Toxicological properties and risk assessment of the anionic surfactants category: Alkyl sulfates, primary alkane sulfonates, and α-olefin sulfonates

Rationalizing Counterion Selection for the Development of Lipophilic Salts: A Case Study with Venetoclax

The use of lipid-based formulations (LBFs) can be hindered by low dose loading due to solubility limitations of candidate drugs in lipid vehicles. Formation of lipophilic salts through pairing these drugs with a lipophilic counterion has been demonstrated as a potential means to enhance dose loading in LBFs. This study investigated the screening of appropriate counterions to form lipophilic salts of the BCS class IV drug venetoclax. The physical properties, lipid solubility, and in vitro performance of the salts were analyzed. This study illustrated the versatility of alkyl sulfates and sulfonates as suitable counterions in lipophilic salt synthesis with up to ∼9-fold higher solubility in medium- and long-chain LBFs when compared to that of the free base form of venetoclax. All salts formulated as LBFs displayed superior in vitro performance when compared to the free base form of the drug due to the higher initial drug loadings in LBFs and increased affinity for colloidal species. Further, in vitro studies confirmed that venetoclax lipophilic salt forms using alkyl chain counterions demonstrated comparable in vitro performance to venetoclax docusate, thus reducing the potential for laxative effects related to docusate administration. High levels of the initial dose loading of venetoclax lipophilic salts were retained in a molecularly dispersed state during dispersion and digestion of the formulation, while also demonstrating increased levels of saturation in biorelevant media. The findings of this study suggest that alkyl chain sulfates and sulfonates can act as a suitable alternative counterion to docusate, facilitating the selection of counterions that can unlock the potential to formulate venetoclax as an LBF.

Biological responses in Danio rerio by the disinfectant SDBS in SARS-CoV-2 pandemic

The use of disinfectants, such as Sodium Dodecylbenzene Sulfonic acid salt (SDBS), has grown since the SARS-CoV-2 pandemic, with environmentally unknown consequences. The present study analyzed SDBS effects in the fish species Danio rerio, using a combination of biomarkers. Our data reported that larvae had their total locomotor activity increased when exposed to 1 mg/L of SDBS, but this parameter was decreased in fish exposed to 5 mg/L. A significant increment of erratic movements was reported in fish exposed to 1 and 5 mg/L of SDBS. These concentrations inhibited CYP1A1/CYP1A2, and of GSTs inhibition, suggesting SDBS is not preferentially biotransformed by these routes. Results concerning the antioxidant defense biomarkers (CAT and GPx) showed no straightforward pattern, suggesting SDBS exposure may have resulted in changes in redox balance. Finally, acetylcholinesterase activity increased. In summary, increased use of SDBS in a near future may result in deleterious effects in environmentally exposed fish.

Green Surfactants (Biosurfactants): A Petroleum-Free Substitute for Sustainability-Comparison, Applications, Market, and Future Prospects

Surfactants are a group of amphiphilic molecules (i.e., having both hydrophobic and hydrophilic domains) that are a vital part of nearly every contemporary industrial process such as in agriculture, medicine, personal care, food, and petroleum. In general surfactants can be derived from (i) petroleum-based sources or (ii) microbial/plant origins. Petroleum-based surfactants are obvious results from petroleum products, which lead to petroleum pollution and thus pose severe problems to the environment leading to various ecological damages. Thus, newer techniques have been suggested for deriving surfactant molecules and maintaining environmental sustainability. Biosurfactants are surfactants of microbial or plant origins and offer much added advantages such as high biodegradability, lesser toxicity, ease of raw material availability, and easy applicability. Thus, they are also termed "green surfactants". In this regard, this review focused on the advantages of biosurfactants over the synthetic surfactants produced from petroleum-based products along with their potential applications in different industries. We also provided their market aspects and future directions that can be considered with selections of biosurfactants. This would open up new avenues for surfactant research by overcoming the existing bottlenecks in this field.

Influence of the Linear Alkylbenzene Sulfonate (LAS) on hematological and biochemical parameters of Nile Tilapia, Oreochromis niloticus

The acute toxicity of household detergent (Ariel) on blood parameters and histology of Oreochromis niloticus was investigated using static bioassay for 96 h. Linear alkylbenzenesulfonate (LAS) is an anionic surfactant widely used in detergents and cleaners, both in industrial and household applications. LAS contaminating aquatic ecosystems as a potential toxic pollutant, was investigated in the present study for acute toxicity. The fish samples were divided into six groups, including 20 fish in each group. Normal feed was given to control group without detergents treatment. Hematological parameters (RBC count, Hb, Ht and platelets) were significantly declined, while WBC count showed a highly significant increase. Compared with the control group, significant elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was recorded in fish treated with different concentrations of detergent. Catalase (CAT), Superoxide dismutase (SOD) activities and Reduced Glutathione (GSH) concentration showed a highly significant reduction. Total proteins showed significant decrease, while total lipids, cholesterol and triglycerides significantly increased. The mean lethal concentration (LC₅₀) for 96 h of Ariel was at concentration 10 mg/L. Relative percentage of detergent residues in fish muscles was increased with higher detergent concentrations. In conclusion, exposure to detergents resulted in great alterations in the histological structure of liver and gills.

Relationship between sensorial and physical characteristics of topical creams: A comparative study on effects of excipients

Rising consumer demands for safer, more natural, and sustainable topical products have led to increased interest in finding alternative excipients, while retaining functionality and cosmetic appeal. Particle-stabilized Pickering creams have emerged as possible alternatives to replace traditional surfactant-stabilized creams and are thus one of the focuses in this study. The aim of this paper was to study relationships between sensorial characteristics and physical properties to understand how different excipients affect these aspects, comparing one starch particle-stabilized and three surfactant-stabilized formulations. A human panel was used to evaluate sensorial perception, while physical properties were deduced by rheology and tactile friction, together with in vivo and ex vivo skin hydration measurements. The results show that sensorial attributes related to the application phase can be predicted with rheology, while afterfeel attributes can be predicted with tactile friction studies. Differences in rheological and sensory properties among surfactant-based creams could mainly be attributed to the type of emollients used, presence of thickeners and surfactant composition. Differences between surfactant-based creams and a Pickering cream were more evident in relation to the afterfeel perception. Presence of starch particles in the residual film on skin results in high tactile friction and low perception of residual coating, stickiness, greasiness, and slipperiness in sensorial afterfeel.

High-performance sulphate-free cleansers: Surface activity, foaming and rheology

OBJECTIVE

The main objective of this paper is to analyse the composition of a sulphate-free binary or ternary surfactant system with alkyl olefin sulfonate (AOS), alkyl polyglucoside (APG) and lauryl hydroxysultaine (Sultaine). The composition was optimized by observing critical parameters such as surface activity and rheological properties while varying the concentration of APG in a ternary system, varying the ratio of AOS and Sultaine in a binary system and studying the effect of sodium chloride addition. The experimental results can provide an alternative, sulphate-free surfactant system to replace the common system containing sodium laureth sulfate (SLES) and cocamidopropyl betaine (CapB), without compromising on the parameters previously mentioned.

METHODS

A DuNouy Ring was utilized on a tensiometer to measure the surface tension of the samples. To observe foaming abilities of samples, a visual foaming study was conducted and recorded by taking pictures. A TA instruments mechanical rheometer was used to measure the viscosity.

RESULTS

Studying the effect of APG concentration on surface tension illustrated that as APG concentration decreases, surface tension decreases as well. The minimum surface tension was found to be 26.587 for 7.5 wt.% AOS and 7.5 wt.% Sultaine. When the ratio between AOS and Sultaine changed, the 1:1 system produced the lowest surface tension value again. As the concentration of AOS decreased in the ratio, the surface tension increased. When the ratio was held constant, and APG was introduced into the system, the systems containing APG had higher surface tension values compared with the systems with the same ratios but did not have APG added. As the concentration of salt increased, the surface tension decreased for AOS, increased for the binary mixture and had no effect on Sultaine. Foaming has a direct correlation with surface tension so a decrease in surface tension led to better foaming abilities; therefore, the 1:1 ratio of AOS:Sultaine had the best foaming qualities. The AOS/Sultaine system exhibited Maxwellian behaviour, suggesting the presence of worm-like micellar structures. As the concentration of APG increased, the viscosity decreased and at a concentration of 2.5 wt.% AOS, 5 wt.% APG and 7.5 wt.% Sultaine, the system changed from shear thinning non-Newtonian fluid to Newtonian. Varying the ratio of AOS:Sultaine in the binary system, showed as the ratio changed, the viscosity decreased, and at a ratio of 1:3 AOS:Sultaine, the system was primarily Newtonian. As the ratio remained constant and APG was added, the viscosity continued to decrease and the 1:3 ratio was completely Newtonian. The addition of salt had no effect on the viscosity of Sultaine, but the viscosity of AOS increased at a salt concentration of 2 wt.%. The binary mixture saw as the concentration of salt increased, the viscosity profile decreased, even though the system remained non-Newtonian and shear thinning.

CONCLUSION

The surface activity and rheological study of the sulfate-free surfactant systems unveil a strong synergistic interaction between AOS and Sultaine specifically at a ratio of 1:1 resulting in high surface activity and corresponding good foaming and formation of entangled wormlike micelles resulting in excellent viscosity build in the system. If introducing a biobased surfactant into this system is desired without completely compromising the performance properties, the ternary surfactant system 4.5 wt.% AOS, 3 wt.% APG and 7.5 wt.% Sultaine should be considered optimal. Any further addition of APG or changing the ratio results in detrimental reductions of all performance controlling physio-chemical parameters.

Does the Anionic Surfactant Isopropylamine Dodecylbenzene Sulfonate Induce Hepatic Oxidative Stress and Impairment in Carassius auratus gibelio?

Isopropylamine dodecylbenzene sulfonate (IDS) is a new kind of anionic surfactant (ANS). To preliminarily evaluate the aquatic toxicity of IDS, this study took gibel carp (Carassius auratus gibelio) as the research object. The well-acclimatized fish were divided into six groups and exposed to 0 mg/L, 0.5 mg/L, 1.0 mg/L, 2.0 mg/L, 4.0 mg/L, or 8.0 mg/L of IDS for 7, 14, 21 or 28 days. Our results showed that the superoxide dismutase (SOD) activity and malondialdehyde (MDA) content of the liver were unaffected by IDS exposure, while glutathione peroxidase (GSH-Px) activity was significantly inhibited. Hepatic tissue exhibited pathological damage, characterized by nuclear migration and dissolution and cell boundary blurring. The results suggest that IDS does not cause oxidative stress in the liver, but cause hepatic histopathological damage. GSH-Px can be considered as a biomarker of IDS exposure in gibel carp.

Evaluation of surface active and antimicrobial properties of alkyl D-lyxosides and alkyl L-rhamnosides as green surfactants

The use of carbohydrates, as a part of surface-active compounds, has been studied due to their biodegradability and nontoxic profile. A series of alkyl glycosides containing d-lyxose and l-rhamnose with alkyl chains of 8-12 carbon atoms were investigated. The effects of structural variations on their physico-chemical and biological properties have been evaluated for a detailed understanding of their properties. Alkyl glycosides were tested on their toxicity against bacterial cells of the genus Pseudomonas (MTT assay), microbiological adhesion to hydrocarbons (MATH assay), cell surface hydrophobicity (Congo red assay), cell membrane permeability (crystal violet assay), and bacterial biofilm formation. Furthermore, their antifungal activity against two pathogenic microorganisms Candida albicans and Aspergillus niger was investigated using the disc diffusion method. Toxicological studies revealed that compounds could reduce the metabolic activity of bacterial cells only moderately but they increased the hydrophobicity of cell surface in Pseudomonas strains. In addition, alkyl glycosides changed the permeability of the cell membranes to the level of 30-40% for this strain. The compounds with an even number of carbon atoms in their alkyl chain promoted stronger bacterial biofilm formation on the glass surface. All studied derivatives demonstrated very strong antifungal activity against fungus A. niger but very small effect against C. albicans. Overall, the results showed that long-chain alkyl glycosides could be considered as inexpensive, biocompatible, nontoxic agents, and serve for the surface design to avoid bacterial adhesion as an alternative solution to antibiotic treatment.

Isolation and Characterization in a Soil Conditioned With Foaming Agents of a Bacterial Consortium Able to Degrade Sodium Lauryl Ether Sulfate

The anionic surfactant Sodium Lauryl Ether Sulfate (SLES) is the principal component of several commercial foaming products for soil conditioning in the tunneling industry. Huge amounts of spoil material are produced during the excavation process and the presence of SLES can affect its re-use as a by-product. Anionic surfactants can be a risk for ecosystems if occurring in the environment at toxic concentrations. SLES biodegradability is a key issue if the excavated soil is to be reused. The aim of this study was to identify bacteria able to degrade SLES, so that it could potentially be used in bioaugmentation techniques. Enrichment cultures were performed using bacterial populations from spoil material collected in a tunnel construction site as the inoculum. A bacterial consortium able to grow in a few hours with SLES concentrations from 125 mg/L to 2 g/L was selected and then identified by Next Generation Sequencing analysis. Most of bacteria identified belonged to Gamma-Proteobacteria (99%) and Pseudomonas (ca 90%) was the predominant genus. The bacterial consortium was able to degrade 94% of an initial SLES concentration of 250 mg/L in 9 h. A predictive functional analysis using the PICRUSt2 software showed the presence of esterase enzymes, responsible for SLES degradation. The bacterial consortium selected could be useful for its possible seeding (bioaugmentation) on spoil material from tunneling excavation.

Efavirenz nanomicelles loaded vaginal film (EZ film) for preexposure prophylaxis (PrEP) of HIV

Preexposure prophylaxis (PrEP) using oral or vaginal microbicide is an emerging and effective strategy to prevent HIV transmission. Vaginal film is becoming more acceptable and a convenient dosage form compared to cream, gel and suppository. Extremely poor aqueous solubility of efavirenz (EFV) limits its use as vaginal microbicide. The aim of this study was to develop and evaluate a monomeric surfactant free, rapidly soluble vaginal film of EFV (EZ film). EZ film was prepared using a tetrafunctional block polymer (Tetronic 1107), carrageenan and polyvinyl alcohol (PVA) by solvent evaporation method. First, different solubilizers were screened for EFV solubility, in vitro cytotoxicity and cell membrane integrity assay on HeLa cells. Optimized film was characterized for solid state, mechanical strength, epithelial integrity, in vitro drug release in simulated vaginal fluid (SVF), simulated seminal fluid (SSF) and in vitro anti-HIV activity. Optimized EZ film showed a particle size of 48 ± 3.8 nm with PDI of 0.299. Differential scanning colorimetry (DSC) thermogram suggested the complete amorphization of EFV within the film. EZ film rapidly disintegrated (30 s) with complete release of EFV in SVF and SSF. The film was found to be non-toxic to HeLa cells and showed similar anti-HIV-1 activity as that of EFV in DMSO. EZ film did not show any significant change in the TEER value in HEC 1A cell line. Hence, the findings from the current study strongly suggest that the EZ film could be a cost-effective and convenient dosage form for PrEP of HIV.

API ionic liquids: probing the effect of counterion structure on physical form and lipid solubility

Lipid based formulations (LBFs) are extensively utilised as an enabling technology in drug delivery. The use of ionic liquids (ILs) or lipophilic salts (LS) in drug delivery has also garnered considerable interest due to unique solubility properties. Conversion of active pharmaceutical ingredients (API) to ILs by pairing with an appropriately lipophilic counterion has been shown to decrease melting point of the salt complex and improve solubility in LBFs. However, the relationship between the structure of the counterion, the physicochemical properties of the resulting salts and solubility in LBFs has not been systematically explored. This study investigates the relationship between alkyl sulfate counterion structure and melting temperature (T m or T g) in addition to LBF solubility, utilizing cinnarizine and lumefantrine as model weakly basic APIs. Three series of structurally diverse alkyl sulfate counterions were chosen to probe this relationship. Pairing cinnarizine and lumefantrine with a majority of these alkyl sulfate counterions resulted in a reduction in melting temperature and enhanced solubility in model medium chain and long chain LBFs. The chain length of the alkyl sulfate plays a crucial role in performance, and consistently branched alkyl sulfate counterions perform better than straight chain alkyl sulfate counterions, as predicted. Most interestingly, trends in counterion performance were found to be consistent across two APIs with disparate chemical structures. The findings from this study will facilitate the design of counterions which enhance solubility of ionisable drugs and unlock the potential to develop compounds previously restrained by poor solubility.

Biological impact of octyl d-glucopyranoside based surfactants

Development of many branches of industry has stimulated the search for new, effective surfactants with interesting properties. Potential use of alkyl glucose derivatives on a large scale, raises questions about the possible risks associated with their entry into the natural environment. To be able to evaluate this risk, the aim of the study was to determine the physicochemical properties of octyl d-glucopyranoside and its three derivatives: N-(octyl d-glucopyranosiduronyl)aspartic acid, N-(octyl d-glucopyranosiduronyl)glicyne and octyl d-glucopyranosiduronic acid. Moreover, their biodegradability by pure bacterial strains and biocenosis present in river water was examined. While descriptions of sugar-based surfactants on microbial cells are limited, the essential element of the study was to determine the effect of surfactants on cell surface properties of microorganisms isolated from activated sludge and compare it to the effects of the petroleum based surfactants and the surfactants produced from renewable materials. The results obtained indicate that physicochemical properties of surface active agents differ depending on the presence of functional groups in the surfactants molecules. What is more, the presence of amino acid substituent in the derivatives of octyl d-glucopyranoside resulted in a slight decrease in the surfactants biodegradation efficiency, in comparison to the compounds that did not contain such a substituent, prolonging this process from 5 to 10 days. Interestingly, even relatively slightly different derivatives modified the cell surface properties in a different way. Importantly, the surfactants based on octyl d-glucopyranoside have less negative impact on environmental microorganism and better biodegradability than the surfactant synthesized from petroleum products.

A quantitative screening-level approach to incorporate chemical exposure and risk into alternative assessment evaluations

As the general public and retailers ask for disclosure of chemical ingredients in the marketplace, a number of hazard screening tools were developed to evaluate the so-called "greenness" of individual chemical ingredients and/or formulations. The majority of these tools focus only on hazard, often using chemical lists, ignoring the other part of the risk equation: exposure. Using a hazard-only focus can result in regrettable substitutions, changing 1 chemical ingredient for another that turns out to be more hazardous or shifts the toxicity burden to others. To minimize the incidents of regrettable substitutions, BizNGO describes "Common Principles" to frame a process for informed substitution. Two of these 6 principles are: "reduce hazard" and "minimize exposure." A number of frameworks have emerged to evaluate and assess alternatives. One framework developed by leading experts under the auspices of the US National Academy of Sciences recommended that hazard and exposure be specifically addressed in the same step when assessing candidate alternatives. For the alternative assessment community, this article serves as an informational resource for considering exposure in an alternatives assessment using elements of problem formulation; product identity, use, and composition; hazard analysis; exposure analysis; and risk characterization. These conceptual elements build on practices from government, academia, and industry and are exemplified through 2 hypothetical case studies demonstrating the questions asked and decisions faced in new product development. These 2 case studies-inhalation exposure to a generic paint product and environmental exposure to a shampoo rinsed down the drain-demonstrate the criteria, considerations, and methods required to combine exposure models addressing human health and environmental impacts to provide a screening level hazard and exposure (risk) analysis. This article informs practices for these elements within a comparative risk context to improve alternatives assessment evaluation and decision making. Integr Environ Assess Manag 2017;13:1007-1022. © 2017 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Characteristics and environmental fate of the anionic surfactant sodium lauryl ether sulphate (SLES) used as the main component in foaming agents for mechanized tunnelling

The anionic surfactant sodium lauryl ether sulphate (SLES) is the main component of most commercial products used for soil conditioning in the excavation industry, in particular as lubricants for mechanized tunnelling. Its use during the excavation processes can result in either the subsequent possible re-use of the huge amount of soil debris as by-products (e.g. land covering) or its discharge as waste. Currently, there are neither SLES soil threshold limits in European legislation, nor comprehensive studies on the environmental risk for soil ecosystems in these exposure scenarios. In this context, the present paper reviews the available data on the intrinsic characteristics of persistence and the ecotoxicological effects of the anionic surfactant SLES. Although SLES is generally reported to be biodegradable in standard tests, with degradation rates between 7 h and 30 days, depending on the initial conditions, data on its biodegradation in environmental studies are quite scarce. Consequently, assessing SLES biodegradation rates in field conditions is crucial for evaluating if in residual concentrations (typically in the range 40-500 mg/kg in excavated soils) it can or not be a potential hazard for terrestrial and water organisms. Laboratory ecotoxicological tests pointed out detrimental effects of SLES for aquatic organisms, while data on the terrestrial species are rather poor so far and further studies at the expected environmental concentrations are necessary. Finally, the review reports the main analytical methods available for detecting anionic surfactants in solid matrices and the future research needed to improve knowledge on the possible environmental risks posed by the use of SLES in foaming agents for mechanized tunnelling.

Quantifying the benefits of using read-across and in silico techniques to fulfill hazard data requirements for chemical categories

Substantial benefits are realized through the use of read-across and in silico techniques to fill data gaps for structurally similar substances. Considerable experience in applying these techniques was gained under two voluntary high production volume (HPV) chemical programs - the International Council of Chemical Associations' (ICCA) Cooperative Chemicals Assessment Programme (with the cooperation of the Organization of Economic Cooperation and Development) and the U.S. Environmental Protection Agency's HPV Challenge Program. These programs led to the compilation and public availability of baseline sets of health and environmental effects data for thousands of chemicals. The American Cleaning Institute's (ACI) contribution to these national and global efforts included the compilation of these datasets for 261 substances. Chemicals that have structural similarities are likely to have similar environmental fate, physical-chemical and toxicological properties, which was confirmed by examining available data from across the range of substances within categories of structurally similar HPV chemicals. These similarities allowed the utilization of read-across, trend analysis techniques and qualitative structure activity relationship ((Q)SAR) tools to fill data gaps. This paper presents the first quantification of actual benefits resulting from avoided testing through the use of read-across and in silico tools. Specifically, in the evaluation of these 261 noted substances, the use of 100,000-150,000 test animals and the expenditures of $50,000,000 to $70,000,000 (US) were avoided.

Alkylsulfuric acid ionic liquids: a promising class of strongly acidic room-temperature ionic liquids

Alkylsulfuric acid ILs are simple to make and offer a more strongly acidic alternative to sulfonic acid ILs for applications in catalysis, metal extraction and dissolution of metal oxides.