Raquel Allen Garcia Barbeto Siqueira

High-energy methods dominate the development of lipid nanoparticles but often require specialized equipment that increases production costs. Low-energy approaches, particularly those free of organic solvents, offer a promising alternative. This study aimed to obtain nanostructured lipid carriers (NLCs) using a solvent-free, low-energy process combining microemulsification and phase inversion. Cetearyl alcohol and PEG-40 hydrogenated castor oil were selected as the solid lipid and surfactant, respectively; the formulation and process were optimized through a Box–Behnken Design. Incorporation of the ionic surfactant extended colloidal stability, while the poloxamer in the aqueous phase enhanced steric stabilization. Resveratrol was efficiently encapsulated (E.E. = 98%), contributing to reduced particle size (291 nm), improved homogeneity (PDI = 0.25), and positive surface charge (+43 mV). Scale-up yielded stable particles carrying resveratrol with a mean size of 507 nm, PDI = 0.24, and ZP = +52 mV. The optimized formulation remained stable for 90 days at 8 °C. In vitro release demonstrated a sustained and controlled release profile, with significantly lower resveratrol release compared to the free compound. Thermal analysis confirmed drug incorporation within the lipid matrix, while transmission electron microscopy (TEM) revealed spherical particles (~200 nm) and SAXS indicated a nanostructure of ~50 nm. Overall, this study demonstrates that solvent-free, low-energy processing can produce stable and scalable NLC formulations, successfully encapsulating resveratrol with favorable physicochemical properties and controlled release behavior. These findings highlight a simple, cost-effective strategy for developing lipid-based nanocarriers with potential applications in drug delivery.

High-energy methods dominate the development of lipid nanoparticles but often require specialized equipment that increases production costs. Low-energy approaches, particularly those free of organic solvents, offer a promising alternative. This study aimed to obtain nanostructured lipid carriers (NLC) using a solvent-free, low-energy process combining microemulsification and phase inversion. Cetearyl alcohol and PEG-40 hydrogenated castor oil were selected as solid lipid and surfactant, respectively, the formulation and process were optimized through a Box–Behnken Design. Incorporation of ionic surfactant extended colloidal stability, while poloxamer in the aqueous phase enhanced steric stabilization. Resveratrol was efficiently encapsulated (E.E. = 98%), contributing to reduced particle size (291 nm), improved homogeneity (PDI = 0.25), and positive surface charge (+43 mV). Scale-up yielded stable particles carrying resveratrol with mean size of 507 nm, PDI = 0.24, and ZP = +52 mV. The optimized formulation remained stable for 90 days at 8 °C. In vitro release demonstrated a sustained and controlled release profile, with significantly lower resveratrol release compared to the free compound. Thermal analysis confirmed drug incorporation within the lipid matrix, while transmission electron microscopy (TEM) revealed spherical particles (~200 nm) and SAXS indicated a nanostructure of ~50 nm. Overall, this study demonstrates that solvent-free, low-energy processing can produce stable and scalable NLC formulations, successfully encapsulating resveratrol with favorable physicochemical properties and controlled release behavior. These findings highlight a simple, cost-effective strategy for developing lipid-based nanocarriers with potential applications in drug delivery.

The human skin microbiome, defined as a multifaceted ecosystem comprising bacteria, fungi, viruses, and mites, plays a pivotal role in maintaining skin homeostasis and regulating immune responses. In recent years, an increasing amount of evidence has illuminated the considerable influence exerted by microbiomes on the pathophysiology of dermatological ailments. This review provides a comprehensive synthesis of contemporary findings concerning the microbiome’s role in acne, aging, hyperpigmentation, and hair disorders, while also addressing the emerging concept of the gut–skin axis and how it could interfere in these skin disorders. Alterations in microbial composition, referred to as dysbiosis, have been associated with inflammatory processes and barrier dysfunction, thereby contributing to the severity and chronicity of diseases. Distinct microbial profiles have been identified as correlating with specific skin conditions. For instance, variations in Cutibacterium acnes phylotypes have been associated with the development of acne, whereas alterations in Corynebacterium and Staphylococcus species have been linked to the processes of aging and pigmentation patterns. Furthermore, the composition of the microbiome is examined in relation to its impact on cosmetic outcomes. It also engages with increasing interest in the modulation of microbiota through the topical application of bioactive compounds. The incorporation of prebiotics, probiotics, and postbiotics into cosmetic formulations constitutes a novel strategy aimed at enhancing skin health. In the domain of dermatological therapies, postbiotics have emerged as a significant class of substances, particularly due to their remarkable stability, safety, and immunomodulatory properties. These characteristics position them as promising candidates for incorporation into dermatological treatments. Recent studies have underscored the significance of microbiome-informed strategies within the domains of therapeutic and preventive dermatology, emphasizing the potential of such approaches to positively influence patient outcomes. As our understanding of this field continues to evolve, skin microbiomes are poised to emerge as a pivotal area of focus in the realm of personalized skin care and treatment. This development presents novel and innovative approaches for the management of skin conditions, characterized by enhanced specificity and efficacy.

Metagenomic studies have provided deeper insights into the complex interactions between the skin and its microbiota. However, limited research has been conducted on the skin microbiota of Brazilian women. Given that Brazil ranks as the fourth-largest consumer of cosmetics worldwide, the development of new tools to analyze skin microbiota is crucial for formulating cosmetic products that promote a healthy microbiome. Skin samples were analyzed using the Illumina platform. Biometrology assessments were applied. The results showed pH variations were more pronounced in the older age group, along with higher transepidermal water loss values. Metagenomic analysis showed a predominance of Actinobacteria (83%), followed by Proteobacteria (7%), Firmicutes (9%) and Bacteroidetes (1%). In the older group (36–45 years old), an increase in Actinobacteria (87%) was observed and a decrease in Proteobacteria (6%). Moreover, the results differ from the international literature, since an increase in proteobacteria (13.9%) and a decrease in actinobacteria (46.7%) were observe in aged skin. The most abundant genus identified was Propionibacterium (84%), being the dominant species. Interestingly, previous studies have suggested a decline in Cutibacterium abundance with aging; although there is no significant difference, it is possible to observe an increasing trend in this genus in older skin. These studies can clarify many points about the skin microbiota of Brazilian women, and these findings could lead to the development of new cosmetics based on knowledge of the skin microbiome.

Skin lipids are essential components that play crucial roles in maintaining the skin barrier, preventing transepidermal water loss, and protecting against external agents. The specific composition of lipids may vary according to factors, such as age, diet, and environmental conditions. They are found predominantly in the stratum corneum, the outermost layer of the epidermis, with lipids originating from epidermal lipids and also from the sebaceous glands. The diversity of lipids, including ceramides, cholesterol, free fatty acids, sphingolipids, phospholipids, triglycerides, and waxes, reflects the complexity of their functions. Understanding the properties and biosynthesis of skin lipids is fundamental for advancing dermatology, developing treatments for various skin conditions, and maintaining the integrity of the skin barrier. Skin microbiome could affect skin lipid composition, and this topic has yet to be completely understood. This literature review aims to understand the properties of lipids found in the skin, the function and importance of fatty acids for skin maintenance and integrity, and their correlations that influence homeostasis: pH, the role of lipids in the microbiota, and finally, daily care practices that can influence the health of the skin and also the microbiome.