Comparative studies on the ocular and dermal irritation potential of surfactants

Antifungal Activity and Stability of Fluconazole Emulsion Containing Ionic Liquids Explained by Intermolecular Interactions

This research reports accelerated stability experiments, the evaluation of intermolecular interactions, and antifungal assays for fluconazole emulsions prepared using ultrasound (US) and magnetic stirring (MS) in the presence of ionic liquids derived from 1,n-(3-methylimidazolium-1-yl)alkane bromide ([CnMIM]Br; n = 12 or 16). The goals of the investigation are to quantify the stability, identify the forces that drive the formation and stability, and determine the antifungal activity of fluconazole-containing emulsions, and corroborate the data from our previous results that indicated that the emulsion based on [C16MIM]Br seemed to be more stable. In this study, accelerated stability experiments evidenced a considerable stability for the [C16MIM]Br emulsions at two temperatures (25 and 37 °C)—the instability index increased in the following order: US40% < US20% < MS. The 1H NMR data showed that the ILs interacts differently with medium-chain triglycerides (MCT). Two distinct interaction mechanisms were also observed for [C12MIM]Br and [C16MIM]Br with fluconazole, in which the latter formed more compact mixed aggregates than the former. The result was corroborated by diffusion data, which showed that ILs suffered a decrease in diffusion in the presence of fluconazole. The antifungal assay showed that emulsions containing ILs displayed superior activity compared with fluconazole alone. The emulsions also showed potent activity in inhibiting a resistant species (C. glabrata—CG34) to FLZ. All emulsions showed weak irritant potential in HET-CAM assay.

Análisis del rótulo y características de los jabones utilizados en la piel del recién nacido

Objetivo:

Analizar la información del rótulo, y las características físicas y fisicoquímicas de los jabones usados en recién nacidos (RN).

Método:

Estudio cuantitativo y descriptivo de 17 jabones comercializados en San Pablo, Brasil. Se analizó la información del rótulo (tensioactivos, pruebas de seguridad y descripción del valor de pH), y las características físicas (color y fragancia) y fisicoquímicas (valor de pH) del producto; las dos últimas, en laboratorio.

Resultados:

Se identificaron 27 tipos de tensioactivos: 70,3% (n=19) aniónicos, 18,5% (n=5) anfóteros y 11,1% (n=3) no iónicos. El 37% (n=10) tuvo un potencial moderado de irritación. En cuanto a las pruebas de seguridad, la mayoría de las formulaciones (94,1%) citó “dermatológicamente probado”. Sólo 42% citó “oftalmológicamente probado”. La translucidez estuvo presente en 23,5% (n=4) de los jabones. Todas las formulaciones presentaron fragancia. El promedio más alto de valor de pH fue de jabones en barra tradicionales (9,94 DE 0,81).

Conclusión:

Las formulaciones analizadas indicaron un potencial de irritación bajo o moderado. Cuatro jabones líquidos y uno en barra combinados tuvieron valores cercanos a los del pH de la piel del RN, y mostraron ser adecuados para la homeostasis de la barrera cutánea. Aunque las formulaciones citaron “dermatológicamente probado”, no todas citaron “oftalmológicamente probado”. Este estudio proporciona elementos para seleccionar un jabón adecuado para el RN.

Formulation and evaluation of butenafine loaded PLGA-nanoparticulate laden chitosan nano gel

The present research work is designed to prepare and optimize butenafine (BT) loaded poly lactic co glycolic acid (PLGA) nanoparticles (BT-NPs). BT-NPs were prepared by emulsification probe sonication method using PLGA (A), PVA (B) as polymer and stabilizer, respectively. The optimum composition of BT-NPs was selected based on the point prediction method given by the Box Behnken design software. The optimized composition of BT-NPop showed a particle size of 267.21 ± 3.54 nm with an entrapment efficiency of 72.43 ± 3.11%. The optimum composition of BT-NPop was further converted into gel formulation using chitosan as a natural polymer. The prepared topical gel formulation (BT-NPopG) was further evaluated for gel characterization, drug release, permeation study, irritation, and antifungal studies. The prepared BT-NPopG formulation showed optimum pH, viscosity, spreadability, and drug content. The release and permeation study results revealed slow BT release (42.76 ± 2.87%) with significantly enhanced permeation across the egg membrane. The irritation study data showed negligible irritation with a cumulative score of 0.33. The antifungal study results conclude higher activity than marketed as well as pure BT. The overall conclusion of the results revealed BT-NPopG as an ideal delivery system to treat topical fungal infection.

Formulation, Optimization and Evaluation of Luteolin-Loaded Topical Nanoparticulate Delivery System for the Skin Cancer

In the present study, luteolin (LT)-loaded nanosized vesicles (LT-NVs) were prepared by a solvent evaporation-hydration method using phospholipid and edge activator. The formulation was optimized using three factors at a three-level Box-Behnken design. The formulated LT-NVs were prepared using the three independent variables phospholipid (A), edge activator (B) and sonication time (C). The effect of used variables was assessed on the vesicle size (Y1) and encapsulation efficiency (Y2). The selection of optimum composition (LT-NVopt) was based on the point prediction method of the software. The prepared LT-NVopt showed the particle size of 189.92 ± 3.25 nm with an encapsulation efficiency of 92.43 ± 4.12% with PDI and zeta potential value of 0.32 and -21 mV, respectively. The formulation LT-NVopt was further converted into Carbopol 934 gel (1% w/v) to enhance skin retention. LT-NVoptG was further characterized for viscosity, spreadability, drug content, drug release, drug permeation and antioxidant, antimicrobial and cytotoxicity assessment. The evaluation result revealed optimum pH, viscosity, spreadability and good drug content. There was enhanced LT release (60.81 ± 2.87%), as well as LT permeation (128.21 ± 3.56 µg/cm2/h), which was found in comparison to the pure LT. The antioxidant and antimicrobial study results revealed significantly (p ˂ 0.05) better antioxidant potential and antimicrobial activity against the tested organisms. Finally, the samples were evaluated for cytotoxicity assessment using skin cancer cell line and results revealed a significant difference in the viability % at the tested concentration. LT-NVoptG showed a significantly lower IC50 value than the pure LT. From the study, it can be concluded that the prepared LT-NVoptG was found to be an alternative to the synthetic drug as well as conventional delivery systems.

An overview of current alternative models in the context of ocular surface toxicity

The 21st century has seen a steadily increasing social awareness of animal suffering, with increased attention to ethical considerations. Developing new integrated approaches to testing and assessment (IATA) strategies is an Organisation for Economic Co-operation and Development (OECD) goal to reduce animal testing. Currently, there is a lack of alternative models to test for ocular surface toxicity (aside from irritation) in lieu of the Draize eye irritation test (OECD guideline No. 405) performed in rabbits. Five alternative in vitro or ex vivo methods have been validated to replace this reference test, but only in combination. However, pathologies like Toxicity-Induced Dry Eye (TIDE), cataract, glaucoma, and neuropathic pain can occur after exposure to a pharmaceutical product or chemical and therefore need to be anticipated. To do so, new models of lacrimal glands, lens, and neurons innervating epithelia are required. These models must take into account real-life exposure (dose, time, and tear film clearance). The scientific community is working hard to develop new, robust, alternative, in silico, and in vitro models, while attempting to balance ethics and availability of biological materials. This review provides a broad overview of the validated methods for analyzing ocular irritation and those still used by some industries, as well as promising models that need to be optimized according to the OECD. Finally, we give an overview of recently developed innovative models, which could become new tools in the evaluation of ocular surface toxicity within the scope of IATAs.

Soapwort (Saponaria officinalis L.) Extract vs. Synthetic Surfactants-Effect on Skin-Mimetic Models

Our skin is continuously exposed to different amphiphilic substances capable of interaction with its lipids and proteins. We describe the effect of a saponin-rich soapwort extract and of four commonly employed synthetic surfactants: sodium lauryl sulfate (SLS), sodium laureth sulfate (SLES), ammonium lauryl sulfate (ALS), cocamidopropyl betaine (CAPB) on different human skin models. Two human skin cell lines were employed: normal keratinocytes (HaCaT) and human melanoma cells (A375). The liposomes consisting of a dipalmitoylphosphatidylcholine/cholesterol mixture in a molar ratio of 7:3, mimicking the cell membrane of keratinocytes and melanoma cells were employed as the second model. Using dynamic light scattering (DLS), the particle size distribution of liposomes was analyzed before and after contact with the tested (bio)surfactants. The results, supplemented by the protein solubilization tests (albumin denaturation test, zein test) and oil emulsification capacity (using olive oil and engine oil), showed that the soapwort extract affects the skin models to a clearly different extent than any of the tested synthetic surfactants. Its protein and lipid solubilizing potential are much smaller than for the three anionic surfactants (SLS, ALS, SLES). In terms of protein solubilization potential, the soapwort extract is comparable to CAPB, which, however, is much harsher to lipids.

Microfluidic production of monodisperse emulsions for cosmetics

Droplet-based microfluidic technology has enabled the production of emulsions with high monodispersity in sizes ranging from a few to hundreds of micrometers. Taking advantage of this technology, attempts to generate monodisperse emulsion drops with high drug loading capacity, ordered interfacial structure, and multi-functionality have been made in the cosmetics industry. In this article, we introduce the practicality of the droplet-based microfluidic approach to the cosmetic industry in terms of innovation in productivity and marketability. Furthermore, we summarize some recent advances in the production of emulsion drops with enhanced mechanical interfacial stability. Finally, we discuss the future prospects of microfluidic technology in accordance with consumers' needs and industrial attributes.

Formulation and Optimization of Butenafine-Loaded Topical Nano Lipid Carrier-Based Gel: Characterization, Irritation Study, and Anti-Fungal Activity

The present study aims to prepare and optimize butenafine hydrochloride NLCs formulation using solid and liquid lipid. The optimized selected BF-NLCopt was further converted into Carbopol-based gel for topical application for the treatment of fungal infection. Box Behnken design was employed to optimize the nanostructure lipids carriers (NLCs) using the lipid content (A), Tween 80 (B), and homogenization cycle (C) as formulation factors at three levels. Their effects were observed on the particle size (Y1) and entrapment efficiency (Y2). The selected formulation was converted into gel and further assessed for gel characterization, drug release, anti-fungal study, irritation study, and stability study. The solid lipid (Compritol 888 ATO), liquid lipid (Labrasol), and surfactant (tween 80) were selected based on maximum solubility. The optimization result showed a particle size of 111 nm with high entrapment efficiency of 86.35% for BF-NLCopt. The optimized BF-NLCopt converted to gel (1% w/v, Carbopol 934) and showed ideal gel evaluation results (drug content 99.45 ± 2.11, pH 6.5 ± 0.2, viscosity 519 ± 1.43 CPs). The drug release study result depicted a prolonged drug release (65.09 ± 4.37%) with high drug permeation 641.37 ± 46.59 µg (32.07 ± 2.32%) than BF conventional gel. The low value of irritation score (0.17) exhibited negligible irritation on the skin after application. The anti-fungal result showed greater efficacy than the BF gel at both time points. The overall conclusion of the results revealed NLCs-based gel of BF as an ideal delivery system to treat the fungal infection.

Low-dose repeated exposure to chemical surfactant impairs corneal epithelium: When personal cleaning products entering the eye

Studies have reported that the incidence of ocular discomfort in people who often wear makeup is higher than that in the normal population. The incidence of ocular discomfort of these people may be also related to the daily ocular exposure to chemical surfactants during cleaning. The objectives of this study were to explore morphological and pathological changes in the murine ocular surface after low-dose repeated exposure to disodium cocoamphodiacetate (DC), a kind of chemical surfactant widely used in personal cleaning products, and to investigate the possible mechanisms. DC was administered in low dose (0.1%) to the ocular surface of C56BL/6 once daily for two weeks. We found that there were an increase of sodium fluorescein staining on the cornea, a significant thinning of corneal epithelial thickness, and increased TUNEL-positive cells in corneal epithelium in vivo. DC treatment also modulated the distribution of K14⁺ and P63⁺ epithelia from the limbal to the center on the cornea. In cultured murine corneal epithelial progenitor cell line (TKE2), DC treatment induced cell detachment and decreased the activation of Ak strain transforming protein (AKT), and extracellular signal-regulated kinase (ERK). And DC increased TUNEL-positive cells in vitro with increased expression of cleaved Caspase3 and B-cell lymphoma-2 associated X protein (Bax). Our results indicated that repeated low-dose DC exposure on ocular surface caused significant impairment on the structure and viability of the corneal epithelium by inhibiting epithelial proliferation and inducing apoptosis. It provides the foundations to understand the harmful effects of cleaning products daily exposure on the ocular surface.

Effect of nonionic and amphoteric surfactants on salivary pellicles reconstituted in vitro

Surfactants are important components of oral care products. Sodium dodecyl sulfate (SDS) is the most common because of its foaming properties, taste and low cost. However, the use of ionic surfactants, especially SDS, is related to several oral mucosa conditions. Thus, there is a high interest in using non-ionic and amphoteric surfactants as they are less irritant. To better understand the performance of these surfactants in oral care products, we investigated their interaction with salivary pellicles i.e., the proteinaceous films that cover surfaces exposed to saliva. Specifically, we focused on pentaethylene glycol monododecyl ether (C12E5) and cocamidopropyl betaine (CAPB) as model nonionic and amphoteric surfactants respectively, and investigated their interaction with reconstituted salivary pellicles with various surface techniques: Quartz Crystal Microbalance with Dissipation, Ellipsometry, Force Spectroscopy and Neutron Reflectometry. Both C12E5 and CAPB were gentler on pellicles than SDS, removing a lower amount. However, their interaction with pellicles differed. Our work indicates that CAPB would mainly interact with the mucin components of pellicles, leading to collapse and dehydration. In contrast, exposure to C12E5 had a minimal effect on the pellicles, mainly resulting in the replacement/solubilisation of some of the components anchoring pellicles to their substrate.

Evaluating Hemolytic and Photo Hemolytic Potential of Organophosphorus by In Vitro Method as an Alternative Tool Using Human Erythrocytes

AIMS

The present study aims to determine the phototoxic and haemolytic activity of organophosphorus. The use of alternative in vitro assays with human erythrocytes is suggested to predict the polluting effect of these products on health.

METHODOLOGY

Human erythrocytes from Toluca Blood Bank were used. Sodium dodecyl sulfate was employed as a positive control. Additionally, the haemolysis percentage of three organophosphate (Acetate, Chlorpyrifos, Malathion, Methamidophos, Methyl Parathion) induced photo haemolysis formulated with surfactants on a concentration of 2 x 109 erythrocytes were evaluated. Finally, the products were classified as irritant or phototoxic.

RESULTS

Results showed that the HC50 red blood cells were similar for each organophosphate (Malathion and Methamidophos) indicating very irritant action with ratio classification (L/D) of 0.041 and 0.053, respectively. On the other hand, Chlorpyrifos was classified as an irritant with L/D= 0.14. On the other hand, the HC50 obtained photo hemolysis assays irradiated red blood cells was similar for each organophosphate (Acetate, Chlorpyrifos, Malathion, Methamidophos, Methyl Parathion) indicating no phototoxic action.

CONCLUSION

As a conclusion, it can be said that the parameters of haemolysis and denaturation of proteins are good indicators to classify organophosphorus formulated with surfactants as irritating or phototoxic.

Effect of nanoemulsion modification with chitosan and sodium alginate on the topical delivery and efficacy of the cytotoxic agent piplartine in 2D and 3D skin cancer models

Due to the limited options for topical management of skin cancer, this study aimed at developing and evaluating nanoemulsions (NE) for topical delivery of the cytotoxic agent piplartine (piperlongumine). NEs were modified with chitosan or sodium alginate, and the effects on the physicochemical properties, piplartine delivery and formulation efficacy were evaluated. The nanoemulsion droplets displayed similar size (96-112 nm), but opposite charge; the polysaccharides improved piplartine penetration into and across the skin (1.3-1.9-fold) in a similar manner, increasing the ratio "drug in the skin/receptor phase" by 1.4-1.5-fold compared to the plain NE and highlighting their relevance for cutaneous localization. Oleic acid addition to the chitosan-containing NE further increased drug penetration (~1.9-2.0-fold), as did increases in drug content from 0.5 to 1%. The cytotoxicity of piplartine was ~2.8-fold higher when the drug was incorporated in the chitosan-containing NE compared to its solution (IC50 = 14.6 μM) against melanoma cells. The effects of this nanocarrier on 3D melanoma tissues were concentration-related; at 1%, piplartine elicited marked epidermis destruction. These results support the potential applicability of the chitosan-modified nanoemulsion containing piplartine as a new strategy for local management of skin cancer.

Characterization and Cytotoxic Effect of Biosurfactants Obtained from Different Sources

In this work, five biosurfactant extracts, obtained from different sources, all of them with demonstrated antimicrobial properties, were characterized and subjected to a cytotoxic study using mouse fibroblast cells (NCTC clone 929). Biosurfactant extracts obtained directly from corn steep water (CSW) showed similar surfactant characteristics to those of the extracellular biosurfactant extract produced by Bacillus isolated from CSW and grown in tryptic soy broth, observing that they are amphoteric, consisting of viscous and yellowish liquid with no foaming capacity. Contrarily, cell-bound biosurfactant extracts produced from Lactobacillus pentosus or produced by Bacillus sp isolated from CSW are nonionic, consisting of a white powder with foaming capacity. All the biosurfactants possess a similar fatty acid composition. The cytotoxic test revealed that the extracts under evaluation, at a concentration of 1 g/L, were not cytotoxic for fibroblasts (fibroblast growth > 90%). The biosurfactant extract obtained from CSW with ethyl acetate, at 1 g/L, showed the highest cytotoxic effect but above the cytotoxicity limit established by the UNE-EN-ISO10993-5. It is remarkable that the cell-bound biosurfactant produced by L. pentosus, at a concentration of 1 g/L, promoted the growth of the fibroblast up to 113%.

Adsorption of Mixtures of a Pegylated Lipid with Anionic and Zwitterionic Surfactants at Solid/Liquid

This work explores the association of a pegylated lipid (DSPE-PEG) with different anionic and zwitterionic surfactants (pseudo-binary and pseudo-ternary polymer+ surfactant mixtures), and the adsorption of the polymer + surfactant aggregates onto negatively charged surfaces, with a surface charge density similar to that existing on the damaged hair epicuticle. Dynamic light scattering and zeta potential measurements shows that, in solution, the polymer + surfactant association results from an intricate balance between electrostatic and hydrophobic interactions, which leads to the formation of at least two different types of micellar-like polymer + surfactant aggregates. The structure and physicochemical properties of such aggregates were found strongly dependent on the specific nature and concentration of the surfactant. The adsorption of the polymer + surfactant aggregates onto negatively charged surface was studied using a set of surface-sensitive techniques (quartz crystal microbalance with dissipation monitoring, ellipsometry and Atomic Force Microscopy), which allows obtaining information about the adsorbed amount, the water content of the layers and the topography of the obtained films. Ion-dipole interactions between the negative charges of the surface and the oxyethylene groups of the polymer + surfactant aggregates appear as the main driving force of the deposition process. This is strongly dependent on the surfactant nature and its concentration, with the impact of the latter on the adsorption being especially critical when anionic surfactant are incorporated within the aggregates. This study opens important perspectives for modulating the deposition of a poorly interacting polymer onto negatively charged surfaces, which can impact in the fabrication on different aspects with technological and industrial interest.

In vivo biocompatibility and efficacy of dexamethasone-loaded PLGA-PEG-PLGA thermogel in an alkali-burn induced corneal neovascularization disease model

Challenges of ophthalmic drug delivery arise not only from the limited solubility of hydrophobic therapeutics, but also the restricted permeability and fast clearance of drugs due to the complex anatomy and physiology of eyes. Excellent biocompatibility of a thermosensitive polymer, PLGA-PEG-PLGA (1800-1500-1800, LA:GA ratio = 3:1), as an ophthalmic delivery system was demonstrated in our previous work. In this study, delivery of dexamethasone using this thermogel via a single subconjunctival injection for prolonged treatment was evaluated with corneal neovascularization using an alkali-burn diseased model in rat. Solubility of dexamethasone in the polymeric solution was increased by 5.2-fold and the resulting drug-loaded solution formed in situ rigid gel at body temperature. Prolonged in vitro release of dexamethasone from the gel structure was noted. Dexamethasone gel formulation was demonstrated to be more effective in reducing the burn stimulus and neovascularization in the rat diseased model. The findings suggest the PLGA-PEG-PLGA in situ gelling system can be applied for ophthalmic drug delivery to achieve sustained drug release and improved efficacy.

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

In vivo Raman spectroscopy study on the stimulation mechanism of surfactant

BACKGROUND

Surfactant is widely used in skin care products and cleansers, while it may cause physical discomfort. In this study, in vivo Raman spectroscopy was used to explore surfactant irritation mechanism on skin, which was not found in literature.

METHODS

Sodium dodecyl sulfate (SDS) was chosen to represent surfactant. Research on the negative effect of SDS was undertaken by scanning the two states of the skin (without and with the contact of SDS), respectively, on six volunteers, by means of Raman technique and skin magnifier.

RESULTS

The damage to the surface of normal skin by SDS was visible from the photographs taken by skin magnifier, and the apparent damage matched the damage that was happening underneath the skin elucidated by Raman spectra. Compared to the normal skin, the inter-cellular lipids (ICL) lateral packing order of the damaged skin was significantly reduced in 2-12 μm of skin depth (P < 0.05), deeper than 12 μm was not detected. The skin depth of 0-2 μm could not be determined due to strong interference of SDS. Significant change in the secondary and tertiary structures of keratin was not found.

Sodium N-lauryl amino acids derived from silk protein can form catanionic aggregates with cytarabine as novel anti-tumor drug delivery systems

A sodium N-lauryl amino acids (shortly silk sericin surfactant, SSS) is synthesized with lauryl chloride and sericin amino acids recovered from silk industrial waste. The purpose of this study is to explore whether the sericin surfactant can be used as a potential drug delivery carrier. By controlling the proportion of cationic drugs, cytarabine hydrochloride (CH) and anionic SSS, the aggregation behavior, slow release capability and toxicological effects of catanionic aggregates or vesicles, formed through CH and SSS, have been investigated in detail. Dynamic light scattering (DLS), transmission electron microscopy (TEM), and zeta potential analysis showed that the aggregate solution could form a stable vesicle structure when the mass fraction of CH is less than or equal to 0.3. The drug release results showed that the cumulative release rate of the catanionic aggregation solution with CH mass fraction of 0.2 reached a maximum at 18 h, being approximately 9 times greater than that of pure cytarabine. The CH/SSS aggregates had a significant sustained release effect compared with the control group. At the same time, vesicles formed by SSS and CH have better anti-tumor effects compared with the pure drug group. In summary, sericin surfactant from silk industrial waste has a potential use as a drug delivery carrier.

Preparation, characterisation and microbiological examination of Pickering nano-emulsions containing essential oils, and their effect on Streptococcus mutans biofilm treatment

Essential oils (EOs) are commonly applied in mouth care products like mouthwashes, mostly as an ethanolic solution or by usage of surfactants as solubilising agents. In this study, we present a formulation for preparation of Pickering nano-emulsions (PnE) of EOs as a novel form for application of EOs in mouth care. For the preparation of PnE, we have synthesised surface-modified silica nanoparticles with a mean diameter of 20 nm, as well as we have examined the effect of EOs concentration on PnE droplet size and stability. In vitro study of their effect on the Streptococcus mutans biofilm as the main pathogen of dental health problems has been performed. We have found that EOs in the PnE form has the highest effectiveness against biofilm formation. Diffusion through the biofilm model membrane was studied to explain this observation. We have found that PnEs have a better performance in the transportation of EOs trough model membrane than the ethanolic solutions and conventional emulsions (CEs).

Subcritical Methanolysis of Starch and Transglycosidation to Produce Dodecyl Polyglucosides

Biosurfactants based on carbohydrates are of special interest because of their production from renewable resources, nontoxicity, biocompatibility, and environmental friendliness. Dodecyl polyglucosides, a type of nonionic surfactant synthesized with methyl polyglucosides obtained from the eco-friendly subcritical methanolysis of renewable resource of starch, is no doubt good for ecosystem. With the subcritical methanolysis of starch, the methyl polyglucosides were obtained without any catalyst. Under the reaction condition of the weight ratio of methanol to starch of 7.5, temperature of 220 °C, and reaction time of 2 h, the yield of methyl polyglucosides was 85%. Dodecyl polyglucosides were synthesized by transglycosidation with methyl polyglucosides, and the green nonionic surfactant has excellent surface activity. The critical micelle concentration and hydrophilic lipophilic balance are 0.022 wt % and 12, respectively.

Optimization of composition and obtainment parameters of biocompatible nanoemulsions intended for intraductal administration of piplartine (piperlongumine) and mammary tissue targeting

As a new strategy for treatment of ductal carcinoma in situ, biocompatible and bioadhesive nanoemulsions for intraductal administration of the cytotoxic agent piplartine (piperlongumine) were optimized in this study. To confer bioadhesive properties, the nanoemulsion was modified with chitosan or hyaluronic acid. Tricaprylin was selected as the nanoemulsion non-polar phase due to its ability to dissolve larger drug amounts compared to isopropyl myristate and monocaprylin. Use of phosphatidylcholine as sole surfactant did not result in a homogeneous nanoemulsion, while its association with polysorbate 80 and glycerol (in a surfactant blend) led to the formation of nanoemulsions with droplet size of 76.5 ± 1.2 nm. Heating the aqueous phase to 50 °C enabled sonication time reduction from 20 to 10 min. Inclusion of either chitosan or hyaluronic acid resulted in nanoemulsions with similar in vitro bioadhesive potential, and comparable ability to prolong mammary tissue retention (to 120 h) in vivo without causing undesirable histological alterations. Piplartine was stable in both nanoemulsions for 60 days; however, the size of loaded NE-HA was maintained at a similar range for longer periods of time, suggesting that this nanoemulsion may be a stronger candidate for intraductal delivery.

Preservative and Irritant Capacity of Biosurfactants From Different Sources: A Comparative Study

One of the most important challenges for pharmaceutical and cosmetic industries is solubilization and preservation of their active ingredients. Therefore, most of these formulations contain irritant chemical additives to improve their shelf-life and the solubility of hydrophobic ingredients. An interesting alternative to chemical surfactants and preservatives is the use of biosurfactants; thus, their surfactant properties and composition make them more biocompatible than their chemical counterparts. Moreover, some biosurfactants have shown antimicrobial activity in addition to their detergent capacity. In this work, the antimicrobial and irritant effect of 2 biosurfactant extracts was studied: one produced in a controlled fermentation process with Lactobacillus pentosus and the other produced from corn stream by spontaneous fermentation. The results showed a strong antimicrobial activity of the biosurfactant extract obtained from corn stream on pathogenic bacteria, in comparison with the L. pentosus biosurfactant extract. Moreover, both biosurfactants did not produce any irritant effect on the chorioallantoic membrane of hen's egg assay contrary to sodium dodecyl sulfate. This is the first study dealing with the application of biosurfactant extracts on sensitive biological membranes, and this is the first time that the preservative capacity of a biosurfactant extract obtained in spontaneous fermentation is being evaluated, achieving promising results.

Multifunctional nanoemulsions for intraductal delivery as a new platform for local treatment of breast cancer

Considering that breast cancer usually begins in the lining of the ducts, local drug administration into the ducts could target cancers and pre-tumor lesions locally while reducing systemic adverse effects. In this study, a cationic bioadhesive nanoemulsion was developed for intraductal administration of C6 ceramide, a sphingolipid that mediates apoptotic and non-apoptotic cell death. Bioadhesive properties were obtained by surface modification with chitosan. The optimized nanoemulsion displayed size of 46.3 nm and positive charge, properties that were not affected by ceramide encapsulation (0.4%, w/w). C6 ceramide concentration necessary to reduce MCF-7 cells viability to 50% (EC₅₀) decreased by 4.5-fold with its nanoencapsulation compared to its solution; a further decrease (2.6-fold) was observed when tributyrin (a pro-drug of butyric acid) was part of the oil phase of the nanocarrier, a phenomenon attributed to synergism. The unloaded nanocarrier was considered safe, as indicated by a score <0.1 in HET-CAM models, by the high survival rates of Galleria mellonella larvae exposed to concentrations ≤500 mg/mL, and absence of histological changes when intraductally administered in rats. Intraductal administration of the nanoemulsion prolonged drug localization for more than 120 h in the mammary tissue compared to its solution. These results support the advantage of the optimized nanoemulsion to enable mammary tissue localization of C6 ceramide.

Interactions between surfactants and the skin - Theory and practice

One of the primary causes of skin irritation is the use of body wash cosmetics and household chemicals, since they are in direct contact with the skin, and they are widely available and frequently used. The main ingredients of products of this type are surfactants, which may have diverse effects on the skin. The skin irritation potential of surfactants is determined by their chemical and physical properties resulting from their structure, and specific interactions with the skin. Surfactants are capable of interacting both with proteins and lipids in the stratum corneum. By penetrating through this layer, surfactants are also able to affect living cells in deeper regions of the skin. Further skin penetration may result in damage to cell membranes and structural components of keratinocytes, releasing proinflammatory mediators. By causing irreversible changes in cell structure, surfactants can often lead to their death. The paper presents a critical review of literature on the effects of surfactants on the skin. Aspects discussed in the paper include the skin irritation potential of surfactants, mechanisms underlying interactions between compounds of this type and the skin which have been proposed over the years, and verified methods of reducing the skin irritation potential of surfactant compounds. Basic research conducted in this field over many years translate into practical applications of surfactants in the cosmetic and household chemical industries. This aspect is also emphasized in the present study.

Hydrophilic Dogwood Extracts as Materials for Reducing the Skin Irritation Potential of Body Wash Cosmetics

A significant problem related to the use of surfactants in body wash cosmetics is their propensity to trigger skin irritations. Only scarce literature exists on the effect of plant extracts on the skin irritation potential. The present study is an attempt to determine the effect of hydrophilic dogwood extracts on the irritant potential of body wash gels. Extractants used in the study were water and mixtures of water with glycerine, water with trimethylglycine (betaine), and water with plant-derived glycol (propanediol). The basic biochemical properties, i.e., the ability to neutralize free radicals, and the content of polyphenols, anthocyanins and flavonoids, were determined. An attempt was undertaken to analyze the impact of the extract added to natural body wash gel formulations on product properties. The skin irritation potential was assessed by determining the zein number and the increase in the pH level of the bovine serum albumin (BSA) solution. The viscosity and foaming ability of the resulting products were evaluated. The studies revealed that an addition of dogwood extract contributes to an improvement in the properties of body wash gels and significantly increases the safety of product use through reducing the skin irritation effect.

Co-Formulants in Glyphosate-Based Herbicides Disrupt Aromatase Activity in Human Cells below Toxic Levels

Pesticide formulations contain declared active ingredients and co-formulants presented as inert and confidential compounds. We tested the endocrine disruption of co-formulants in six glyphosate-based herbicides (GBH), the most used pesticides worldwide. All co-formulants and formulations were comparably cytotoxic well below the agricultural dilution of 1% (18-2000 times for co-formulants, 8-141 times for formulations), and not the declared active ingredient glyphosate (G) alone. The endocrine-disrupting effects of all these compounds were measured on aromatase activity, a key enzyme in the balance of sex hormones, below the toxicity threshold. Aromatase activity was decreased both by the co-formulants alone (polyethoxylated tallow amine-POEA and alkyl polyglucoside-APG) and by the formulations, from concentrations 800 times lower than the agricultural dilutions; while G exerted an effect only at 1/3 of the agricultural dilution. It was demonstrated for the first time that endocrine disruption by GBH could not only be due to the declared active ingredient but also to co-formulants. These results could explain numerous in vivo results with GBHs not seen with G alone; moreover, they challenge the relevance of the acceptable daily intake (ADI) value for GBHs exposures, currently calculated from toxicity tests of the declared active ingredient alone.

Critical appraisal of alternative irritation models: three decades of testing ophthalmic pharmaceuticals

BACKGROUND

Testing ocular tolerability of ocular pharmaceuticals is an essential regulatory requirement. The current approved reference model (gold standard) for ocular irritation testing is the Draize test. However this method is subjective and involves using live animals, hence the need to develop alternative in vitro and ex vivo testing strategies.

SOURCE OF DATA

Pubmed, Science Direct, Scopus, Google Scholar, Medline, Current Content, Web of Science and validation reports from international regulatory bodies; The Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) and European Centre for the Validation of Alternative Methods (ECVAM) were searched for in vitro alternatives.

AREA OF AGREEMENT

Whilst no single in vitro test can effectively replace the Draize eye irritation test, regulatory bodies and cosmetic/pharmaceutical industries agree that there is a need for in vitro alternatives with validated endpoints to evaluate pharmaceutical ingredients and finished eye products.

AREA OF CONTROVERSY

There is no single in vitro test / assay that can predict the ocular irritation potential of mild to moderate test substances.

AREA TIMELY FOR DEVELOPING RESEARCH

This review provides a critical appraisal of the selected in vitro and ex vivo ocular toxicity models recommended by international regulatory bodies. These include cytotoxicity methods, biochemical systems and ex vivo assays. The latter are approved by ECVAM as in vitro alternatives for the well-known Draize test. Hen's egg test-chorioallantoic membrane and the isolated rabbit eye test are also accepted by regulatory agencies in France, Germany, the Netherlands and the UK. A combination of ex vivo assays along with histological examination of excised bovine cornea can predict the conjunctival and corneal tolerability and cover a wider range of ocular pharmaceutical substances.

Overcoming the cutaneous barrier with microemulsions

Microemulsions are fluid and isotropic formulations that have been widely studied as delivery systems for a variety of routes, including the skin. In spite of what the name suggests, microemulsions are nanocarriers, and their use as topical delivery systems derives from their multiple advantages compared to other dermatological formulations, such as ease of preparation, thermodynamic stability and penetration-enhancing properties. Composition, charge and internal structure have been reported as determinant factors for the modulation of drug release and cutaneous and transdermal transport. This manuscript aims at reviewing how these and other characteristics affect delivery and make microemulsions appealing for topical and transdermal administration, as well as how they can be modulated during the formulation design to improve the potential and efficacy of the final system.

Safety Assessment of Decyl Glucoside and Other Alkyl Glucosides as Used in Cosmetics

The Cosmetic Ingredient Review (CIR) Expert Panel assessed the safety of 19 alkyl glucosides as used in cosmetics and concluded that these ingredients are safe in the present practices of use and concentration when formulated to be nonirritating. Most of these ingredients function as surfactants in cosmetics, but some have additional functions as skin-conditioning agents, hair-conditioning agents, or emulsion stabilizers. The Panel reviewed the available animal and clinical data on these ingredients. Since glucoside hydrolases in human skin are likely to break down these ingredients to release their respective fatty acids and glucose, the Panel also reviewed CIR reports on the safety of fatty alcohols and were able to extrapolate data from those previous reports to support safety.

Formation and stability of oil-in-water nanoemulsions containing rice bran oil: in vitro and in vivo assessments

BACKGROUND

Nanoemulsions have practical application in a multitude of commercial areas, such as the chemical, pharmaceutical and cosmetic industries. Cosmetic industries use rice bran oil in sunscreen formulations, anti ageing products and in treatments for skin diseases. The aim of this study was to create rice bran oil nanoemulsions using low energy emulsification methods and to evaluate their physical stability, irritation potential and moisturising activity on volunteers with normal and diseased skin types.

RESULTS

The nanoemulsion developed by this phase diagram method was composed of 10% rice bran oil, 10% surfactants sorbitan oleate/PEG-30 castor oil, 0.05% antioxidant and 0.50% preservatives formulated in distilled water. The nanoemulsion was stable over the time course of this study. In vitro assays showed that this formulation has a low irritation potential, and when applied to human skin during in vivo studies, the nanoemulsion improved the skin's moisture and maintained normal skin pH values.

CONCLUSION

The results of irritation potential studies and in vivo assessments indicate that this nanoemulsion has potential to be a useful tool to treat skin diseases, such as atopic dermatitis and psoriasis.

Transdermal delivery of an anti-cancer drug via w/o emulsions based on alkyl polyglycosides and lecithin: design, characterization, and in vivo evaluation of the possible irritation potential in rats

The purpose of this work was to develop w/o emulsions that could be safely used to promote transdermal delivery of 5-fluorouracil (5-FU). Two pseudo-ternary phase diagrams comprising oleoyl-macrogol glycerides, water, and a surfactant/co-surfactant (S/CoS) mixture of lecithin, ethanol, and either coco glucoside or decyl glucoside were investigated for their potential to develop promising 5-FU emulsions. Six systems were selected and subjected to thermodynamic stability tests; heat-cool cycles, centrifugation, and finally freeze-thaw cycles. All systems passed the challenges and were characterized for transmission electron microscopy, droplet size, rheological behavior, pH, and transdermal permeation through newly born mice skin in Franz diffusion cells. The systems had spherical droplets ranging in diameter from 1.81 to 2.97 μm, pH values ranging from 7.50 to 8.49 and possessed Newtonian flow. A significant (P<0.05) increase in 5-FU permeability parameters as steady-state flux, permeability coefficient was achieved with formula B5 comprising water (5% w/w), S/CoS mixture of lecithin/ethanol/decyl glucoside (14.67:12.15:18.18% w/w, respectively) and oleoyl-macrogol glycerides (50% w/w). When applied to shaved rat skin, this system was well tolerated with only moderate skin irritation that was recovered within 12 h. Indeed, minor histopathologic changes were observed after 5-day treatment. Further studies should be carried out, in the future, to investigate the potentiality of this promising system to promote transdermal delivery of 5-FU through human skin.

Combined In Vitro Tests as an Alternative to In Vivo Eye Irritation Tests

Accurate methods that test the eye irritation potential of chemicals, which do not involve the use of animals, are needed to meet new regulatory standards. We evaluated the applicability and predictive capacity of five in vitro tests for eye irritation: the Hen's Egg Test-Chorioallantoic Membrane (HET-CAM) assay; the Chorioallantoic Membrane-Trypan Blue Staining (CAM-TBS) assay; the Fluorescein Leakage Test (FLT); the 3T3-Neutral Red Uptake (3T3-NRU) cytotoxicity assay; and the red blood cell (RBC) haemolysis assay. A panel of 16 chemicals (some at multiple concentrations) was assessed by using the five tests, and the results were compared with historical in vivo Draize test data. The results showed rank correlation and class concordance between the five alternative methods and the Draize test for the 16 chemicals. These in vitro assays had good predictive capacity, reproducibility and reliability when compared to the Draize test. The best relationship was between the HET-CAM, CAM-TBS and FLT results, and the modified maximum average score(s) (MMAS). A prediction model (PM) was developed, based on the maximum possible correlation between the MMAS and the HET-CAM, CAM-TBS and FLT results. The PM had a good predictive capacity when compared to the results of animal tests, indicating its potential value for the in vitro screening of chemicals for eye irritation effects.

Comparative study of the ocular irritation potential of various alkyl polyglucoside surfactants

In the present work, we assessed the relationship between alkyl carbon chain length and ocular irritation potentials using the hen's egg test-chorioallantoic membrane (HET-CAM) and bovine corneal opacity and permeability (BCOP) assays using 5 commercial alkyl polyglucoside surfactants with different compositions of alkyl chain lengths (C(6)-C(16)). With HET-CAM, there was a good correlation between the proportion of C(10) alkyl polyglucoside and the eye irritation potential Q score (r(2) = 0.912, p = .011). There were no significant differences between the proportion of C(10) alkyl polyglucoside and corneal opacity in BCOP assays; however, there was a relatively high positive correlation between the proportion of C(10) alkyl carbon chain lengths and corneal permeability (r(2) = 0.736, p = .063).

In vitro assessment of eye irritancy using the Reconstructed Human Corneal Epithelial SkinEthic HCE model: application to 435 substances from consumer products industry

The 7th amendment of the EU Cosmetics Directive led to the ban of eye irritation testing for cosmetic ingredients in animals, effective from March 11th 2009. Over the last 20years, many efforts have been made to find reliable and relevant alternative methods. The SkinEthic HCE model was used to evaluate the in vitro eye irritancy potential of substances from a cosmetic industry portfolio. An optimized protocol based on a specific 1-h treatment and a 16-h post-treatment incubation period was first assessed on a set of 102 substances. The prediction model (PM) based on a 50% viability cut-off, allowed to draw up two classes (Irritants and Non-Irritants), with good associated sensitivity (86.2%) and specificity (83.5%). To check the robustness of the method, the evaluated set was expanded up to 435 substances. Final performances maintained a high level and were characterized by an overall accuracy value > 82% when using EU or GHS classification rules. Results showed that the SkinEthic HCE test method is a promising in vitro tool for the prediction of eye irritancy. Optimization datasets were shared with the COLIPA Eye Irritation Project Team and ECVAM experts, and reviewed as part of an ongoing progression to enter an ECVAM prospective validation study for eye irritation.

Engineering tissue alternatives to animals: applying tissue engineering to basic research and safety testing

The focus for the rapid progress in the field of tissue engineering has been the clinical potential of the technology to repair, replace, maintain or enhance the function of a particular tissue or organ. However, tissue engineering has much wider applicability in basic research and safety testing, which is often not recognized owing to the clinical focus of tissue engineers. Using examples from a recent National Centre for the Replacement, Refinement and Reduction of Animals in Research/Biotechnology and Biological Sciences Research Council symposium, which brought together tissue engineers and scientists from other research communities, this review highlights the potential of tissue engineering to provide scientifically robust alternatives to animals to address basic research questions and improve drug and chemical development in the pharmaceutical and chemical industries.

Washing of field weathered crude oil contaminated soil with an environmentally compatible surfactant, alkyl polyglucoside

Weathered crude oil contaminated soils (COCSs), which are much more difficult to remediate than those freshly contaminated, are widespread especially at the sites of oil fields and industries. Surfactant enhanced ex situ soil washing could be used to remediate COCSs, but surfactant toxicity becomes one of the major concerns. In this study, a class of green surfactants, alkyl polyglucosides (APGs), were tested in washing the field weathered COCS with relatively high oil concentration (123 mgg(-1) dry soil) from Jilin Oilfield, Northeastern China. APG1214, characterized with longer alkyl chain, was more effective than APG0810 in crude oil removal. Adding inorganic sodium salts into APG1214 solution further improved the crude oil removal efficiency (CORE). Washing parameters (temperature, washing time, agitation speed and solution/soil ratio) were investigated and further optimized integratedly with an orthogonal design. At the optimum conditions, the CORE reached 97%. GC/MS analysis showed that the proportion of small n-alkanes (C(16)-C(23)) in residual crude oil gradually increased, which was helpful to interpret the oil removal mechanism. Moreover, eminent effect on removal of large n-alkanes was achieved from the synergy between APG1214 and inorganic salts, which was opposite to the effect when they were added separately. This study demonstrated a promising way to remediate COCS with ecologically compatible surfactant and provided guidelines for its practical application.