Skin Irritation Potential Research Articles

Assessment of antibacterial properties and skin irritation potential of anodized aluminum impregnated with various quaternary ammonium

The importance of the inert environment in the transmission of pathogens has been reassessed in recent years. To reduce cross-contamination, new biocidal materials used in high touch surfaces (e.g., stair railings, door handles) have been developed. However, their impact on skin remains poorly described. The present study aimed to evaluate the antibacterial properties and the risk of skin irritation of two materials based on hard-anodized aluminum (AA) impregnated with quaternary ammonium compound solutions (QAC#1 or QAC#2). The QAC#1 or QAC#2 solutions vary in composition, QAC#2 being free of dioctyl dimethyl ammonium chloride (Dio-DAC) and octyl decyl dimethyl ammonium chloride (ODDAC). Unlike AA used as a control, both AA-QAC#1 and AA-QAC#2 had excellent and rapid antibacterial efficacy, killing 99.9 % of Staphylococcus aureus and Escherichia coli bacteria, in 15 s and 1 min, respectively. The impregnation solutions (QAC#1 and QAC#2) did not show any skin sensitizing effect on transformed human keratinocytes. Nevertheless, these solutions as well as the materials (AA-QAC#1, AA-QAC#2), and the liquid extracts derived from them, induced a very rapid cytotoxicity on L929 murine fibroblasts (>70 % after 1 h of contact) as shown by LDH, MTS and neutral red assays. This cytotoxicity can be explained by the fast QACs release occurring when AA-QAC#1 and AA-QAC#2 were immersed in aqueous medium. To overcome the limitation of assays based on liquid condition, an in vitro skin irritation assay on reconstructed human epidermis (RHE) was developed. The effect of the materials upon their direct contact with the epidermis grown at the liquid-air interface was determined by evaluating tissue viability and quantifying interleukin-1 alpha (IL-1α) which is released in skin during injury or infection. AA-QAC#1 induced a significant decrease in RHE viability, close to OECD and ISO 10993-10 acceptability thresholds and enhanced the pro-inflammatory IL-1α secretion compared with AA-QAC#2. Finally, these results were corroborated by in vivo assays on mice using erythema and edema visual scores, histological observations, and epidermal thickness measurement. AA had no effect on the skin, while a stronger irritation was induced by AA-QAC#1 compared with AA-QAC#2. Hence, these materials were classified as moderate and slight irritants, respectively. In summary, this study revealed that AA-QAC#2 without Dio-DAC and ODDAC could be a great candidate for high touch surface applications, showing an extremely effective and rapid bactericidal activity, without inducing adverse effects for skin tissue.

Carboxylated nanocellulose for wound healing applications – Increase of washing efficiency after chemical pre-treatment and stability of homogenized gels over 10 months

To commercialize a biomedical product as a medical device, reproducibility of production and time-stability are important parameters. Studies of reproducibility are lacking in the literature. Additionally, chemical pre-treatments of wood fibres to produce highly fibrillated cellulose nanofibrils (CNF) seem to be demanding in terms of production efficiency, being a bottleneck for industrial upscaling. In this study, we evaluated the effect of pH on the dewatering time and washing steps of 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO)-mediated oxidized wood fibres when applying 3.8 mmol NaClO/g cellulose. The results indicate that the method does not affect the carboxylation of the nanocelluloses, and levels of approximately 1390 μmol/g were obtained with good reproducibility. The washing time of a Low-pH sample was reduced to 1/5 of the time required for washing a Control sample. Additionally, the stability of the CNF samples was assessed over 10 months and changes were quantified, the most pronounced were the increase of potential residual fibre aggregates, reduction of viscosity and increase of carboxylic acid content. The cytotoxicity and skin irritation potential were not affected by the detected differences between the Control and Low-pH samples. Importantly, the antibacterial effect of the carboxylated CNFs against S. aureus and P. aeruginosa was confirmed.

Assessment of eight feed additives consisting of Lactiplantibacillus plantarumCNCM I-3235, L. plantarumCNCM I-3736/DSM 11672, Pediococcus acidilacticiCNCMI-3237, P. acidilacticiCNCM I-4622/DSM 11673, Pediococcus pentosaceusNCIMB 12455, Acidipropionibacterium acidipropioniciCNCM I-4661, Lentilactobacillus buchneriNCIMB 40788/CNCM I-4323 and L. buchneriNCIMB 40788/CNCM I-4323 plus Lentilactobacillus hilgardiiCNCM I-4785 for all animal species for the renewal of their authorisation (Danstar Ferment AG).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the assessment of the application for renewal of eight technological additives, including two Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) [CNCM I-3235 and CNCM I-3736/ DSM 11672], two Pediococcus acidilactici [CNCM I-3237 and CNCM I-4622/DSM 11673], one Pediococcus pentosaceus [NCIMB 12455], one Acidipropionibacterium acidipropionici (formerly Propionibacterium acidipropionici) [CNCM I-4661], one Lentilactobacillus buchneri (formerly Lactobacillus buchneri) [NCIMB 40788/ CNCM I-4323], and the additive composed by the two active agents L. buchneri NCIMB 40788/ CNCM I-4323 and Lentilactobacillus hilgardii (formerly Lactobacillus hilgardii) CNCM I-4785, as silage additives for use in forage for all animal species. The applicant has provided evidence that the additives currently on the market comply with the existing conditions of authorisation. There is no new evidence that would lead the FEEDAP Panel to reconsider its previous conclusions. Thus, the Panel concluded that the additives remain safe for all animal species, consumers and the environment under the authorised conditions of use. Regarding user safety, the additives should be considered as respiratory sensitisers. In the absence of data, no conclusions could be drawn on the skin sensitisation, and skin and eye irritancy potential of the additives, with the exception for Pediococcus acidilactici CNCM I-4622/DSM 11673 (for which the Panel concluded that is non-irritant to skin and eyes). There is no need for assessing the efficacy of the additives in the context of the renewal of the authorisation.

Safety and efficacy of a feed additive consisting of vitamin B2 (riboflavin) produced by Bacillus subtilisCGMCC 13326 for all animal species (Kempex Holland B.V.).

Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) of EFSA was asked to deliver a scientific opinion on the safety and efficacy of vitamin B2 (riboflavin) produced by Bacillus subtilis CGMCC 13326 as a nutritional feed additive for all animal species. The additive is produced by a genetically modified production strain. Although the production strain harbours some genes coding for resistance to antimicrobials, viable cells and DNA of the production strain were not detected in the final product. Therefore, the use of B. subtilis CGMCC 13326 to produce vitamin B2 does not raise safety concerns. The use of riboflavin 80% produced by B. subtilis CGMCC 13326 in animal nutrition does not represent a safety concern for the target species, consumers and for the environment. In the absence of data, the FEEDAP Panel cannot conclude on the potential skin and eye irritation or potential toxicity by inhalation of the additive under assessment. Riboflavin is a known photosensitiser which may elicit skin and eye photoallergic reactions. The additive under assessment is effective in covering the animals' requirements of vitamin B2 when administered via feed.

Machine-learning based prediction models for assessing skin irritation and corrosion potential of liquid chemicals using physicochemical properties by XGBoost.

The online version contains supplementary material available at 10.1007/s43188-022-00168-8.

Investigating the surfactant antagonism with the Open Source Reconstructed Epidermis (OS-Rep) model

Under the current EU chemicals legislation, in vitro test methods became the preferred methods to identify and classify the skin irritation potential of chemicals and mixtures. Among these, especially in vitro skin models are widely used. For surfactants, a well-known group of typically irritating chemicals, it is a long-standing experience that the irritation potential of a mixture of surfactants is typically lower than the irritation potential of the single surfactants, an effect usually described as surfactant antagonism. In order to evaluate if this effect can be observed in skin model systems as well, the irritation potential of the surfactants and of their mixtures was determined in the Open Source Reconstructed Epidermis (OS-REp) models. Combinations of sodium dodecyl sulfate or linear alkylbenzene sulfonate with cocoamidopropyl betain and alkyl polyglycosid, respectively, resulted in a clear decrease of the irritation potential compared to the irritation exerted by the single surfactants. The effect appeared to be primarily driven by the mixture's lower ability to damage the skin model's barrier, as shown by a reduced fluorescein permeation.

Cosmetics regulations and standardization guidelines

Cosmetics are products used for enhancing or maintaining the appearance of the human body. They include skincare, haircare, fragrances, and personal hygiene products. While cosmetics can provide various benefits, they may also pose risks to consumers’ health and safety. As a result, many countries have established regulatory bodies to ensure the safety and efficacy of cosmetic products. Regulatory bodies are responsible for setting and enforcing standards for cosmetic products to protect consumers from potential harm. They evaluate the safety and effectiveness of ingredients used in cosmetics and establish guidelines for labeling, advertising, and packaging. Some of the major regulatory bodies that oversee cosmetics include the US Food and Drug Administration, the European Commission, and Health Canada. Regulatory bodies typically require cosmetic manufacturers to conduct safety assessments on their products and ingredients before they can be marketed to consumers. These assessments involve evaluating the potential toxicity, skin irritation, and other potential risks associated with the product or ingredient. Regulatory bodies also conduct postmarket surveillance to monitor adverse reactions and to ensure that products continue to meet safety and quality standards. Furthermore, regulatory bodies play a crucial role in ensuring that cosmetics are safe and effective for consumers. The regulations and guidelines they establish help to protect consumers from potential health risks associated with cosmetic products. The important regulatory frameworks governing cosmetic and herbal cosmetic products in various areas and nations have been briefly summarized in this chapter. It is crucial to follow these rules to guarantee product safety and safeguard customer interests. Companies need to keep aware as the cosmetics industry develops and reacts to the shifting regulatory environment.

Toxicology assessment of manganese oxide nanomaterials with enhanced electrochemical properties using human in vitro models representing different exposure routes

In the present study, a comparative human toxicity assessment between newly developed Mn3O4 nanoparticles with enhanced electrochemical properties (GNA35) and their precursor material (Mn3O4) was performed, employing different in vitro cellular models representing main exposure routes (inhalation, intestinal and dermal contact), namely the human alveolar carcinoma epithelial cell line (A549), the human colorectal adenocarcinoma cell line (HT29), and the reconstructed 3D human epidermal model EpiDerm. The obtained results showed that Mn3O4 and GNA35 harbour similar morphological characteristics, whereas differences were observed in relation to their surface area and electrochemical properties. In regard to their toxicological properties, both nanomaterials induced ROS in the A549 and HT29 cell lines, while cell viability reduction was only observed in the A549 cells. Concerning their skin irritation potential, the studied nanomaterials did not cause a reduction of the skin tissue viability in the test conditions nor interleukin 1 alpha (IL- 1 α) release. Therefore, they can be considered as not irritant nanomaterials according to EU and Globally Harmonized System of Classification and Labelling Chemicals. Our findings provide new insights about the potential harmful effects of Mn3O4 nanomaterials with different properties, demonstrating that the hazard assessment using different human in vitro models is a critical aspect to increase the knowledge on their potential impact upon different exposure routes.

Mussel-inspired poly(hydroxyethyl acrylate-co-itaconic acid)-catechol/hyaluronic acid drug-in-adhesive patches for transdermal delivery of ketoprofen

This research aimed to create new hydrophilic drug-in-adhesive patches for transdermal drug delivery. Poly(hydroxyethyl acrylate-co-itaconic acid)-catechol (PHI-cat) and hyaluronic acid (HA) were used as main components in the pressure-sensitive adhesive. Citric acid and aluminium hydroxide were exploited as crosslinking agents and ketoprofen was employed as a model delivering compound. The adhesive performance, physicochemical properties, drug-polymer interaction, drug crystallization, drug content, drug permeation through the skin, and coordination polymer network of the patches were investigated. In addition, skin irritation and adhesion potential in human subjects were assessed. Due to the ability of catechol groups to form interaction with the skin tissue, the patches containing PHI-cat and HA offered a considerably greater adhesion ability to human skin compared with the patches without catechol and commercial patches. Furthermore, the patches had good physical and chemical stability. Therefore, these catechol-functionalized patches may be potential transdermal drug delivery systems with excellent adhesive properties for the delivery of a drug through the skin.

Nanocrystal-Based Topical Gels for Improving Wound Healing Efficacy of Curcumin

Topical curcumin shows poor local availability because of its low aqueous solubility and inadequate tissue absorption. Curcumin nanocrystals were prepared by sonoprecipitation followed by lyophilization to improve surface area and solubility. The formulation was optimized by the Design of Experiment (DoE) approach. The nanocrystals were characterized for particle size, zeta potential, polydispersity index, scanning electron microscopy (SEM), powder x-ray diffraction (PXRD), practical yield and in vitro drug release studies. The nanocrystal-incorporated gel was evaluated for drug content, ex vivo permeation, in vivo skin irritation, and in vivo wound healing activity. Time of sonication and amplitude influenced the optimization of curcumin nanocrystals, but the effect of stabilizer concentrations was not significant beyond 0.5% w/w. SEM images of curcumin nanocrystals revealed irregular and plate-shaped particles with rough surfaces. PXRD patterns of curcumin nanocrystals showed low crystallinity compared to unprocessed curcumin powder. An in vitro drug release study demonstrated significant improvement in the percentage cumulative drug release in the form of nanocrystals compared to the unprocessed curcumin, and the release profile exhibited first-order kinetics. Curcumin nanocrystal gel showed 93.86% drug content and was free of skin irritation potential. Excision wound healing activity in albino rats showed that the curcumin nanocrystal gel exhibited significantly faster wound contraction than curcumin powder-incorporated gel.

Evaluation of skin-irritancy potential of a skin ointment containing the essential oil of ocimum sanctum l (Basil/Thulasi) leaves in Wistar albino rats

Skin irritant potential of a skin ointment containing 4% essential oil extracted from the Ocimum sanctum L. (Basil/Thulassi) leaves was evaluated on the hair clipped skin of female Wistar albino rats. The calculated Primary Irritation Index was ‘0” and it falls under the category of “negligible irritant.

Design and development of tranexamic acid loaded film-forming gel to alleviate melasma.

Melasma is a skin condition that causes increased epidermal pigmentation, enlarged melanocytes, increased melanosomes, solar elastosis, dermal blood vessels, and, occasionally, perivascular lymph histiocytic infiltrates. To develop the film-forming gel to alleviate melasma. Tranexamic acid was used as a model drug to evaluate the suitability of formulation to prevent symmetric hyperpigmentation. FFG is a hydrophilic polymeric cross-linked system loaded with an active moiety. Nine different formulations of 2% TXA were formulated using polyvinyl alcohol and hydroxypropyl methylcellulose 50 cP as film-forming polymers. Sodium carboxymethylcellulose, methylcellulose, and carbopol were used as gelling agents. F7, F8, and F9 showed shorter DT, that is, 11, 8, and 12 min, respectively. The folding endurance of F7, F8, and F9 was >100 folds, and the pH of F7, F8, and F9 was >6. Among three formulations, F8 was further analyzed for in vitro drug diffusion, which showed >95% drug diffusion within 48 h. In vivo, the skin irritation potential of F8 was estimated using BAL/C mice, which confirmed the absence of skin irritation. From the obtained results, we conclude that the FFG can be a strategic attempt to deliver the cosmeceutical drugs like TXA to alleviate Melasma with improved sustainability of the drug.

The potential use of kraft lignins as natural ingredients for cosmetics: Evaluating their photoprotective activity and skin irritation potential

The cosmetics market has recently undergone changes as consumers increasingly seek sustainable products. In this context, agro-derived lignins have the potential for cosmetics applications. Thus, this study investigated the photoprotective activity and skin irritation potential (OECD TG 439 with SkinVitro-RHE, an in-house reconstructed human epidermis (RHE) model) of a kraft lignin (LE) and two LE-derived lignins modified by enzymatic reactions to achieve higher molecular weight (Mw) (R1: intermediate Mw and E60: highest Mw). Results showed that LE and R1 lignins present adequate photoprotective activity with averages Sun Protection Factor (SPF) of 33.8 ± 0.02 and 22.7 ± 0.04, respectively. The E60 also present adequate SPF (22.4 ± 0.2); however, due to its poor solubility, this lignin has potential application as a physical filter. In terms of safety, these lignins did not cause skin irritation or cellular and structural damage to the epidermis. Additionally, using an analysis based on the autofluorescence feature of lignin, no sign of the tested lignins was found in exposed RHE models, indicating that these three lignins did not penetrate the skin. Altogether, the results indicate a promising application of kraft lignins for sunscreen products regarding safer alternatives and product sustainability. Also, the SkinVitro-RHE showed to be a good model for evaluating the skin irritation potential of substances, including natural cosmetic ingredients.

Use of Retinoids in Topical Antiaging Treatments: A Focused Review of Clinical Evidence for Conventional and Nanoformulations.

Nowadays, numerous skincare routines are used to rejuvenate aging skin. Retinoids are one of the most popular ingredients used in antiaging treatments. Among the representatives of retinoids, tretinoin is considered the most effective agent with proven antiaging effects on the skin and can be found in formulations approved as medicines for topical treatment of acne, facial wrinkles, and hyperpigmentation. Other retinoids present in topical medicines are used for various indications, but only tazarotene is also approved as adjunctive agent for treatment of facial fine wrinkling and pigmentation. The most commonly used retinoids such as retinol, retinaldehyde, and retinyl palmitate are contained in cosmeceuticals regulated as cosmetics. Since clinical efficacy studies are not required for marketing cosmetic formulations, there are concerns about the efficacy of these retinoids. From a formulation perspective, retinoids pose a challenge to researchers as a result of their proven instability, low penetration, and potential for skin irritation. Therefore, novel delivery systems based on nanotechnology are being developed to overcome the limitations of conventional formulations and improve user compliance. In this review, the clinical evidence for retinoids in conventional and nanoformulations for topical antiaging treatments was evaluated. In addition, an overview of the comparison clinical trials between tretinoin and other retinoids is presented. In general, there is a lack of evidence from properly designed clinical trials to support the claimed efficacy of the most commonly used retinoids as antiaging agents in cosmeceuticals. Of the other retinoids contained in medicines, tazarotene and adapalene have clinically evaluated antiaging effects compared to tretinoin and may be considered as potential alternatives for antiaging treatments. The promising potential of retinoid nanoformulations requires a more comprehensive evaluation with additional studies to support the preliminary findings.

Safety and efficacy of a feed additive consisting of carmine for cats and dogs (Mars Petcare GMbH).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the re‐evaluation of the safety and efficacy of carmine (sensory additive, functional group: colourants – substances that add or restore colour in feeds) for cats and dogs. The additive consists of aluminium lakes of carminic acid (carmines), which are complexes of aluminium and carminic acid. Carminic acid, produced from the female insect Dactylopius coccus Costa, is the colouring principle and is present in the final additive at 50%. The additive does not pose a risk concerning genotoxicity and is considered safe for dogs and cats at 264 and 220 mg Carmine/kg feed, respectively (which correspond to 132 and 110 mg carminic acid/kg feed, respectively). Due to the nature of the additive, the FEEDAP Panel concluded that allergic reactions may occur in the target species following the ingestion of feeds containing the additive. The FEEDAP Panel concluded that the exposure of users by inhalation is very likely, and that carmine is a respiratory and skin sensitiser; however, due to the lack of data, a conclusion cannot be reached on the potential skin and eye irritation of the additive. The additive is considered to be efficacious in feeds for dogs and cats under the proposed conditions of use.

Sterile thermoresponsive formulations for emergency management of burns

Initial care and treatment of burn injuries significantly influence their healing and appearance. The apt treatment for a burn patient normally depends upon the severity of the burn. This study was intended for the development of thermo-responsive formulations for the emergency management of burns prior to hospitalization.Nano calcium sulfate was prepared by probe sonication and nano copper oxide by thermal decomposition method and subsequently evaluated for particle size and poly-dispersity index. Formulations were prepared with 100 ppm of nano calcium sulphate, nano copper oxide and thermoresponsive polymers such as Poloxamer-407/ Chitosan/chitosan + Sodium β -glycerophosphate in different ratios. The products were evaluated for pH, viscosity and gelation time and those formulations which exhibited optimum viscosity, pH and gelation time were sterilized and evaluated for elemental content, skin irritation potential and in vivo burn healing activity.Nano calcium sulfate and nano copper oxide exhibited an average particle size of 220 nm and 273 nm correspondingly. SEM-EDX of selected formulations showed intense peaks of calcium and copper in all formulations. Acute dermal irritation study carried out on rabbits showed that the formations were non-irritant in nature. The percentage of wound contraction was greater in burn wounds treated with the formulation containing poloxamer-407 when compared to commercial Silverex™ ionic gel and the control group. The healing actvity of the thermoresponsive formulations was supported by histopathological studies.Nano calcium sulfate and nano copper oxide incorporated thermo-responsive formulations with burn wound healing activity were developed successfully.

Dermal Safety of Tapinarof Cream 1%: Results From 4 Phase 1 Trials

Tapinarof (VTAMA®; Dermavant Sciences, Inc.) is a novel, non-steroidal, topical, aryl hydrocarbon receptor agonist, FDA approved for psoriasis treatment and under investigation for atopic dermatitis treatment as a 1% cream formulation for once-daily (QD) application. Evaluate cumulative skin irritation, sensitization, and photoallergic and phototoxic potential of tapinarof cream 1% across a range of dosing frequencies and conditions. We conducted 4 randomized, controlled, phase 1 trials of topical tapinarof cream 1% vs vehicle or other appropriate controls in healthy adults. Cumulative skin irritation was assessed following QD application for 21 days under fully occlusive patch conditions. Contact sensitization, photoallergenicity, and phototoxicity were assessed under semi-occlusive patch conditions. The contact sensitization and photoallergenicity trials used an induction phase of repeated applications followed by a 2-week rest period and a 1-time challenge, with rechallenge if responses indicated sensitization/photosensitization; the phototoxicity trial comprised a single application. Ultraviolet A and B irradiation was used to assess photoallergenicity/toxicity. 376 participants were randomized across the 4 trials. In the cumulative irritation trial, tapinarof cream 1% QD was classified as having a slight potential for very mild cumulative irritation under the exaggerated test conditions of repeated dosing for 21 days. There was no evidence of sensitization, photosensitization, or phototoxicity. Tapinarof was well tolerated and there was a low discontinuation rate across all trials. Tapinarof cream 1% was well tolerated, non-sensitizing, non-phototoxic, and non-photoallergic, with no evidence of clinically meaningful cumulative skin irritation in 4 dermal safety trials in healthy adults. IND 104601 J Drugs Dermatol. 2022;21(10):1084-1090. doi:10.36849/JDD.6627R1.

31037 Assessment of actives and formula on antipigmentation efficacy

Hyperpigmentation is a skin condition resulting from overproduction of melanin, the pigment produced by melanocytes. Melanocytes reside at the basal layer of the epidermis, producing melanin and transferring it to surrounding keratinocytes to protect the skin from UV damage. As we get older, irregularities develop, such as dark spots and uneven skin tone. Simple topical treatments against melanin overproduction are not always effective, due to skin irritability of potent ingredients or lack of penetration into the skin. A two-step approach was designed to screen for efficacious antipigmentation actives and validate performance in a finished formulation. First, potentially effective ingredients were screened for cytotoxicity and melanin synthesis inhibition using darkly pigmented normal human melanocytes. One of the efficacious ingredients identified without causing melanocyte cytotoxicity is bisabolol. Next, bisabolol is formulated into formulas with additional beneficial ingredients, and assessed on a 3D skin model for antipigmentation efficacy as well as skin irritability. MelanoDerm model was used to evaluate two different finished formulations that include bisabolol. MelanoDerm was treated with 2 final formulas as well as 2 placebo control formulas, which lacked bisabolol. The positive control was 2% kojic acid. The efficacy was assessed after 2 weeks of treatments. Compared with placebo controls, formula with bisabolol inhibited melanin synthesis. Additionally, collected media was used to evaluate skin irritation potential by assessing IL-1a release by ELISA. Final formulas had minimal impact on IL-1a release. Utilizing both monolayer melanocytes and MelanoDerm, efficacious anti-pigmentation products were validated without concerns on skin irritation.

32661 Clinical evaluation of deodorant efficacy and tolerance for overall body odor control

Sweating and associated odor negatively impact self-confidence and social acceptance as they are linked to poor hygiene. Rapid multiplication of bacteria and sweat breakdown causes malodor. High “sweaters” e.g. with hyperhidrosis, are more susceptible to developing body odor. While deodorants for the axilla are used to contain odor, there is need for products to help eliminate other body part odors as well. A randomized, blinded clinical study in healthy volunteers (F, 18-67y) testing involving 3 body odor control products with completion of 90 volunteers (30 per arm). Clinical design involved 1 randomized underarm designated as the treatment site, receiving 1 of 3 test products with the other underarm remaining untreated. Four expert graders conducted underarm visual and malodor assessments at 8, 12, 24, 48, and 72 hrs after final product application. Efficacy of the product on vaginal/perineal/anal malodor was determined at 8 hours after application. The results of the comparative malodor analysis indicated significant differences between products at all assessment intervals favouring PCR Code A as statistically more effective in controlling malodor at all timepoints. Posttreatment malodor scores with PCR Code A use on their private parts indicated a significant reduction in malodor from baseline, 8 hours postapplication. Subject perception showed highly favourable results for product attributes of feel, texture, no residue, odor reduction, skin tolerance, and dual purpose. In conclusion, the dual-purpose deodorant with its clinically proven performance in terms of feel, odor control and low skin irritation potential is effective in controlling arm pit and vaginal/perineal/anal odor.

In vitro and in vivo antimicrobial activity of an active plant-based quadrocomplex for skin hygiene

Context: The current epidemiological situation causes a new surge of interest to perspective antimicrobial formulations for proper skin hygiene. Aims: To evaluate in vitro and in vivo the antimicrobial activity of a novel active quadrocomplex (QC) for skin hygiene based on Melaleuca alternifolia essential oil, eucalyptol, (-)-α-bisabolol and silver citrate. In addition, to analyze the phytochemical constituents by gas chromatography-mass spectrometry (GC-MS) and to assess the skin irritant potential after regular washing. Methods: The phytochemical analysis was performed using GC-MS. The Minimum Inhibitory Concentrations (MICs) were assessed using a colony-counting method with resazurin. The type of pharmacological interaction was investigated using a modern checkerboard assay. Results: The chemical composition exhibited 18 resolved phytochemicals with the highest concentrations for (-)-α-bisabolol (32.2%) and terpinen-4-ol (31.6%) through the GC-MS analysis. QC agents showed antimicrobial activity against Gram-positive and Gram-negative strains, with MIC values ranging from 1.25 to 40.00 mg/mL. The checkerboard assay demonstrated reduced MIC values for the combinations of QC agents against all reference strains. QC showed significant inhibition of Staphylococcus aureus growth with an average efficiency of 99.91% and Candida albicans 99.94 %. In vivo, the investigation of QC showed higher immediate and prolonged efficiency compared to base formulation (p<0.05). Dermatology evaluation indicated that QC added to the soap base did not affect the skin of hands during regular hand-washing and did not cause any negative effects on the skin. Conclusions: QC exhibits a balanced performance between antimicrobial activity and biological safety and can be considered a promising bioactive composition for regular hand hygiene application. Therefore, additional investigations are needed to study the mechanism of antimicrobial activity.