Polymer-based eye drops are the most used drug delivery system to treat dry eye disease (DED). Therefore, the mucoadhesion between the polymer and the ocular mucin is crucial to ensure the efficacy of the treatment. In this context, the present study aimed to evaluate the potential use of in vitro methods to study the mucoadhesion of eye drop solutions and, specifically to evaluate the efficacy of two hyaluronic acid-based formulations (HA), HA 0.15% and 0.30% (w/v) to treat DED. Rheology methods and zeta potential determination were used to study the mucoadhesive properties of both eye drop solutions. All results indicated that interactions occurred between the mucin and the HA, being stronger with HA 0.30%, due to the physical entanglements and hydrogen bounding. In vitro tests on ARPE-19 cell line were performed using a 2D and a 3D dry eye model and the results have shown that pre-treated cells with HA showed a morphology more similar to the hydrated cells in both products, with a high survival rate. The in vitro techniques used in this study have been shown to be suitable to evaluate and predict mucoadhesive properties and the efficacy of the eye drops on relief or treatment of DED. The results obtained from these methods may help in inferring possible in vivo effects.

Quercus Suber Bark from Quercus suber L. is a natural, renewable and biodegradable biomaterial with multifunctional proprieties. In this study, we used it as solid particles to stabilize a Pickering emulsion. The main goal was to produce an optimized topical formulation using biocompatible organic particles as stabilizers of the emulsion instead of the common surfactants, whilst benefiting from Quercus suber L. proprieties. In this work, a Quality by Design (QbD) approach was successfully applied to the production of this emulsion. A screening design was conducted, identifying the critical variables of the formula and process, affecting the critical quality attributes of the emulsion (droplet size distribution). The optimization of the production was made through the establishment of the design space. The stability was also investigated during 30 days, demonstrating that Quercus Suber Bark-stabilized emulsions are stable since the droplet size distribution lowers. In vitro studies were performed to assess antioxidant and antiaging efficacy, which revealed that the formulation had indeed antioxidant proprieties. A physicochemical characterization demonstrated that the formulation presents a shear-thinning fluid, ideal for topical administration. The in vivo compatibility study confirmed that the final formulation is not skin irritant, being safe for human use. A sensorial analysis was also performed, using a simple sensory questionnaire, revealing very positive results. Thus, the use of Quercus Suber Bark particles as a multifunctional solid ingredient contributed to achieve a stable, effective and innovative Pickering emulsion with a meaningful synergistic protection against oxidative stress.

Essential oils (EOs) and hydrolates (Hds) are natural sources of biologically active ingredients with broad applications in the cosmetic industry. In this study, nationally produced (mainland Portugal and Azores archipelago) EOs (11) and Hds (7) obtained from forest logging and thinning of Eucalyptus globulus, Pinus pinaster, Pinus pinea and Cryptomeria japonica, were chemically evaluated, and their bioactivity and sensorial properties were assessed. EOs and Hd volatiles (HdVs) were analyzed by GC-FID and GC-MS. 1,8-Cineole was dominant in E. globulus EOs and HdVs, and α- and β-pinene in P. pinaster EOs. Limonene and α-pinene led in P. pinea and C. japonica EOs, respectively. P. pinaster and C. japonica HVs were dominated by α-terpineol and terpinen-4-ol, respectively. The antioxidant activity was determined by DPPH, ORAC and ROS. C. japonica EO showed the highest antioxidant activity, whereas one of the E. globulus EOs showed the lowest. Antimicrobial activity results revealed different levels of efficacy for Eucalyptus and Pinus EOs while C. japonica EO showed no antimicrobial activity against the selected strains. The perception and applicability of emulsions with 0.5% of EOs were evaluated through an in vivo sensory study. C. japonica emulsion, which has a fresh and earthy odour, was chosen as the most pleasant fragrance (60%), followed by P. pinea emulsion (53%). In summary, some of the studied EOs and Hds showed antioxidant and antimicrobial activities and they are possible candidates to address the consumers demand for more sustainable and responsibly sourced ingredients.

The coronavirus disease 2019 (COVID‐19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) enforced the use of hand sanitation and of personal protective equipment, such as masks and visors, especially by health‐care professionals, but also by the general public. However, frequent hand sanitation and the prolonged and continuous use of personal protective equipment are responsible for constant frictional and pressure forces on skin causing lesions, the most reported being acne, facial itching, dryness, and rash. Thus, it is important to find measures to prevent skin lesions, in order to improve the quality of life of health‐care professionals and of the general public. This article gathers the current information regarding measures to prevent human to human transmission of COVID‐19, reviews the most common skin lesions caused by the use of hand sanitizers and different types of personal protective equipment, and the possible preventive measures that can be used on a daily basis to minimize the risk of developing skin‐related pathologies. Daily skin care routines and the incorporation of a dressing between the skin and the personal protective equipment to serve as a protective barrier are some of the applied measures. Moisturizers and dressings improve the skin's ability to respond to constant aggressions. Lastly, the need for additional studies to evaluate the lubrication properties of different types of dressings is discussed. The understanding of what kind of dressing is more suitable to prevent pressure injuries is crucial to promote healthy skin and wellbeing during pandemic times.

The use of mineral water for therapeutic purposes has varied from century to century and from country to country. Its effectiveness depends on the individual experiences of the population and their cultural traditions. Usually, the waters recommended for dermatological treatment are hot springs that contain sulfur or more recently, silicon. The mechanisms by which mineral waters actuate in dermatological disorders are still not clear but it is believed that they involve thermal, mechanical, chemical, immunologic, and anti-oxidant reactions and enzymatic activity. The aim of this study is to characterize the thermal waters of Monfortinho, one of the oldest Portuguese spas, their potential use for the preparation of dermatological formulations (creams), and their effectiveness on the treatment of skin disorders (psoriasis and eczema). To accomplish this, cream formulations with different contents of thermal water were developed. The formulations were characterized in terms of thermal water analysis and physicochemical properties and their effects were studied by skin biometrics in adults (mean age of 54.3 years old) through skin hydration evaluation and evaluated in clinical studies on 22 patients with psoriasis and eczema. The results showed that all the formulations improved the skin hydration and have beneficial effects in relieving the symptoms of psoriasis and other disorders, but no significant differences were observed when thermal water was used (compared to laboratory ultra-pure water).