Evaluation of eye irritation potential of experimental cosmetic formulations containing glycolic acid, salicylic acid and ethanol using the Bovine Corneal Opacity and Permeability Assay.

OBJECTIVE: Prototype cosmetic formulations containing short-chain acids and alcohols intended to be applied in the proximity of the eyes are sometimes evaluated for ocular irritation potential using the validated Bovine Corneal Opacity and Permeability Assay (OECD TG 437). We evaluated the eye irritation potential of nine experimental cosmetic formulations designed and prepared by Avon Global Reserach and Development to differ only in the concentrations of Ethanol, Glycolic Acid and Salicylic Acid. METHODS: We analysed the data generated using the BCOP assay. The opacity and permeability values obtained following the exposure of bovine corneas to experimental cosmetic formulations were combined into a single In Vitro Irritancy Score used to rank eye irritation potential. Histopathological examination of treated corneas was used to provide additional information about the depth and degree of the injury and to support the prediction of eye irritation potential of each experimental cosmetic formulation. RESULTS: The In Vitro Irritancy Scores and histopathological analysis showed that experimental formulations containing only Ethanol, Glycolic Acid, or Salicylic Acid alone had, at most, a mild ocular irritation potential. The experimental formulations containing both Ethanol and Glycolic Acid had a mild ocular irritation potential, while the experimental formulations containing both Ethanol and Salicylic Acid had a moderate ocular irritation potential. Severe ocular irritation potential was induced by an experimental formulation containing a combination of Glycolic Acid and Salicylic Acid and it was further accentuated by the addition of Ethanol to the formulation. Our data indicate a possible synergistic effect on eye irritation potential of Ethanol, Glycolic Acid and Salicylic Acid in at least some experimental cosmetic formulations. Further, our results provide insight on an apparent concentration-dependent ocular irritation potential effect of combinations of Glycolic Acid, Salicylic Acid and Ethanol in at least one experimental cosmetic formulation. CONCLUSIONS: The results presented herein emphasise the need to consider in vitro testing of prototype cosmetic formulations containing combinations of Ethanol, Glycolic Acid and Salicylic Acid rather than relying on any predicted additive effect on ocular irritation based solely on previously generated results of similar formulations containing Ethanol, Glycolic Acid or Salicylic Acid alone. Further work is required to understand the significance of these observations and to elucidate the mechanisms responsible for the apparent synergistic effects of Glycolic Acid, Salicylic Acid and Ethanol and eye irritation potential suggested by our results.

Development of a Probability-Based In Vitro Eye Irritation Screening Platform.

Traditional eye irritation assessments, which rely on animal models or ex vivo tissues, face limitations due to ethical concerns, costs, and low throughput. Although numerous in vitro tests have been developed, none have successfully reconciled the need for high experimental throughput with the accurate prediction of irritation potential, attributable to the complexity of irritation mechanisms. Simple cell models, while suitable for high-throughput screening, offer limited mechanistic insights, contrasting with more physiologically relevant but less scalable complex organotypic corneal tissue constructs. This study presents a novel strategy to enhance the predictive accuracy of screening-compatible simple cell models in eye irritation testing. Our method combines the results of two in vitro assays-cell apoptosis and nociceptor (TRPV1) activation-using micropatterned chips to partition human corneal epithelial cells into numerous discrete small populations. Following exposure to test compounds, we measure apoptosis and nociceptor activation responses. The large datasets collected from the cell micropatterns facilitate binarization and statistical fitting to calculate a mathematical probability, which assesses the compound's potential to cause eye irritation. This method potentially enables the amalgamation of multiple mechanistic readouts into a singular index, providing a more accurate and reliable prediction of eye irritation potential in a format amenable to high-throughput screening.

Silk Fibroin Formed Bioadhesive Ophthalmic Gel for Dry Eye Syndrome Treatment.

PURPOSE: Dry eye syndrome (DES), arising from various etiologic factors, leads to tear film instability and ocular surface damage. Given its anti-inflammatory effects, cyclosporine A (CsA) has been widely used as a short-term treatment option for DES. However, poor bioavailability and solubility of CsA in aqueous phase make the development of a cyclosporine A-based eye drop for ocular topical application a huge challenge. METHODS: In this study, a novel strategy for preparing cyclosporine A-loaded silk fibroin nanoemulsion gel (CsA NBGs) was proposed to address these barriers. Additionally, the rheological properties, ocular irritation potential, tear elimination kinetics, and pharmacodynamics based on a rabbit dry eye model were investigated for the prepared CsA NBGs. Furthermore, the transcorneal mechanism across the ocular barrier was also investigated. RESULTS: The pharmacodynamics and pharmacokinetics of CsA NBGs exhibited superior performance compared to cyclosporine eye drops, leading to a significant enhancement in the bioavailability of CsA NBGs. Furthermore, our investigation into the transcorneal mechanism of CsA NBGs revealed their ability to be absorbed by corneal epithelial cells via the paracellular pathway. CONCLUSION: The CsA NBG formulation exhibits promising potential for intraocular drug delivery, enabling safe, effective, and controlled administration of hydrophobic drugs into the eye. Moreover, it enhances drug retention within the ocular tissues and improves systemic bioavailability, thereby demonstrating significant clinical translational prospects.

A Novel Ex Vivo Blinking Method for Comparing the Corneal Residence Time of New Shampoo Formulations.

In the cosmetics sector, many products such as shampoos have a probability of accidental ocular exposure during their routine use. One very specific safety parameter is the residence time of the substance on the corneal surface, as prolonged exposure may cause injury. In this study, we developed a system that simulates corneal exposure to blinking and tear flow, for comparing the corneal clearance times of viscous detergent formulations. The Ex Vivo Eye Irritation Test (EVEIT), which uses corneal explants from discarded rabbit eyes from an abattoir, was used as the basis for the new system. To simulate blinking, we developed a silicone wiping membrane to regularly move across the corneal surface, under conditions of constant addition and aspiration of fluid, to mimic tear flow. Six shampoo formulations were tested and were shown to differ widely in their corneal clearance time. Three groups could be identified according to the observed clearance times (fast, intermediate and slow); the reference shampoo had the shortest clearance time of all tested formulations. With this new system, it is now possible to investigate an important physicochemical parameter, i.e. corneal clearance time, for the consideration of ocular safety during the development of novel cosmetic formulations.

Advancing ocular safety research: A comprehensive examination of benzocaine acute exposure without animal testing.

Benzocaine is a widely employed local anaesthetic; however, there is a notable dearth of preclinical and clinical evidence regarding its safety in ophthalmological products. To address this, a comprehensive strategy incorporating in silico and in vitro methodologies was proposed for assessing benzocaine's ocular toxicity without animal testing. To collect the in silico evidence, the QSAR Toolbox (v4.5) was used. A single exposure to two benzocaine concentrations (2% and 20%) was evaluated by in vitro methods. Hen's Egg Chorioallantoic Membrane Test (HET-CAM) was performed to evaluate the effects on the conjunctiva. To study corneal integrity, Short Time Exposure test (STE) and Bovine Corneal Opacity and Permeability (BCOP) assay, followed by histopathological analysis, were carried out. Results from both in silico and in vitro methodologies categorize benzocaine as non-irritating. The histopathological analysis further affirms the safety of using benzocaine in eye drops, as no alterations were observed in evaluated corneal strata. This research proposes a useful combined strategy to provide evidence on the safety of local anaesthetics and particularly show that 2% and 20% benzocaine solutions do not induce eye irritation or corneal damage, supporting the potential use of benzocaine in the development of ophthalmic anesthetic products.

Retrospective evaluation of the eye irritation potential of agrochemical formulations.

Multiple in vitro eye irritation methods have been developed and adopted as OECD health effects test guidelines. However, for predicting the ocular irritation/damage potential of agrochemical formulations there is an applicability domain knowledge gap for most of the methods. To overcome this gap, a retrospective evaluation of 192 agrochemical formulations with in vivo (OECD TG 405) and in vitro (OECD TG 437, 438, and/or 492) data was conducted to determine if the in vitro methods could accurately assign United Nations Globally Harmonized System for Classification and Labelling of Chemicals (GHS) eye irritation hazard classifications. In addition, for each formulation the eye irritation classification was derived from the classification of the contained hazardous ingredients and their respective concentration in the product using the GHS concentration threshold (CT) approach. The results herein suggest that the three in vitro methods and the GHS CT approach were highly predictive of formulations that would not require GHS classification for eye irritation. Given most agrochemical formulations fall into this category, methods that accurately identify non-classified agrochemical formulations could significantly reduce the use of animals for this endpoint.

Defined approaches to classify agrochemical formulations into EPA hazard categories developed using EpiOcularTM reconstructed human corneal epithelium and bovine corneal opacity and permeability assays.

Many sectors have seen complete replacement of the in vivo rabbit eye test with reproducible and relevant in vitro and ex vivo methods to assess the eye corrosion/irritation potential of chemicals. However, the in vivo rabbit eye test remains the standard test used for agrochemical formulations in some countries. Therefore, two defined approaches (DAs) for assessing conventional agrochemical formulations were developed, using the EpiOcularTM Eye Irritation Test (EIT) [Organisation for Economic Co-operation and Development (OECD) test guideline (TG) 492] and the Bovine Corneal Opacity and Permeability (OECD TG 437; BCOP) test with histopathology. Presented here are the results from testing 29 agrochemical formulations, which were evaluated against the United States Environmental Protection Agency's (EPA) pesticide classification system, and assessed using orthogonal validation, rather than direct concordance analysis with the historical in vivo rabbit eye data. Scientific confidence was established by evaluating the methods and testing results using an established framework that considers fitness for purpose, human biological relevance, technical characterisation, data integrity and transparency, and independent review. The in vitro and ex vivo methods used in the DAs were demonstrated to be as or more fit for purpose, reliable and relevant than the in vivo rabbit eye test. Overall, there is high scientific confidence in the use of these DAs for assessing the eye corrosion/irritation potential of agrochemical formulations.

Semi-Correlations for Building Up a Simulation of Eye Irritation.

The OECD recognizes that data on a compound's ability to treat eye irritation are essential for the assessment of new compounds on the market. In silico models are frequently used to provide information when experimental data are lacking. Semi-correlations, as they are called, can be useful to build up categorical models for eye irritation. Semi-correlations are latent regressions that can be used when the endpoint is expressed by two values: 1 for an active molecule and 0 for an inactive molecule. The regression line is based on the descriptor values which serve to distribute the data into four classes: true positive, true negative, false positive, and false negative. These values are applied to calculate the corresponding statistical criterion for assessing the predictive potential of the categorical model. In our model, the descriptor is the sum of what are termed correlation weights. These are defined by optimization using the Monte Carlo method. The target function of the optimization is related to the determination coefficient and the mean absolute error for the training set. Our model gives results that are better than those previously reported for the same endpoint.

Evaluation of MTT reducers and strongly colored substances in the Short Time Exposure test method for assessing eye irritation potential.

The Short Time Exposure (STE) test evaluates eye irritation potential using a 3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. MTT assays may underpredict results for some substances that directly reduce MTT (i.e., MTT reducers) or interfere with absorbance because of their strong color (i.e., strongly colored substances). Based on previous research, we selected 25 substances as MTT reducers. Of these, 13 were expected to be MTT reducers at 5% dilution (5% MTT reducers) of the STE test condition. These 13 substances were then tested to determine whether the results were interfered from direct MTT reduction. Those 5% MTT reducers that were classified as irritants based on in vivo data were identified as irritants by the STE test. In addition, the low cell viability results at 5% dilution suggested that direct MTT reduction had not occurred. Next, the remaining 5% MTT reducers that were classified as non-irritants based on in vivo data were identified as non-irritants by the STE test. We then examined two strongly colored substances. One was classified as an irritant based on in vivo data and was confirmed as an irritant by the STE test. The other was classified as a non-irritant by the STE test. This was further evaluated using a medium that did not contain MTT; the result indicated that it was a non-irritant correctly. In conclusion, the STE test is useful for evaluating eye irritation potential without the drawback of underprediction for MTT reducers and strongly colored substances.

In Silico Prediction of Eye Irritation Using Hansen Solubility Parameters and Predicted pKa Values.

An in silico method has been developed that permits the binary differentiation between pure liquids causing serious eye damage or eye irritation, and pure liquids with no need for such classification, according to the UN GHS system. The method is based on the finding that the Hansen Solubility Parameters (HSP) of a liquid are collectively important predictors for eye irritation. Thus, by applying a two-tier approach in which in silico-predicted pKa values (firstly) and a trained model based solely on in silico-predicted HSP data (secondly) were used, we have developed, and validated, a fully in silico approach for predicting the outcome of a Draize test (in terms of UN GHS Cat. 1/Cat. 2A/Cat. 2B or UN GHS No Cat.) with high validation set performance (sensitivity = 0.846, specificity = 0.818, balanced accuracy = 0.832) using SMILES only. The method is applicable to pure non-ionic liquids with molecular weight below 500 g/mol, fewer than six hydrogen bond donors (e.g. nitrogen-hydrogen or oxygen-hydrogen bonds) and fewer than eleven hydrogen bond acceptors (e.g. nitrogen or oxygen atoms). Due to its fully in silico characteristics, this method can be applied to pure liquids that are still at the desktop design stage and not yet in production.

Skin and eye irritancy assessment of six lactic acid bacteria strains.

Here we investigate the suitability of in vitro models to assess the skin and eye irritation potential of six microbial strains. Acute skin irritation was tested according to the unmodified and modified OECD test guideline (OECD TG) 439, while acute eye irritation was examined using the OECD TG 491 and 492. The OECD TG 439 guideline, modified to introduce 8-10 µg/mL of streptomycin during the recovery phase and use of test items containing 100% microbial product instead of finished formulae, was found to be suitable for skin irritation evaluation. On the other hand, the OECD TG 491 procedure was the most appropriate for evaluating eye irritation. None of the six microbial strains, namely, Lactiplantibacillus plantarum (IMI 507026, IMI 507027, IMI 507028), Lacticaseibacillus rhamnosus (IMI 507023), and Pediococcus pentosaceus (IMI 507024, IMI 507025), tested in this study caused skin or eye irritation under the study condition.

Preliminary Study on an Alternative Test Method with MCTT HCETM for Ocular Irritation Test of Ophthalmic Medical Devices.

The sustained growth of the market for ophthalmic medical devices has increased the demand for alternatives to animal testing for the evaluation of eye irritation. The International Organization for Standardization has acknowledged the need to develop novel in vitro tests to replace animal testing. Here, we evaluated the applicability of an alternative method based on a human corneal model to test the safety of ophthalmic medical devices. 2-Hydroxyethyl methacrylate (HEMA) and Polymethyl methacrylate (PMMA), which are used to fabricate contact lenses, were used as base materials. These materials were blended with eye irritant and non-irritant chemicals specified in the OECD Test Guideline (TG) 492 and Globally Harmonized System (GHS) classification. Then, three GLP-certified laboratories performed three replicates using the developed method using 3D reconstructed human cornea epithelium, MCTT HCETM. OECD TG 492 describes the procedure used to evaluate the eye hazard potential of the test chemical based on its ability to induce cytotoxicity in a reconstructed human cornea-like epithelium (RhCE) tissue. Results: The within-laboratory reproducibility (WLR) and between-laboratory reproducibility (BLR) were both 100%. When a polar extraction solvent was used, the sensitivity, specificity, and accuracy were all 100% in each laboratory. When a non-polar extraction solvent was used, the sensitivity was 80%, the specificity was 100%, and the accuracy was 90%. The proposed method exhibited excellent reproducibility and predictive capacity within and between laboratories. Therefore, the proposed method using the MCTT HCETM model could be used to evaluate eye irritation caused by ophthalmic medical devices.

Topical Application of Linezolid-Loaded Chitosan Nanoparticles for the Treatment of Eye Infections.

Linezolid (LZ) loaded chitosan-nanoparticles (CSNPs) was developed by the ionic-gelation method using Tripolyphosphate-sodium as a crosslinker for topical application for the treatment of bacterial eye infections. Particles were characterized by Zeta-Sizer (Malvern Nano-series). TEM was used for structural morphology. Encapsulation and drug loading were estimated by measuring the unencapsulated drug. In-vitro drug release in STF (pH 7) was performed through a dialysis membrane. Storage stability of LZ-CSNPs was checked at 25 °C and 40 °C for six months. The antimicrobial potency of NPs was evaluated on different Gram-positive strains. Ocular irritation and pharmacokinetic studies were completed in rabbits. Ex-vivo transcorneal permeation of the drug was determined through the rabbit cornea. Ionic interaction among the oppositely charged functional groups of CS and TPP generated the CSNPs. The weight ratio at 3:1, wt/wt (CS/TPP) with 21.7 mg of LZ produced optimal NPs (213.7 nm with 0.387 of PDI and +23.1 mV of ZP) with 71% and 11.2% encapsulation and drug loading, respectively. Around 76.7% of LZ was released from LZ-AqS within 1 h, while 79.8% of LZ was released from CSNPs at 12 h and 90% at 24 h. The sustained drug release property of CSNPS was evaluated by applying kinetic models. The linearity in the release profile suggested that the release of LZ from CSNPs followed the Higuchi-Matrix model. LZ-CSNPs have shown 1.4 to 1.6-times improved antibacterial activity against the used bacterial strains. The LZ-CSNPs were "minimally-irritating" to rabbit eyes and exhibited 4.4-times increased transcorneal permeation of LZ than from LZ-AqS. Around 3-, 1.2- and 3.1-times improved Tmax, Cmax, and AUC0-24 h, respectively were found for LZ-CSNPs during the ocular pharmacokinetic study. AqS has shown 3.1-times faster clearance of LZ. Conclusively, LZ-CSNPs could offer a better alternative for the prolonged delivery of LZ for the treatment of bacterial infections in the eyes.

Development of a Defined Approach for Eye hazard identification of chemicals having surfactant properties according to the three UN GHS categories.

The purpose of this study was to develop a defined approach (DA) for eye hazard identification according to the three UN GHS categories for surfactants (DASF). The DASF is based on a combination of Reconstructed human Cornea-like Epithelium test methods (OECD TG 492; EpiOcular™ EIT and SkinEthic™ HCE EIT) and the modified Short Time Exposure (STE) test method (0.5% concentration of the test substance after a 5-min exposure). DASF performance was assessed by comparing the prediction results with the historical in vivo data classification and against the criteria established by the OECD expert group on eye/skin. The DASF yielded a balanced accuracy of 80.5% and 90.9% of Cat. 1 (N = 22), 75.0% of Cat. 2 (N = 8), and 75.5% of No Cat. (N = 17) surfactants were correctly predicted. The percentage of mispredictions was below the established maximum values except for in vivo No Cat. surfactants that were over-predicted as Cat. 1 (5.6%, N = 17), with a maximum value set at 5%. The percentage of correct predictions did meet the minimum performance values of 75% Cat. 1, 50% Cat. 2, and 70% No Cat. established by the OECD experts. The DASF has shown to be successful for eye hazard identification of surfactants.

Health safety of parabens evaluated by selected in vitro methods.

Seven selected parabens (4 allowed, 3 banned in cosmetics) were tested in order to confirm and expand historical data on their toxicological properties and safety. The aim was to apply novel in vitro methods, which have been sufficiently technically and scientifically validated for the purposes of toxicological testing of chemicals. The study included several toxicological endpoints such as skin/eye irritation, skin sensitization, endocrine disruption and genotoxicity. The battery of selected methods comprised regulatory accepted EpiDerm™ skin model (OECD TG 439); EpiOcular™ corneal model (OECD TG 492) and scientifically valid test method HET-CAM (DB-ALM Protocol No. 47); in chemico test DPRA (OECD TG 442C); in vitro test LuSens (OECD TG 442D) and in vitro test h-CLAT (OECD TG 442E); Ames MPF™ (Xenometrix) and XenoScreen YES/YAS (Xenometrix). Overall, none of the 4 allowed parabens exhibited skin/eye irritation or genotoxicity. However, all allowed parabens in cosmetics were predicted as samples with potentially sensitizing properties in the LuSens and h-CLAT test methods, but not confirmed by DPRA. Endocrine disruption was recorded only at high concentrations, whereas methyl paraben and ethyl paraben exhibited the lowest activity. This study confirmed the safety of use of the allowed parabens in the highest recommended concentrations in cosmetics or pharmaceuticals.

Tissue Engineered Mini-Cornea Model for Eye Irritation Test.

BACKGROUND: Eye irritation tests with animals have been conducted for a long time. However, the subjective decision to irritation, the anatomic/physiologic difference between species and humans, and ethical issues are crucial problems. Various research groups have paid attention to alternative testing methods. In these senses, we fabricated in vitro mini-cornea models with immortalized human corneal epithelial cells (iHCECs) and keratocytes (iHCKs) and used them for irritation tests. This study hypothesized that our mini-cornea model could present different viability tendencies according to test chemicals with different irritancy levels. METHODS: Cells used in this study were characterized with cornea-specific markers by immunocytochemistry and western blot. To make a three-dimensional hemisphere construct like cornea stroma, we cultured iHCKs under modified culture conditions verified by matrix formation and total collagen content. iHCECs were seeded on the construct and cultured at an air-liquid interface. The model was treated with 2-phenoxyethanol, triton X-100, sodium lauryl sulfate, and benzalkonium chloride. RESULTS: iHCECs and iHCKs presented their specific cell markers. In modifying the culture condition, the group treating ascorbic acid (200 µg/ml) presented an intact cellular matrix and included the highest collagen content; thus, we used this condition to fabricate the mini-cornea model. The model shows hemisphere shape and homogenous cell distributions in histological analysis. We observed different sensitivity tendencies by types of chemicals, and the model's viability significantly decreased when the chemical concentration increased. CONCLUSION: In this study, we performed and observed irritation tests using a tissue-engineered mini-cornea model and considered to apply as an alternative approach for animal tests.

Reliable prediction of sensory irritation threshold values of organic compounds using new models based on linear free energy relationships and GC×GC retention parameters.

The human sensory irritation threshold (SIT) is an important biochemical parameter for the exposure assessment of organic air pollutants. First, we recalibrated the Abraham solvation models (ASMs) for 9 SIT endpoints by curating 720 individual experimental SIT values to find an accurate and parsimonious ASM variant, which exhibited root mean square error (RMSE) = 0.174-0.473 log unit. Second, we report linear free energy relationships - henceforth called partition models (PMs) - which exploit the correlations of 9 SIT endpoints with the linear combinations of partition coefficients for octanol-water and air-water systems showing RMSE = 0.221-0.591 log unit. These PMs can easily be integrated into widely used EPI-Suite™ screening tool. The explanatory and predictive performance of PMs were like parameter-intensive ASMs. Third, we present GC × GC models that are based on the retention times of the nonpolar analytes on the comprehensive two-dimensional gas chromatography (GC × GC), which successfully described the SIT variance (R2=0.959-0.996) and depicted a strong predictive power (RMSE = 0.359-0.660 log unit) for an independent set of nonpolar analytes. Taken together, PMs allow easy SIT screening of organic chemicals compared to ASMs. Unlike ASMs, our GC × GC models can be applied to estimate SIT of complex nonpolar mixtures.

Expansion of the application domain of a macromolecular ocular irritation test (OptiSafe™).

The OptiSafe (OS) test is shelf-stable, macromolecular eye irritation test that does not include any animal ingredient or component ("vegan"). The purpose of this study was to evaluate the test's accuracy for an expanded application domain for both the original and recently updated OS method. This study involved the testing of additional ocular corrosives and previously excluded foaming agents ("surfactants") using both the original and updated OS methods and then combining these data with prior validation data for a total of 147 chemicals. Predictivity was evaluated by a statistical comparison of the OptiSafe predictions with historical in vivo "Draize" rabbit eye data for the same chemicals (from public databases). We report that for the detection of chemicals not requiring classification for eye irritation [Globally Harmonized System of Classification and Labeling of Chemicals (GHS) No Category], the accuracy, specificity, and sensitivity were 92.8%, 79.6%, and 100.0%, respectively, for the updated method; for the detection of chemicals inducing extreme eye damage/corrosion (GHS Category 1), the accuracy, specificity, and sensitivity were 79.4%, 71.8%, and 91.7%, respectively, for the updated method. Results indicate that both the original and updated methods have a high accuracy for the expanded application domain that included ocular corrosives and surfactants.

The eye irritation test and pharmacokinetic study of tacrolimus-loaded cationic nanoemulsion-based in-situ gel in rabbits / 药学实践杂志

Objective To study the eye irritation and the pharmacokinetics of tacrolimus-loaded cationic nanoemulsion-based in-situ gel in rabbits. Methods The eye irritation of tacrolimus-loaded cationic nanoemulsion-based in-situ gel in rabbits was observed by histological cross-sections of external ocular tissues stained with HE. The aqueous humor of rabbit eyes was extracted by corneal puncture and analyzed by HPLC-MS for pharmacokinetic study. Results Tacrolimus-loaded cationic nanoemulsion-based in-situ gel had no significant irritation on rabbit eyes. The pharmacokinetic parameter showed that the AUC of tacrolimus-loaded cationic nanoemulsion-based in-situ gel was (128.34±13.09) ng·h/ml, which was 1.13 times of tacrolimus-loaded cationic nanoemulsion (113.61±12.36) ng·h/ml and 1.88 times of Talymus® (68.25±10.82) ng·h /ml. Conclusion Tacrolimus-loaded cationic nanoemulsion-based in-situ gel had the advantages of low irritation, long retention time and high bioavailability in rabbit eyes. It has a good potential for clinical application.

Prediction of serious eye damage or eye irritation potential of compounds via consensus labelling models and active learning models based on uncertainty strategies.

Serious eye damage and eye irritation have been authenticated to be significant human health issues in various fields such as ophthalmic pharmaceuticals. Due to the shortcomings of traditional animal testing methods, in silico methods have advanced to study eye toxicity. The models for predicting serious eye damage and eye irritation potential of compounds were developed using 2299 and 5214 compounds, respectively. The 40 global single models and 40 local models were developed by combining 5 molecular description methods and 4 machine learning methods. The 40 active learning models were developed by adopting uncertainty-based active learning strategies and taking local models as initial models. The 110 global consensus models based on 40 global single models were developed using a consensus strategy. Active learning models and global consensus models performed high prediction accuracy. The test accuracy of the best serious eye damage model and eye irritation model reached 0.972 and 0.959, respectively. The applicability domains for all models were calculated to verify the rationality of prediction effect. In addition, 8 structural alerts probably causing serious eye damage or eye irritation were sought out. The prediction models and structural alerts contributed to providing hazard identification and assessing chemical safety.