Nanoemulsions (NEs), emulsified systems with diameter between 20 and 500 nm, are promising in cosmetic science due to stability and efficient transportation of lipophilic substances, such as volatile oils, favoring the skin penetration to carry out the biological activity. Volatile oil of Matricaria recutita L. (VOMR) has several therapeutic effects, but the lability of the volatile oils requires appropriate vehiculation in NEs. Besides, the hydrophilic-lipophilic balance (HLB) parameter for VOMR is not described in the literature. Therefore, NEs composed of Span^® 80, Tween^® 80, PEG-7 glyceryl cocoate, glycerin and water were developed by the high-energy method. The NEs were characterized by organoleptic, physicochemical and morphological evaluations as well as the stability evaluation was conducted at different temperatures for 60 days. The NEs obtained with and without VOMR exhibited translucent aspect, pH of 4.82 and 5.62; average diameter of 104.97 ± 4.03 and 92.32 ± 6.17 nm; polydispersity index of 0.27 ± 0.06 and 0.31 ± 0.04, and zeta potential of -28.37 ± 3.06 and -36.48 ± 6.56 mV, respectively. The encapsulation of VOMR was around 83% into the NE and confirmed by visualization through scanning electron microscopy - field emission gun. The stability study demonstrated that refrigeration is the optimal storage condition because the conservation of the NEs characteristics. As a result, the present study describes for the first time HLB value near 7 for VOMR. Thus, NE with this volatile oil was developed with suitable characteristics, contributing to technology development of phytopharmaceuticals for topical application to the skin.

This study reports the experimental design-based optimization of ionic self-assembled lecithin (LC)–chitosan (CS) hybrid nanoparticles using progesterone (PG), a poorly water-soluble lipophilic model drug, to investigate the design-driven development of these nanoparticles. Nanoparticles were prepared by ethanol injection and optimized using a 3² factorial design to establish structure–property relationships between formulation variables and nanoparticle physicochemical performance. The optimized formulation exhibited a nanometric diameter (~ 230 nm), a narrow size distribution, a positive surface charge ( ~ + 20 mV), and a high encapsulation efficiency (~ 97%). Structural analyses (XRD and FTIR) suggested reduced PG crystallinity and interactions among the formulation components, supporting PG incorporation into the hybrid nanoparticles, while field-emission scanning electron microscopy (FESEM) revealed a uniform spherical morphology. Surface charge played a key role in mucin interactions by promoting electrostatic interactions, as evidenced by increased particle size, surface charge reversal, and a binding efficiency of approximately 28%. The hybrid nanoparticles exhibited pH-responsive drug release, with greater release under acidic conditions (73.9% at pH 4.0) than at neutral pH conditions (48.6% at pH 7.4) over 12 h. Release kinetics were compatible with diffusion-controlled behavior (n < 0.45), indicating transport through the ionically stabilized hybrid lipid–polymer matrix. This study provides a design-driven system for understanding how LC and CS composition modulates the colloidal organization, drug incorporation, surface charge, mucin interaction, and pH-dependent release of PG-loaded hybrid nanoparticles. These findings contribute to PG nanoparticle vaginal mucosal drug delivery by supporting the rational design of lipid–polymer nanocarriers for poorly water-soluble steroidal drugs and by identifying formulation attributes that may guide future mucosal-oriented delivery studies. Graphical abstract

Eucalyptus benthamii essential oil is rich in α-pinene and offers antioxidant and anti-inflammatory benefits. This study focused on synthesizing silver nanoparticles (AgNPs) and essential oil nanoparticles (EoNPs) from E. benthamii. AgNPs were created by adding AgNO3 to an aqueous extract of E. benthamii leaves, indicated by a color change. EoNPs were formed by interfacial deposition of preformed polymer. The nanoparticles were analyzed for size, zeta potential and morphology using Zetasizer Nano® and Field Emission Gun - Scanning Electron Microscope (FEG-SEM). Cytotoxicity was evaluated in 3T3 fibroblasts using the MTT assay. The results showed a zeta potential of -20.5 ± 2.23 mV and an average size of 137.7 ± 17.25 nm, and decreased cell viability at concentrations of 6.25% to 50%. The EoNPs had an average diameter of 146.0 ± 6.71 nm, a zeta potential of -20.9 ± 0.854 mV, and stimulated fibroblast growth at lower concentrations. The study demonstrates the effective and eco-friendly synthesis of bioactive nanoparticles using E. benthamii extract and essential oil, highlighting their potential benefits in skincare.

Lutein, a potent carotenoid antioxidant, shows promise for anti-aging applications. However, its vulnerability to light, heat, and oxygen, coupled with poor water solubility, hinders skin penetration and bioavailability. Nanostructured systems offer a solution to enhance stability and permeation. Our objective was to develop, characterize, and assess the cytotoxicity and antioxidant activity of polymeric nanocapsules containing lutein, using poly(ɛ-caprolactone) (PCL). Nanocapsules were synthesized via preformed polymer interfacial deposition method and characterized using dynamic light scattering (DLS), electrophoretic mobility, and pH. Morphology was examined using field emission scanning electron microscopy (FESEM). X-ray diffraction (XRD) indicated the crystalline structures while Fourier-transform infrared spectra (FTIR) provided information on the chemical bonds between the drug and polymer. Antioxidant activity was measured using FRAP, DPPH, and ABTS assays, while cytotoxicity was evaluated on 3T3 fibroblasts. Lutein encapsulation within PCL nanocapsules yielded spherical particles around 300 nm, with low polydispersity and zeta potential exceeding -30 mV. The pH ranged from 4.57 ± 0.03 to 5.42 ± 0.065. XRD suggested molecular dispersion of the lutein and the polymer. FTIR demonstrated the absence of chemical bonds between lutein and PCL. Ambient and 4 °C temperatures preserved nanosystems' characteristics for 30 days. Enhanced antioxidant activity was observed in encapsulated lutein, shown by FRAP, DPPH, and ABTS assays. Results indicated that lutein nanoparticles exhibited good biocompatibility and no cytotoxicity at concentrations ranging from 61.87 μg/mL to 7.73 μg/mL. These findings emphasize the potential of lutein-loaded PCL nanocapsules for skin delivery, providing stability and antioxidant efficacy.

(1) Background: Blackberry seed oil (BSO), obtained from Rubus spp. Xavante cultivar via supercritical CO₂ extraction, contains bioactive lipids and antioxidants, but its cosmetic application is limited by poor solubility and stability. Nanoencapsulation with poly(ε-caprolactone) (PCL) can overcome these limitations. (2) Methods: BSO was characterized by UHPLC–ESI–Q-TOF–MS and incorporated into PCL nanocapsules (NCBSO) using the preformed polymer deposition method. Physicochemical properties, stability (at 4 °C, room temperature, and 37 °C for 90 days), cytotoxicity, and collagen production were assessed in human fibroblasts. (3) Results: NCBSO showed nanometric size (~267 nm), low polydispersity (PDI < 0.2), negative zeta potential (−28 mV), and spherical morphology confirmed by FE-SEM. The dispersion remained stable across all tested temperatures, preserving pH and colloidal properties. In particular, BSO and NCBSO at 100 µg.mL-1 significantly enhanced collagen production by 170% and 200%, respectively, compared to untreated cells (p < 0.01). Superior bioactivity was observed for NCBSO. No cytotoxic effects were achieved. (4) Conclusions: The nanoencapsulation of BSO into PCL nanocapsules ensured formulation stability and potentiated collagen production. NCBSO may be further used as a novel cosmeceutical for collagen-boosting skincare.

Nanoparticles, defined as materials with at least one dimension smaller than 100 nanometers, have increasingly been incorporated into cosmetic formulations, giving rise to the field of nanocosmetics. This narrative review examines regulatory frameworks and safety assessment strategies for nanocosmetics from a One Health perspective, considering their implications for human health, animal welfare, and environmental integrity. An overview of major classes of nanocarriers used in cosmetic products is presented, together with key physicochemical properties relevant to risk assessment. Current international regulatory approaches governing nanocosmetics are discussed, highlighting existing challenges, regulatory gaps, and the lack of global harmonization. Consumer safety and methodological evaluation strategies, including alternative testing methods, are critically addressed in the context of One Health principles. Overall, this review underscores the need for integrated, life-cycle-based regulatory and safety frameworks to support the responsible and sustainable development of nanocosmetics.