Confocal Raman spectroscopy coupled with in vitro permeation testing to study the effects of formalin fixation on the skin barrier function of reconstructed human epidermis.

Confocal Raman Spectroscopy is recognised as a potent tool for molecular characterisation of biological specimens. There is a growing demand for In Vitro Permeation Tests (IVPT) in the pharmaceutical and cosmetic areas, increasingly conducted using Reconstructed Human Epidermis (RHE) skin models. In this study, chemical fixation of RHE in 10 % Neutral Buffered Formalin for 24 h has been examined for storing RHE samples at 4 °C for up to 21 days.

Strat-M® positioning for skin permeation studies: A comparative study including EpiSkin® RHE, and human skin.

In the development and optimization of dermatological products, In Vitro Permeation Testing (IVPT) is pivotal for controlled study of skin penetration. To enhance standardization and replicate human skin properties reconstructed human skin and synthetic membranes are explored as alternatives. Strat-M® is a membrane designed to mimic the multi-layered structure of human skin for IVPT.

Label-Free Quantification of Nanoencapsulated Piperonyl Esters in Cosmetic Hydrogels Using Raman Spectroscopy.

Raman spectroscopy is a well-established technique for the molecular characterisation of samples and does not require extensive pre-analytical processing for complex cosmetic products. As an illustration of its potential, this study investigates the quantitative performance of Raman spectroscopy coupled with partial least squares regression (PLSR) for the analysis of Alginate nanoencapsulated Piperonyl Esters (ANC-PE) incorporated into a hydrogel. A total of 96 ANC-PE samples covering a 0.

Smart PEG-Block-PLA/PLA Nanosystems: Impact of the Characteristics of the Polymer Blend on the Redox Responsiveness.

Nanocarriers (NCs) were designed from three polymer blends (B1, B2 and B3) and investigated as smart drug delivery systems (SDDS). The blends are composed of a "smart" copolymer, where methoxy poly(ethylene glycol) and poly(lactic acid) are connected via a redox-responsive disulfide bond (mPEG-SS-PLA), and of a "conventional" polymer, poly(lactic acid) (PLA). They differ by mPEG-SS-PLA/PLA ratio and PLA molecular weight.

Efficiency of emulsifier-free emulsions in delivering caffeine and α-tocopherol to human skin.

Objective: Increasing consumer demand for natural and environmentally friendly products is driving the cosmetic industry to seek greener and safer processes. High-frequency ultrasound technology (HFUT) stabilizes emulsions without adding emulsifying surfactants (ES). In this work, the formulation characteristics of an HFUT-treated emulsion and a Reference emulsion were compared for both caffeine and α-tocopherol.

Estimating the Analytical Performance of Raman Spectroscopy for Quantification of Active Ingredients in Human .

Confocal Raman microscopy (CRM) has become a versatile technique that can be applied routinely to monitor skin penetration of active molecules. In the present study, CRM coupled to multivariate analysis (namely PLSR-partial least squares regression) is used for the quantitative measurement of an active ingredient (AI) applied to isolated (ex vivo) human (SC), using systematically varied doses of resorcinol, as model compound, and the performance is quantified according to key figures of merit defined by regulatory bodies (ICH, FDA, and EMA). A methodology is thus demonstrated to establish the limit of detection (LOD), precision, accuracy, sensitivity (SEN), and selectivity (SEL) of the technique, and the performance according to these key figures of merit is compared to that of similar established methodologies, based on studies available in literature.

Monitoring the water content in NADES extracts from spirulina biomass by means of ATR-IR spectroscopy.

Attenuated total reflectance-infrared spectroscopy (ATR-IR) coupled with partial least squares regression (PLSR) was evaluated as a rapid, label free and cost-effective tool to quantify water content in extracts obtained from spirulina wet biomass using a glucose glycerol natural deep eutectic solvent (NADES). NADESs are green, renewable and biodegradable solvents with unique properties outcompeting existing organic solvents, for instance, for plant or biomass extraction. The properties of NADESs depend critically on their water concentration, and therefore, it is essential to develop methods to monitor it, to ensure optimal extraction efficiency and experimental repeatability to achieve a better standardization of extraction protocols.

Confocal Raman Spectroscopic Imaging for Evaluation of Distribution of Nano-Formulated Hydrophobic Active Cosmetic Ingredients in Hydrophilic Films.

Film-forming systems are highly relevant to the topical administration of active ingredients (AI) to the body. Enhanced contact with the skin can increase the efficacy of delivery and penetration during prolonged exposure. However, after the evaporation of volatile solvents to form a thin film, the distribution of the ingredient should remain homogenous in order to ensure the effectiveness of the formula.

Comparison of Raman and attenuated total reflectance (ATR) infrared spectroscopy for water quantification in natural deep eutectic solvent.

Natural deep eutectic solvents (NADES) are ionic solutions, of great interest for extraction from biomass, biocatalysis, and nanoparticle synthesis. They are easily synthesised and eco-friendly, have low volatility and high dissolution power, and are biodegradable. However, water content in NADES is a critical parameter, affecting their optimal use and extraction efficiency.

Polymer-Based Smart Drug Delivery Systems for Skin Application and Demonstration of Stimuli-Responsiveness.

Progress in recent years in the field of stimuli-responsive polymers, whose properties change depending on the intensity of a signal, permitted an increase in smart drug delivery systems (SDDS). SDDS have attracted the attention of the scientific community because they can help meet two current challenges of the pharmaceutical industry: targeted drug delivery and personalized medicine. Controlled release of the active ingredient can be achieved through various stimuli, among which are temperature, pH, redox potential or even enzymes.

Freezing Weakens the Barrier Function of Reconstructed Human Epidermis as Evidenced by Raman Spectroscopy and Percutaneous Permeation.

The development and characterization of reconstructed human epidermis (RHE) is an active area of R&D. RHE can replace animal tissues in pharmaceutical, toxicological and cosmetic sciences, yielding scientific and ethical advantages. RHEs remain costly, however, due to consumables and time required for their culture and a short shelf-life.

Three-Step Synthesis of a Redox-Responsive Blend of PEG--PLA and PLA and Application to the Nanoencapsulation of Retinol.

Smart polymeric nanocarriers have been developed to deliver therapeutic agents directly to the intended site of action, with superior efficacy. Herein, a mixture of poly(lactide) (PLA) and redox-responsive poly(ethylene glycol)--poly(lactide) (PEG--PLA) containing a disulfide bond was synthesized in three steps. The nanoprecipitation method was used to prepare an aqueous suspension of polymeric nanocarriers with a hydrodynamic diameter close to 100 nm.

Raman mapping coupled to self-modelling MCR-ALS analysis to estimate active cosmetic ingredient penetration profile in skin.

Confocal Raman mapping (CRM) is a powerful, label free, non-destructive tool, enabling molecular characterization of human skin with applications in the dermo-cosmetic field. Coupling CRM to multivariate analysis can be used to monitor the penetration and permeation of active cosmetic ingredients (ACI) after topical application. It is presently illustrated how multivariate curve resolution alternating least squares (MCR-ALS) can be applied to detect and semi-quantitatively describe the diffusion profile of Delipidol, a commercially available slimming ACI, from Raman spectral maps.

Nanovectorized Microalgal Extracts to Fight and Biofilms: Impact of Dual-Species Conditions.

Biofilm-related infections are a matter of concern especially because of the poor susceptibility of microorganisms to conventional antimicrobial agents. Innovative approaches are needed. The antibiofilm activity of extracts of cyanobacteria , rich in free fatty acids, as well as of extract-loaded copper alginate-based nanocarriers, were studied on single- and dual-species biofilms of and .

Quantification of low-content encapsulated active cosmetic ingredients in complex semi-solid formulations by means of attenuated total reflectance-infrared spectroscopy.

Attenuated total reflectance-infrared (ATR-IR) spectroscopy is a robust tool for molecular characterisation of matter. Applied to semi-solid formulations, it enables rapid and reliable data collection without pre-analytical requirements. Based on nano-encapsulated Omegalight®, a skin-lightening active cosmetic ingredient (ACI), incorporated in a hydrogel, it is first demonstrated that, despite the high water content and the chemical complexity of the samples (i.

gH625 Cell-Penetrating Peptide Promotes the Endosomal Escape of Nanovectorized siRNA in a Triple-Negative Breast Cancer Cell Line.

The use of small interfering RNA (siRNA) to regulate oncogenes appears as a promising strategy in the context of cancer therapy, especially if they are vectorized by a smart delivery system. In this study, we investigated the cellular trafficking of a siRNA nanovector (called CS-MSN) functionalized with the cell-penetrating peptide gH625 in a triple-negative breast cancer model. With complementary techniques, we showed that siRNA nanovectors were internalized by both clathrin- and caveolae-mediated endocytosis.

Versatile electrostatically assembled polymeric siRNA nanovectors: Can they overcome the limits of siRNA tumor delivery?

The application of small interfering RNA (siRNA) cancer therapeutics is limited by several extra- and intracellular barriers including the presence of ribonucleases that degrade siRNA, the premature clearance, the impermeability of the cell membrane, or the difficulty to escape endo-lysosomal degradation. Therefore, several delivery systems have emerged to overcome these limitations and to successfully deliver siRNA to the tumor site. This review is focused on polymer-based siRNA nanovectors which exploit the negative charge of siRNA, representing a major challenge for siRNA delivery, to their advantage by loading siRNA via electrostatic assembly.

Formulation and in vitro evaluation of a siRNA delivery nanosystem decorated with gH625 peptide for triple negative breast cancer theranosis.

The development of an efficient small interfering RNA (siRNA) delivery system has held scientists interest since the discovery of the RNA interference mechanism (RNAi). This strategy gives hope for the treatment of many severe diseases. Herein, we developed hybrid nanovectors able to deliver siRNA to triple negative breast cancer cells.

ATR-IR coupled to partial least squares regression (PLSR) for monitoring an encapsulated active molecule in complex semi-solid formulations.

Attenuated Total Reflectance-Infrared (ATR-IR) spectroscopy holds great promise for industrial applications as a quality control tool for complex galenic formulations. Although the technique is often promoted for the molecular information it delivers in a label free and cost effective fashion, other advantages can emerge compared to the gold standard analytical tools such as liquid chromatography coupled to mass spectrometry. The present study demonstrates how ATR-IR measurements enable accurate quantitative analysis of an active cosmetic ingredient such as Omegalight® encapsulated in a complex alginate based nano-capsule.

Confocal Raman spectroscopic imaging for in vitro monitoring of active ingredient penetration and distribution in reconstructed human epidermis model.

Topically applied active cosmetic ingredients (ACI) or active pharmaceutical ingredients (API) efficacy is directly related to their efficiency of penetration in the skin. In vitro reconstructed human epidermis surrogate models offer in vivo like skin samples for transdermal studies. Using Delipidol®, an ACI currently used in the cosmetics industry, the capabilities to deliver accurate distribution maps and penetration profiles of this molecule by means of confocal Raman spectroscopic imaging have been demonstrated.

Quantitative analysis of curcumin-loaded alginate nanocarriers in hydrogels using Raman and attenuated total reflection infrared spectroscopy.

Core-shell nanocarriers are increasingly being adapted in cosmetic and dermatological fields, aiming to provide an increased penetration of the active pharmaceutical or cosmetic ingredients (API and ACI) through the skin. In the final form, the nanocarriers (NC) are usually prepared in hydrogels, conferring desired viscous properties for topical application. Combined with the high chemical complexity of the encapsulating system itself, involving numerous ingredients to form a stable core and quantifying the NC and/or the encapsulated active without labor-intensive and destructive methods remains challenging.

Lipid-based submicron capsules as a strategy to include high concentrations of a hydrophobic lightening agent in a hydrogel.

Objective: This study aimed at increasing the concentration of a hydrophobic lightening agent, Omegalight , in a hydrophilic cosmetic product by means of encapsulation in lipid-based submicron capsules. The core of these capsules is entirely made of the commercial lightening agent.

Methods: Lipid-based encapsulation systems (LNC) were prepared by the PIT method.