POTASSIUM SORBATE

Ocular surface disease (OSD) is a complex condition that can cause a range of symptoms (e.g, dryness, irritation, and pain) and can significantly impact the quality of life of affected individuals. Iatrogenic OSD, a common finding in patients with glaucoma who receive chronic therapy with topical ocular antihypertensive drugs containing preservatives such as benzalkonium chloride (BAK), has been linked to damage to the ocular surface barrier, corneal epithelial cells, nerves, conjunctival goblet cells, and trabecular meshwork. Chronic BAK exposure activates inflammatory pathways and worsens symptoms, compromising the success of subsequent filtration surgery in an exposure-dependent manner. In eyes being treated for glaucoma, symptomatic treatment of OSD may provide some relief, but addressing the root cause of the OSD often necessitates reducing or, ideally, eliminating BAK toxicity. Strategies to decrease BAK exposure in patients with glaucoma encompass the use of preservative-free formulations or drugs with alternative and less toxic preservatives such as SofZia®, Polyquad, potassium sorbate, or Purite®. Though the benefits of these alternative preservatives are largely unproven, they might be considered when financial constraints prevent the use of preservative-free versions. For patients receiving multiple topical preserved drugs, the best practice is to switch to nonpreserved equivalents wherever feasible, regardless of OSD severity. Furthermore, nonpharmacological approaches, including laser or incisional procedures, should be considered. This review explores the effects of BAK on the ocular surface and reviews strategies for minimizing or eliminating BAK exposure in patients with glaucoma in order to significantly improve their quality of life and prevent complications associated with chronic exposure to BAK.

Preservatives are used to stabilize topical preparations and protect the user from the influence of pathogenic microbes. After the application of a topical preparation, the matrix undergoes a metamorphosis, and by proportional evaporation of the hydrophilic phase the preservative may accumulate on the skin surface. This is believed to lead to antiseptic effects and may influence the diversity of the cutaneous microbiota. The regulation of the cutaneous microbiome and the associated influencing factors is a complex system that results in highly individualized conditions. Therefore, investigations on the influence of defined interventions are methodologically difficult. In the present proof-of-concept study, potential antiseptic effects of preservatives were investigated in a combination of in vitro and in vivo methods using microbiological culture tests. In addition, the investigations served to develop a clinical study design to answer further questions and use of an extended range of methods. The results support the hypothesis of an antiseptic effect of the tested preservatives (methyl-4-hydroxybenzoate and propyl-4-hydroxybenzoate, potassium sorbate and propylene glycol) on prominent reference bacteria, which could also be observed in clinical settings. Konservierungsmittel dienen der Haltbarmachung topischer Präparate und schützen dadurch den Anwender vor dem Einfluss pathogener Mikroben. Mit der Applikation des Topikums durchläuft die Matrix eine Metamorphose, in deren Folge es, durch anteilige Volatilisierung der hydrophilen Phase, zur Anreicherung des Konservierungsmittels auf der Hautoberfläche kommen kann. Es wird angenommen, dass dies zu antiseptischen Effekten und der Beeinflussung der Diversität der kutanen Mikrobiota führt. Wegen der Komplexität der Regulation des kutanen Mikrobioms und der damit verbundenen Einflussfaktoren resultiert ein hoher Grad der Individualisierung, sodass Untersuchungen zum Einfluss von definierten Interventionen methodisch schwierig sind. In der vorliegenden „Proof-of-concept“-Studie wurden mögliche antiseptische Effekte von Konservierungsmitteln in einer Kombination von In-vitro- und In-vivo-Methoden mittels mikrobiologischer Kulturversuche untersucht. Darüber hinaus dienten die Untersuchungen der Erarbeitung eines klinischen Studiendesigns für weiterführende Fragestellungen und erweitertem Methodenspektrum.Die Ergebnisse stützen die Hypothese einer antiseptischen Wirkung der getesteten Konservierungsmittel (Methyl-4-hydroxybenzoat und Propyl-4-hydroxybenzoat, Sorbinsäure/Kaliumsorbat und Propylenglykol) auf prominente Referenzbakterien und konnten auch im klinischen Setting beobachtet werden.

The cosmetic industry needs new preservatives that are effective, natural, safe, cost effective, sustainable and compliant with regulatory standards. This necessity has posed challenges requiring obligations, bioinformatics and bioinspiration as driving forces. Twenty natural extracts were selected from the Greenpharma Database with parameter filters corresponding to development constraints and antimicrobial properties. We confirmed using minimum inhibition concentration (MIC) assays that eight of the extracts have good bactericidal properties and that one has a high antifungal activity. The latter was purified hinokitiol, a bioproduct from Aomori Hiba wood. This substance provides high resistance against putrefaction; for instance, old Japanese temples were made of Aomori Hiba wood. The combination of hinokitiol with levulinic acid, another bioproduct, demonstrated complementary antimicrobial activities and synergistic effects in MIC studies and measurements according to Kull synergy index. Further, the mixture Hinoline® was tested at 2% in challenge tests and fulfilled criteria A of different standards. It also exerted complementary preservative effects with potassium sorbate and beneficial effects in unbalanced skin microbiota. Hinoline, a new effective preservative from renewable bioresources, was developed. This study accelerates the development of a preservative solution for cosmetics selected from Greenpharma Database, through bioinspiration and the identification of cost-effective investments and resources.

The preservatives sorbic acid (SA) and potassium sorbate (PS) are considered rare skin sensitizers. PS-containing products always contain SA to a certain extent, and positivity to PS may reflect sensitization to SA. Their optimal patch-test conditions are unknown. To report on the outcome of testing with SA and PS in various concentrations and/or vehicles. Seventeen patients with allergic contact dermatitis from PS/SA-containing topical pharmaceuticals and medical devices were patch tested to SA 2% and 5% pet.; SA 1%, 2%, 3%, 5%. eth.; and/or SA 2% aq., whereas PS was patch tested 5% pet. and/or 5% aq. Only one patient, not tested to the ethanol preparations, presented with a (doubtful) positive reaction to SA 2% pet., while this remained negative in 13 patients who reacted to SA 2% eth. The preparations containing SA 5% pet.; 1%, 3%, and 5% eth.; and SA 2% aq. had little or no additional value. PS 5% pet. performed better than 5% aq., and always mirrored SA sensitization. Sensitization to SA and PS is probably underestimated. SA 2% eth. and PS 5% pet. are preferred for patch testing, and patients sensitized to SA should avoid PS-containing products. Potassium sorbate (PS) and sorbic acid (SA) are widely used preservatives. PS-containing products always contain some SA. Both are considered rare skin sensitizers, but contact allergy in response to them might be underestimated. SA 2% eth. and PS 5% pet., rather than SA 2% pet. and PS 5% aq., respectively, may be required to diagnose contact allergy from PS/SA-containing topical pharmaceuticals and medical devices. A positive patch test to PS reflects sensitization to SA, and patients sensitized to SA should also avoid PS-containing products.

The safety assessment of cosmetic products is based on the safety of the ingredients, which requires information on chemical structures, toxicological profiles, and exposure data. Approximately 6% of the population is sensitized to cosmetic ingredients, especially preservatives and fragrances. In this context, the aim of this study was to perform a hazard assessment and risk characterization of benzalkonium chloride (BAC), benzyl alcohol (BA), caprylyl glycol (CG), ethylhexylglycerin (EG), chlorphenesin (CP), dehydroacetic acid (DHA), sodium dehydroacetate (SDH), iodopropynyl butylcarbamate (IPBC), methylchloroisothiazolinone and methylisothiazolinone (MCI/MIT), methylisothiazolinone (MIT), phenoxyethanol (PE), potassium sorbate (PS), and sodium benzoate (SB). Considering the integrated approaches to testing and assessment (IATA) and weight of evidence (WoE) as a decision tree, based on published safety reports. The hazard assessment was composed of a toxicological matrix correlating the toxicity level, defined as low (L), moderate (M), or high (H) and local or systemic exposure, considering the endpoints of skin sensitization, skin irritation, eye irritation, phototoxicity, acute oral toxicity, carcinogenicity, mutagenicity/genotoxicity, and endocrine activity. In a risk assessment approach, most preservatives had a margin of safety (MoS) above 100, except for DHA, SDH, and EG, considering the worst-case scenario (100% dermal absorption). However, isolated data do not set up a safety assessment. It is necessary to carry out a rational risk characterization considering hazard and exposure assessment to estimate the level of risk of an adverse health outcome, based on the concentration in a product, frequency of use, type of product, route of exposure, body surface location, and target population.

Potassium sorbate (PS) is a widely used antimicrobial additive employed as a preservative in food, cosmetics, and animal feed. Early childhood represents a critical developmental window characterized by rapid growth, immune system maturation, gut microbiota establishment, and physiological homeostasis development, which may be particularly vulnerable to chemical exposures (during which chemical exposures may exert heightened impacts). Nevertheless, the effects of PS on childhood development and gut microbiota remain poorly understood, and its potential trans-generational effects have yet to be elucidated. In this study, we employed Drosophila melanogaster , an established model for studying evolutionarily conserved aspects of development, metabolism, and host-microbiota interactions, to systematically evaluate PS toxicity across multiple parameters: developmental dynamics, gut microbiota composition, gene regulation in adulthood, and trans-generational effects. Our findings demonstrate a dose-dependent biphasic response: while low-dose PS exposure (25 mg/L) accelerated larval pupation and adult emergence, suggesting a potential growth-promoting effect, high-dose exposure (≥ 500 mg/L) significantly delayed development and reduced adult lifespan (observed in females at 1,000 and males at 500-1,000 mg/L). Notably, trans-generational analysis revealed persistent developmental delays in the F1 generation, with offspring of 1,000 mg/L-exposed parents showing prolonged larval pupation time despite normal adult emergence timelines, indicative of partial developmental recovery. Mechanistically, high-dose PS disrupted endocrine signaling and altered expression of key developmental pathway regulators ( EcR , InR , TOR , and E74B ). These transcriptional changes were largely reversible in offspring, further supporting a similar gradually wash out recovery. While gut microbiota remained stable in exposed parents, offspring of 1,000 mg/L-exposed flies had significant microbiome alterations, highlighting clear trans-generational dysbiosis. This study provides new evidence that PS exposure during a sensitive developmental period in D. melanogaster can perturb development and gut microbial homeostasis across generations, offering insights relevant to understanding how early-life chemical exposures might influence conserved biological processes in higher organisms.

Lemons are widely recognized for their culinary and nutritional value, but their high moisture content and delicate skin make them prone to postharvest quality loss and reduced antioxidant properties. This work explores the application of chitosan (CH) coatings enriched with potassium sorbate (PS) to preserve the quality and antioxidant system of lemons. The prepared coatings were characterized using Fourier transform infrared (FTIR) spectroscopy and rheology. FTIR spectra confirmed the successful incorporation of sorbate into the chitosan matrix, indicating the potential for antimicrobial activity. Rheological measurements revealed the viscoelastic properties of the coatings, essential for their applicability as protective layers on fruits. The results demonstrated that the composite coating significantly enhanced the activity of enzymes catalase, peroxidase and superoxide dismutase by the end of storage. Additionally, the composite-treated lemons exhibited better retention of total soluble solids (7.01%), acidity (5.14%), ascorbic acid (457 mg L -1 ) and antioxidant activity (34.56%) by the end of storage, indicating improved nutritional stability. The CH 2.0% + PS 1.0% smeared fruits showed reduced weight loss and decay rate. The results suggest that application of CH and PS composite coatings could serve as an efficient method for maintaining the postharvest quality of lemon fruits stored for 60 days at 90-95% relative humidity and 6-8 °C. © 2025 Society of Chemical Industry.

Potassium sorbate (PS) is a preservative widely used in the food, pharmaceutical, and cosmetics industries. Improper and careless use of PS can lead to various health issues and potential environmental problems. Drosophila is capable of making rapid and sensitive responses to stress or other stimuli. Here we utilized Drosophila as a model organism to evaluate the potential toxicity of PS. Our study revealed that PS ingestion reduced the lifespan and fecundity of Drosophila . In addition, excessive PS ingestion led to cell apoptosis and ROS accumulation in the midgut. Furthermore, PS intake also enhanced the mitophagy of midgut cells. Strikingly, PS affected the cell differentiation progression as well, leading to the production of more enteroendocrine (EE) cells. We further demonstrated that the expression of notch (N), a vital player in intestinal stem cell (ISC) differentiation, was down-regulated in the midgut. This indicates that the differentiation progression was affected potentially by repressing the N expression.

Saponins are amphiphilic glycosidic secondary metabolites produced by numerous plants. So far only few of them have been thoroughly analyzed and even less have found industrial applications as biosurfactants. In this contribution we screen 45 plants from different families, reported to be rich in saponins, for their surface activity and foaming properties. For this purpose, the room-temperature aqueous extracts (macerates) from the alleged saponin-rich plant organs were prepared and spray-dried under the same conditions, in presence of sodium benzoate and potassium sorbate as preservatives and drying aids. For 15 selected plants, the extraction was also performed using hot water (decoction for 15 min) but high temperature in most cases deteriorated surface activity of the extracts. To our knowledge, for most of the extracts this is the first quantitative report on their surface activity. Among the tested plants, only 3 showed the ability to reduce surface tension of their solutions by more than 20 mN/m at 1% dry extract mass content. The adsorption layers forming spontaneously on the surface of these extracts showed a broad range of surface dilational rheology responses - from null to very high, with surface dilational elasticity modulus, E' in excess of 100 mN/m for 5 plants. In all cases the surface dilational response was dominated by the elastic contribution, typical for saponins and other biosurfactants. Almost all extracts showed the ability to froth, but only 32 could sustain the foam for more than 1 min (for 11 extracts the foams were stable during at least 10 min). In general, the ability to lower surface tension and to produce adsorbed layers with high surface elasticity did not correlate well with the ability to form and sustain the foam. Based on the overall characteristics, Saponaria officinalis L. (soapwort), Avena sativa L. (oat), Aesculus hippocastanum L. (horse chestnut), Chenopodium quinoa Willd. (quinoa), Vaccaria hispanica (Mill.) Rauschert (cowherb) and Glycine max (L.) Merr. (soybean) are proposed as the best potential sources of saponins for surfactant applications in natural cosmetic and household products.

Postharvest technologies, such as the application of coatings, could contribute to the extension of the shelf life of avocado fruit. The objective of the present research was to evaluate the effects of coating, based on agro-industrial co-products (citrus pectin, broken rice grain flour, and cellulosic rice skin nanofiber), sorbitol and potassium sorbate, on the quality of avocado (cultivar 'Quintal') stored under refrigeration. The coating contributed to a longer conservation of the green color of avocado, both peel and pulp, and significantly reducing the respiration rate of the coated fruit, which was 35% lower than that of the control fruit. The coated fruit was firmer and, possibly, the addition of cellulosic nanofiber contributed to the maintenance of this firmness. Regarding the bioactive compounds, there was no difference ( p  > 0.05) among the coated and control fruit. During refrigerated storage, total phenolic compounds content increased ( p  < 0.05) from 311.44 ± 25.89 to 800.25 ± 160.74 mg kg -1 gallic acid equivalents (GAE) in the control fruit, and from 242.86 ± 52.33 to 584.75 ± 125.57 mg kg -1 GAE in the coated fruit. It was concluded that the shelf life of avocado (cultivar 'Quintal') could be extended and ripening delayed by a minimum of 8 days, by applying a coating formulated with rice flour, pectin, sorbitol, potassium sorbate, and cellulosic rice skin nanofiber.

Cosmetic products contain a wide range of chemicals to which we are exposed every day. The aim of the study was to determine the presence of potential dangerous substances which can cause adverse health effects by examining product labels. A total of 283 products were collected from various shops in Lecce (Italy) and divided into 3 categories: rinse-off, leave-on and make-up. The label of every product was examined and a list including fragrances, preservatives and other chemicals of concern was created. Fragrances were present in 52.3% of the examined products, mostly limonene (76.9%) and linalool (64.6%) but also citronellol (34.1%), geraniol (31.5%), coumarin (30%) and hexyl cinnamal (29.2%). Preservatives showed a rate of 60% and the most frequently identified were phenoxyethanol (48.7%), sodium benzoate (35.6%), potassium sorbate (22%), methylparaben (15.2%) and MI/MCI (9.9%). The other chemicals of concern were detected in 58% of products; included PEGs (62.3%), acrylate copolymer (34%), petrolatum (17.2%), polysorbates (14,8%), BHT (14.7%), ethylhextyl methoxycinnamate (13.6%), benzophenone-1 (3.7%), benzophenone-3 (4.9%), BHA (1.6%), cocamide DEA and toluene (1.2%). The use of many of these substances is allowed within certain limits, due to their toxicity at higher concentrations. Other important aspects should be considered as, for instance, the possibility of long-term effects. On the other hand, other substances may induce several acute adverse side-effects, i.e. contact dermatitis and allergic reactions. For these reasons, an enhancement of the criteria used for cosmetics formulation is required since many chemicals used singularly or combined are potentially unsafe.