HET-CAM test. Application to shampoos in developing countries

Protium spruceanum Extract Enhances Mupirocin Activity When Combined with Nanoemulsion-Based Hydrogel: A Multi-Target Strategy for Treating Skin and Soft Tissue Infections

The treatment of skin and soft tissue infections (SSTIs) can be challenging due to bacterial resistance, particularly from strains like MRSA and biofilm formation. However, combining conventional antibiotics with natural products shows promise in treating SSTIs. The objective of this study is to develop a nanoemulsion-based hydrogel containing Protium spruceanum extract and mupirocin and evaluate its potential for the treatment of SSTIs. The nanoemulsion was obtained by phase inversion and subsequently characterized. The antibacterial activity was evaluated in vitro against S. aureus MRSA, including the synergism of the combination, changes in membrane permeability using flow cytometry, and the anti-biofilm effect. In addition, the irritative potential was evaluated by the HET-CAM assay. The combination exhibited synergistic antibacterial activity against S. aureus and MRSA due to the extract enhancing membrane permeability. The hydrogel demonstrated suitable physicochemical properties, inhibited biofilm formation, and exhibited low irritation. The formulation was nanometric (176.0 ± 1.656 nm) and monodisperse (polydispersity index 0.286 ± 0.011). It exhibited a controlled release profile at 48 h and high encapsulation efficacy (94.29 ± 4.54% for quercitrin and 94.20 ± 5.44% for mupirocin). Therefore, these findings suggest that the hydrogel developed could be a safe and effective option for treating SSTIs.

Riluzole-Loaded Nanostructured Lipid Carriers for Hyperproliferative Skin Diseases

Nanocarriers, and especially nanostructured lipid carriers (NLC), represent one of the most effective systems for topical drug administration. NLCs are biodegradable, biocompatible and provide a prolonged drug release. The glutamate release inhibitor Riluzole (RLZ) is a drug currently used for amyotrophic lateral sclerosis (ALS), with anti-proliferative effects potentially beneficial for diseases with excessive cell turnover. However, RLZ possesses low water solubility and high light-sensibility. We present here optimized NLCs loaded with RLZ (RLZ-NLCs) as a potential topical treatment. RLZ-NLCs were prepared by the hot-pressure homogenization method using active essential oils as liquid lipids, and optimized using the design of experiments approach. RLZ-NLCs were developed obtaining optimal properties for dermal application (mean size below 200 nm, negative surface charge and high RLZ entrapment efficacy). In vitro release study demonstrates that RLZ-NLCs allow the successful delivery of RLZ in a sustained manner. Moreover, RLZ-NLCs are not angiogenic and are able to inhibit keratinocyte cell proliferation. Hence, a NLCs delivery system loading RLZ in combination with natural essential oils constitutes a promising strategy against keratinocyte hyperproliferative conditions.

In vitro eye irritation testing models may play pivotal role in effort to pursue mild baby cleansers

In recent years, mild baby cleansers have experienced ever-growing demand from caregivers. In the meantime, formulation developers are in practical need for a method(s) to screen mild formulations. In the present study, we aim to repurpose the HET-CAM and SkinEthic™ models to further classify in vivo nonirritant baby cleansing formulations into mild and less mild categories. Both methods were modified to best describe the samples' irritation potential. The results showed that both models successfully classified the formulations into mild and less mild categories according to our customized criteria. For the HET-CAM, the medians of mean irritation scores (IS) were 3.0 for mild formulations (with 0 ≤ mean IS ≤4.5), and 5.0 for less mild formulations (with mean IS values all equaled 5), respectively. And for the SkinEthic™ model, the median relative viabilities were 69.46% for less mild formulations (with 46.80% ≤ mean relative viability ≤84.76%), and 99.96% for mild formulations (with 90.57% ≤ mean relative viability ≤124.58%). Thirty out of 35 formulations were predicted consistently between the HET-CAM and SkinEthic™ model. Statistical analysis of the agreement between predictions made by the two models demonstrated substantial agreement with a Cohen's kappa coefficient of 0.713 (P < 0.001). We conclude that the HET-CAM and SkinEthic™ models are promising in vitro alternatives for screening mild formulations.

From the PnTx2-6 Toxin to the PnPP-19 Engineered Peptide: Therapeutic Potential in Erectile Dysfunction, Nociception, and Glaucoma

The venom of the “armed” spider Phoneutria nigriventer comprises several potent toxins. One of the most toxic components from this venom is the neurotoxin PnTx2-6 (LD50 = ∼ 0.7 μg/mouse, 48 residues, five disulfide bridges, MW = 5,289.31 Da), which slows down the inactivation of various Na+ channels. In mice and rats, this toxin causes priapism, an involuntary and painful erection, similar to what is observed in humans bitten by P. nigriventer. While not completely elucidated, it is clear that PnTx2-6 potentiates erectile function via NO/cGMP signaling, but it has many off-target effects. Seeking to obtain a simpler and less toxic molecule able to retain the pharmacological properties of this toxin, we designed and synthesized the peptide PnPP-19 (19 residues, MW = 2,485.6 Da), representing a discontinuous epitope of PnTx2-6. This synthetic peptide also potentiates erectile function via NO/cGMP, but it does not target Na+ channels, and therefore, it displays nontoxic properties in animals even at high doses. PnPP-19 effectively potentiates erectile function not only after subcutaneous or intravenous administration but also following topical application. Surprisingly, PnPP-19 showed central and peripheral antinociceptive activity involving the opioid and cannabinoid systems, suggesting applicability in nociception. Furthermore, considering that PnPP-19 increases NO availability in the corpus cavernosum, this peptide was also tested in a model of induced intraocular hypertension, characterized by low NO levels, and it showed promising results by decreasing the intraocular pressure which prevents retinal damage. Herein, we discuss how was engineered this smaller active non-toxic peptide with promising results in the treatment of erectile dysfunction, nociception, and glaucoma from the noxious PnTx2-6, as well as the pitfalls of this ongoing journey.

Development of topical eye-drops of lactoferrin-loaded biodegradable nanoparticles for the treatment of anterior segment inflammatory processes

Ocular inflammation is one of the most common comorbidities associated to ophthalmic surgeries and disorders. Since conventional topical ophthalmic treatments present disadvantages such as low bioavailability and relevant side effects, natural alternatives constitute an unmet medical need. In this sense, lactoferrin, a high molecular weight protein, is a promising alternative against inflammation. However, lactoferrin aqueous instability and high nasolacrimal duct drainage compromises its potential effectiveness. Moreover, nanotechnology has led to an improvement in the administration of active compounds with compromised biopharmaceutical profiles. Here, we incorporate lactoferrin into biodegradable polymeric nanoparticles and optimized the formulation using the design of experiments approach. A monodisperse nanoparticles population was obtained with an average size around 130 nm and positive surface charge. Pharmacokinetic and pharmacodynamic behaviour were improved by the nanoparticles showing a prolonged lactoferrin release profile. Lactoferrin nanoparticles were non-cytotoxic and non-irritant neither in vitro nor in vivo. Moreover, nanoparticles exhibited significantly increased anti-inflammatory efficacy in cell culture and preclinical assays. In conclusion, lactoferrin loaded nanoparticles constitute a safe and novel nanotechnological tool suitable for the treatment of ocular inflammation.

Comparison of the different protocols of the Hen's Egg Test-Chorioallantoic Membrane (HET-CAM) by evaluating the eye irritation potential of surfactants

The Hen's Egg Test - Chorioallantoic Membrane (HET-CAM) is a valid alternative method used to assess the potential for eye irritation from chemicals. This method is the only one that mimics the conjunctivae of the eye and aims to semi-quantitatively evaluate the irritant potential of a chemical on the chorioallantoic membrane surrounding the chicken embryo in egg by observing the irritation effects on the membrane immediately after the pure or diluted chemical is applied. The purpose of this study was to compare the different protocols of the HET-CAM, the French and German protocols, by evaluating the eye irritation potential of surfactants. The comparison led to the optimization of the French protocol, generating an adapted one, to reduce subjectivity in the test evaluation, ensuring more accurate results and greater quality control. The comparison showed that there are no significant differences between the results obtained in the French and German protocols. HET-CAM is known to overestimate the results and to be able to accurately identify non-irritant products and it is a great candidate to be part of a Bottom-up test strategy. It also can be used in a battery of tests to completely replace rabbits.

Development of Lactoferrin-Loaded Liposomes for the Management of Dry Eye Disease and Ocular Inflammation

Dry eye disease (DED) is a high prevalent multifactorial disease characterized by a lack of homeostasis of the tear film which causes ocular surface inflammation, soreness, and visual disturbance. Conventional ophthalmic treatments present limitations such as low bioavailability and side effects. Lactoferrin (LF) constitutes a promising therapeutic tool, but its poor aqueous stability and high nasolacrimal duct drainage hinder its potential efficacy. In this study, we incorporate lactoferrin into hyaluronic acid coated liposomes by the lipid film method, followed by high pressure homogenization. Pharmacokinetic and pharmacodynamic profiles were evaluated in vitro and ex vivo. Cytotoxicity and ocular tolerance were assayed both in vitro and in vivo using New Zealand rabbits, as well as dry eye and anti-inflammatory treatments. LF loaded liposomes showed an average size of 90 nm, monomodal population, positive surface charge and a high molecular weight protein encapsulation of 53%. Biopharmaceutical behaviour was enhanced by the nanocarrier, and any cytotoxic effect was studied in human corneal epithelial cells. Developed liposomes revealed the ability to reverse dry eye symptoms and possess anti-inflammatory efficacy, without inducing ocular irritation. Hence, lactoferrin loaded liposomes could offer an innovative nanotechnological tool as suitable approach in the treatment of DED.

The chick embryo chorioallantoic membrane model: a research approach for ex vivo and in vivo experiments

BACKGROUND

The chick chorioallantoic membrane (CAM) model has attracted a great deal of interest in pharmaceutical and biological research as an alternative or complementary in vivo assay to animal models. Traditionally, CAM assay has been widely used to perform some toxicological studies, specifically to evaluate the skin, ocular and embryo toxicity of new drugs and formulations, and perform angiogenesis studies. Due to the possibility to generate the tumors onto the CAM, this model has also become an excellent strategy to evaluate the metastatic potential of different tumours and test the efficacy of novel anticancer therapies in vivo. Moreover, in the recent years, its use has considerably grown in other research areas, including the evaluation of new anti-infective agents, the development of biodistribution studies and tissue engineering research.

OBJECTIVES

This manuscript provides a critical overview of the use of CAM model in pharmaceutical and biological research, especially to test the toxicity of new drugs and formulations and the biodistribution and the efficacy of novel anticancer and anti-infective therapies, analyzing its advantages and disadvantages compared to animal models.

CONCLUSION

The chick chorioallantoic membrane model shows great utility in several research areas, such as cancer, toxicology, biodistribution studies and anti-infective therapies. In fact, it has become an intermediate stage between in vitro experiments and animal studies, and, in the case of toxicological studies (skin and ocular toxicity), has even replaced the animal models.

Application of in vitro methods to evaluate the safety of baby care products

Draize rabbit eye irritation and skin irritation tests are widely used in the chemical industry as traditional methods to evaluate the safety of cosmetics. However, great differences among laboratories have caused great doubt in the industry. In addition, with vigorous development of the global animal protection movement, developed countries have launched the "3R" campaign, and various kinds of in vitro alternative methods have emerged. Hen's egg test on the chorioallantoic membrane (HET-CAM), which is similar to the structure of the human cornea and has a clear and complete vascular system, is based on the characteristics of the chorioallantoic membrane (CAM) in mid-term SPF egg embryos. The reconstructed human epidermis (EpiSkin®) is composed of normal human keratinocytes that are histologically similar to human epidermises seen in vivo, and it is cultured on a collagen matrix. Similar to EpiSkin®, Human Corneal Epithelium (SkinEthic™) is another reconstructed 3D human-corneal structure that is an alternative to the traditional eye irritation test. Three in vitro methods were conducted to evaluate the safety of 12 baby care products, which included the most common types. In addition, a consumer research study was also carried out for two weeks to evaluate the safety. The results of the reconstructed human epidermis model, human corneal epithelium model and consumer research showed that no irritation was found in any test products; however, HET-CAM tests showed positive results.

Comparison between HET-CAM protocols and a product use clinical study for eye irritation evaluation of personal care products including cosmetics according to their surfactant composition

The hen's egg test on chorioallantoic membrane (HET-CAM) is one of the most frequently used alternative tests for prediction of ocular irritation of cosmetic products. There are different HET-CAM protocols widely accepted, but there is no information about which of the protocols better correlates with the results obtained in product use clinical study under the conditions of use. Two Fix Time Methods (FTM) -Lüepke and the ICCVAM guideline - and two Reaction Time Methods (RTM) -ECVAM DBALM Prot. No. 47 and No. 96- were employed to test 18 cosmetic products. Simultaneously, they were evaluated by an ophthalmological clinical test. A unified classification system was used, and products were classified into four irritation levels: non-irritant, weak, moderate and severe irritant. The duration of use (rinse-off or leave-on), and the concentration and type of surfactants were taken into account in the analysis. All the products that were classified as non-irritant by any HET-CAM protocols were also safe in the product use clinical study. The product that was found to be non-safe in the product use clinical evaluation was also unsuitable by most of the HET-CAM protocols. These results were employed to develop an algorithm that allows selecting the appropriate HET-CAM protocol for each type of product to be tested.

Comparative evaluation of HET-CAM and ICE methods for objective assessment of ocular irritation caused by selected pesticide products

Eye irritation potency of pesticides (fungicides, herbicides, insecticides) was comparatively tested by HET-CAM and ICE method. Based on the results of the tests the statistical analysis of agreement between classification using individual methods was done by Goodman-Kruskal's rank correlation and determination (calculation) of Cohen's kappa coefficient. Statistical analysis of agreement between classification revealed significant correlation between results of in vivo and in HET-CAM assays (76%). There was no significant correlation between result of in vivo and in ICE methods (64%). Weakest correlation was found between the data from in vitro HET-CAM and ICE tests. The percentage of agreement between two in vitro data was 48%. They may be recommended as a part of a battery of tests to reduce experimentation on mammals and to limit or eliminate pain and injury inflicted on experimental animals. The HET-CAM test is a useful tool for studying in vivo the potential conjunctival irritation, while the ICE test can be used to study corneal irritant effects in detail.

Biocompatibility of the 8.25% sodium hypochlorite irrigant solution in endodontics: An in vivo study

The biocompatibility of irrigant solutions, including 8.25% sodium hypochlorite (NaOCl), was analyzed in samples (n = 25) of chorioallantoic membranes (CAM) from embryos of the Gallus gallus, using the hen's egg test on chorioallantoic membrane (HET-CAM). The following irrigants were tested: saline (control), 2% chlorhexidine (2% CHX), and NaOCl (2.5%, 5.25%, and 8.25%), and morphological and microcirculatory changes were investigated. Images were selected and quantified with Image J®. The macroscopic data were submitted to ANOVA, followed by the Tukey's test (p < .05); non-parametric Kruskal-Wallis and Mann-Whitney tests were applied to histological data (p < .05). The frequency of hyperemia differed significantly in the 8.25% NaOCl compared to the other groups, with the exception of 5.25% NaOCl (p = .096). Coagulation was more frequent in the 2% CHX group, differing significantly from the 2.5% NaOCl group (p = .038). In mean values, NaOCl 8.25% caused the decrease (NaOCl = 2.60, and control = 5.00) of vessels in the microcirculation, as well as triggered the increase (NaOCl = 425.50, and control 44.50) of inflammatory cells in the observed areas. There was necrosis in all samples in the 5.25% NaOCl group and in 80% in the 2% CHX, 2.5% NaOCl, and 8.25% NaOCl groups. Fibroblasts were detected only in the control group. It was concluded that the 8.25% NaOCl solution showed significantly high toxicity on CAM. However, these results were comparable to the other concentrations of NaOCl and to 2% CHX. Thus, in this experimental protocol, 8.25% NaOCl proved to be viable as an irrigant solution.

Acute, reproductive, and developmental toxicity of essential oils assessed with alternative in vitro and in vivo systems

Essential oils (EOs) have attracted increased interest for different applications such as food preservatives, feed additives and ingredients in cosmetics. Due to their reported variable composition of components, they might be acutely toxic to humans and animals in small amounts. Despite the necessity, rigorous toxicity testing in terms of safety evaluation has not been reported so far, especially using alternatives to animal models. Here, we provide a strategy by use of alternative in vitro (cell cultures) and in vivo (Caenorhabditis elegans, hen’s egg test) approaches for detailed investigation of the impact of commonly used rosemary, citrus and eucalyptus essential oil on acute, developmental and reproductive toxicity as well as on mucous membrane irritation. In general, all EOs under study exhibited a comparable impact on measured parameters, with a slightly increased toxic potential of rosemary oil. In vitro cell culture results indicated a concentration-dependent decrease of cell viability for all EOs, with mean IC₅₀ values ranging from 0.08 to 0.17% [v/v]. Similar results were obtained for the C. elegans model when using a sensitized bus-5 mutant strain, with a mean LC₅₀ value of 0.42% [v/v]. In wild-type nematodes, approximately tenfold higher LC₅₀ values were detected. C. elegans development and reproduction was already significantly inhibited at concentrations of 0.5% (wild-type) and 0.1% (bus-5) [v/v] of EO, respectively. Gene expression analysis revealed a significant upregulation of xenobiotic and oxidative stress genes such as cyp-14a3, gst-4, gpx-6 and sod-3. Furthermore, all three EOs under study showed an increased short-time mucous membrane irritation potential, already at 0.5% [v/v] of EO. Finally, GC–MS analysis was performed to quantitate the relative concentration of the most prominent EO compounds. In conclusion, our results demonstrate that EOs can exhibit severe toxic properties, already at low concentrations. Therefore, a detailed toxicological assessment is highly recommended for each EO and single intended application.

In vitro and in vivo amelioration of colitis using targeted delivery system of cyclosporine a in New Zealand rabbits

Necessity to develop the efficient targeted delivery of highly potent immunosuppressant for IBD in order to avoid surgical procedure, led to fabrication and evaluation of its anti-inflammatory potential. Previously formulated cyclosporine A (Cyp A) into enteric coated capsules was further evaluated for its site-specificity in the treatment of TNBS induced colitis. Contact angle measurement studies showed excellent spreadability of the developed formulation over the hydrophilic biological tissue substrate. HET-CAM study demonstrates that the formulation prepared is nonirritant to the highly vascular tissues and hence can be used for the immunological sensitive tissues like inflamed intestine in IBD. Further the developed formulation has been characterized for site specificity to distal parts of intestine by pharmacokinetic studies. The appearance of drug in systemic circulation at approximately 5 hours in New Zealand strain of rabbits confirms drug delivery at distal parts of intestine. Significant reduced levels of TNF-α, IL-6 and IL-10 in drug treated animals signifies inhibition of inflammatory reactions at the TNBS treated site. Simultaneously, the change in body weight of same group of animals was observed for 15 days. Results showed a marginal recovery of body weight in Cyp A treated TNBS induced colitis animals. In conclusion, all in vitro and in vivo results confirm the successful site specific delivery and anti-inflammatory efficacy of developed formulation of Cyp A in TNBS induced colitis in New Zealand rabbits.

Synthesis, Characterization, Self-Assembly, and Irritation Studies of Polyglyceryl-10 Caprylates

1,4-dioxane should be less than or equal to 10 ppm in finished cosmetic products according to the recommendation of the Scientific Committee on Consumer Safety, but it is often generated as a by-product during the manufacturing process of poly(ethylene glycol) (PEG)-based derivatives. In order to avoid the possible risk caused by 1,4-dioxane, it might be a good choice for preparing cosmetic ingredients by using polyglycerin (PG) instead of PEG as a hydrophilic segment. In the present study, polyglyceryl-10 caprylates were synthesized by the esterification reaction between polyglycerin-10 and caprylic acid. FTIR and 1H NMR were utilized to confirm the chemical structures of the obtained polyglyceryl-10 caprylates. Light transmittance was availed to investigate the water solubility of polyglyceryl-10 caprylates. The self-assembly behavior, size, and size distribution of polyglyceryl-10 caprylates were investigated by dynamic light scattering. The makeup cleansing effect was also evaluated by in vitro and in vivo methods. Irritation was evaluated by hen's egg test-chorioallantoic membrane assay (HET-CAM). Results showed that polyglyceryl-10 monocaprylate could self-assemble into nanoparticles in the water at the concentration range of 2.5-10 wt% with a transparent appearance. The diameter of formed nanoparticles was around 100 nm with a narrow particle size distribution around 0.1 at the concentration of 2.5 wt% or 5 wt%. Polyglyceryl-10 monocaprylate exhibited good removal effect against makeup and excellent removal efficacy against pen eyeliner. The irritation of polyglyceryl-10 monocaprylate evaluated by HET-CAM at the concentration of 4 wt% was moderate irritant (irritation score = 8.4), which was lower than that of PEG-6 caprylic/capric glycerides (severe irritant, irritation score = 14.1). Therefore, polyglyceryl-10 monocaprylate might be a promising cosmetic ingredient for transparent makeup removing water.