, a KDP content of 0.9 mg/mL and an encapsulation efficiency above 99%. The zeta potential was positive for the Eudragit RS100 nanocapsules and negative for the other nanocapsules. The PLGA nanocapsules were selected due to better stability results, since there was no decay in KDP content after 180 days (refrigerated storage). The in vitro skin permeation assay showed that KDP reaches the epidermis. This formulation showed in vitro antioxidant activity through both the DPPH assay and the β-carotene/linoleic acid assay when used at 25 μg/mL of KDP, with higher activity than a kojic acid solution (KDP correspondent concentration) and, at 13.75 μg/mL, inhibited tyrosinase in vitro to 17%, significantly greater than the kojic acid solution. A 25% melanin reduction was obtained after normal human epidermal melanocytes (NHEM) were treated with 3.1 μg/mL of KDP. Cytocompatibility was observed after 24 h treatment with up to 6.25 μg/mL of the formulation in fibroblast-like cells (3T3-L1) and up to 3.1 μg/mL in NHEM. Therefore, PLGA nanocapsules containing KDP and rosehip oil have potential for use in skin whitening/lightning formulations.

Plants are a source of a variety of compounds, such as vegetable oils, which are rich in fatty acids and possess skin-whitening properties. Considering the hyperpigmentation treatment challenges (lack of efficacy or aggressiveness), the constant search for new whitening substances is necessary. Given vegetable oils’ potential and application in dermatological and cosmetic products, we reviewed the scientific literature on vegetable oils with skin depigmenting activity. It was observed that a variety of species (Adansonia digitata, Arctium lappa, Argania spinosa, Astrocaryum vulgare, Bertholletia excelsa, Borago officinalis, Camellia oleifera, Cucurbita moschata, Euterpe oleraceae, Hevea brasiliensis, Moringa oleifera, Nicotiana tabacum, Oenocarpus bataua, Oenothera biennis, Panax ginseng, Passiflora edulis, Pentaclethra macroloba, Perilla frutescens, Sapindus mukorossi, Taiwanese species Taichung selective No. 4 (TCS4) (Adlay bran), Torreya grandis) were evaluated in vitro regarding their skin whitening properties. All the studies demonstrated that the oils have skin whitening properties and that the oils’ activity is related to their composition. The harvesting period, as well as the extraction method, impact on the oils’ properties, hence in their activity. The use of vegetable oils can have advantages over an isolated compound as their components can have synergistic or adding effects. When conducting skin whitening experiments, it is recommended to employ multiple assays because vegetable oils can influence skin whitening through various mechanisms. Furthermore, more clinical trials should be encouraged, considering the potential of vegetable oils as skin-lightening ingredients. More innovative and effective formulations can be obtained using vegetable oils for skin whitening purposes.

The cosmetics are commonly placed in plastic packaging that have the important function of protecting the product. However, the cosmetics packaging can contribute to the total microbial load of the product, leading to product deterioration and putting the health of users at risk. The main purpose of this research was the microbiological evaluation of cosmetics packaging obtained from cosmetics production establishments (an industry and four compound pharmacies) from Vale do Taquari, Rio Grande do Sul, Brazil. Based on the results of a questionnaire applied at the moment of packaging acquisition, previous sanitization is performed for compound pharmacies packaging, with different handling of the packaging, whereas in the industry the process of packaging sanitization does not occur. However, this sanitization was not considered enough to guarantee the absence of microorganisms in the packaging, since a microbial growth was observed for 6 out of the 16 evaluated containers obtained from compound pharmacies, and for 2 out of the 4 industrial containers. Although several containers were contaminated, a few number of CFU/mL (from 1- 4) was isolated from each sample. Staphylococcus bacteria were the most common type of contamination, with S. aureus being identified in one sample. Not performing prior sanitization or storing packaging with the lid open led seems to lead to a higher microbial contamination of the packaging. Hence, both the sanitization process and the storage of packaging play an important role in guaranteeing packaging and cosmetics quality. The present investigation points for the importance of microbiological quality control of cosmetics packaging.

Drug nanocrystals, composed solely of active substance and stabilizer, have recently been proposed for cutaneous applications, including the management of skin fungal infections (dermatomycoses), which are often difficult to treat. Clioquinol nanocrystals were obtained using different preparation methods, drug concentrations, surfactants, and bead sizes. The selected nanocrystal suspension (bead milling, 1% drug, 1% polysorbate 80) exhibited an average particle size of approximately 300 nm (polydispersity index of 0.254), a zeta potential of −7.6 mV, a pH value of 5.4, a drug content of about 97% (relative to 10 mg/mL), and a nanocrystallization efficiency of approximately 96%. The presence of the surfactant was essential to ensure nanocrystal stability for 90 days at room temperature. Overall, the results indicate that clioquinol nanocrystals are possible to be obtained by small-scale wet bead milling and present suitable nanometric features, being considered a promising alternative as cutaneous antifungal therapy.