Photostability of Cosmetic UV Filters on Mammalian Skin Under UV Exposure

Previous studies showed that the common UV filter substances benzophenone‐3 (BP–3), butyl methoxydibenzoylmethane (BM–DBM), octocrylene (OCR), ethylhexyl methoxycinnamate (EHMC), ethylhexyl salicylate (EHS) and ethylhexyl triazone (EHT) were able to react with amino side chains of different proteins in vitro. To transfer the results to mammalian skin conditions, sunscreen products were applied on both prepared fresh porcine skin and glass plates, followed by UV irradiation and the determination of depletion of the respective UV filters. Significantly lower recoveries of the UV filters extracted from skin samples than from glass plates indicated the additional reaction of the UV filters with skin constituents, when proteins will be the most important reactants. Among the products tested, BP‐3 showed the greatest differences in recoveries between glass and skin samples of about 13% and 24% after 2 and 4 h of irradiation, respectively, followed by EHS > BM‐DBM > OCR > EHMC > EHT. The obtained results raise the question, whether the common in vitro evaluations of sunscreens, using inert substrate materials like roughened quartz or polymethyl methacrylate (PMMA) plates are really suitable to fully replace in vivo methods, as they cannot include skin‐typical reactions.     

Penetration Study of Formulated Nanosized Titanium Dioxide in Models of Damaged and Sun‐Irradiated Skins

Inorganic ultraviolet filters such as titanium dioxide (TiO₂), safe to use on healthy skin, are often applied on compromised and irradiated skin. The aim of this study was to evaluate in vitro the cutaneous penetration of TiO₂ nanoparticles (≥ 20 nm primary size), included in a sunscreen, in intact, damaged, irradiated, and damaged/irradiated pigskin. Cutaneous penetration and localization of TiO₂ after a 24‐h sunscreen application were investigated quantitatively using inductively coupled plasma‐mass spectrometry, and qualitatively using transmission electron microscopy (TEM). Elemental identity of the nanoparticles was evaluated by TEM‐coupled Energy Dispersive X‐ray analysis (TEM‐EDX). In intact and damaged/irradiated skins, 102.35 ± 4.20% and 102.84 ± 5.67% of the titanium deposited, respectively, were found at the surface and stratum corneum (SC), whereas only 0.19 ± 0.15% and 0.39 ± 0.39% were found in the viable epidermis and dermis and no titanium was detected in the receptor fluid. TEM‐EDX analysis confirmed the presence of titanium in the aggregates formed by TiO₂ at the SC surface, as already characterized in the sunscreen formulation. TiO₂ nanoparticles included in a sunscreen thus remain in the uppermost layers of the SC, whether in intact skin or in compromised and/or skin exposed to simulated solar radiation.     

Comparison of release and penetration of tacrolimus ointment reference and trial formulation after dermal application to pigs by liquid chromatography–electrospray ionization tandem mass spectrometry

To investigate the consistency and bioequivalence of tacrolimus ointment reference and trial formulation, the tacrolimus concentrations in blood and skin were determined by HPLC‐ESI‐MS/MS following topical application of two kinds of ointment in porcine skin in a parallel, cross‐over trial. The plasma protein of blood was precipitated by acetonitrile and the tacrolimus in skin was extracted by acetonitrile before HPLC‐ESI‐MS/MS analysis. The internal calibration method (diazepam was the internal standard) was used for quantification analysis (R² > 0.9999), with linear range from 0.05 to 5 ng/mL for blood samples and from 1 to 200 ng/mL for skin samples. The limits of detection for the porcine blood and skin were 0.005 and 0.5 ng/mL, respectively. The average recoveries for the porcine blood and skin spiked at three levels were 97.56–109.53 and 96.48–103.57%, respectively. The precision expressed in RSDs was from 3.43 to 10.83% for porcine blood and from 3.10 to 8.69% for porcine skin. For the same pig, the tacrolimus concentrations and variation with time of the two kinds of ointment in porcine skin were similar, although variation occurred with different individuals. These results showed that the release and penetration of tacrolimus from the reference and trial formulation are similar. Copyright © 2013 John Wiley & Sons, Ltd.     

Celecoxib determination in different layers of skin by a newly developed and validated HPLC‐UV method

A simple, rapid and sensitive analytical procedure for the measurement of celecoxib (CXB) levels in skin samples after in vitro penetration studies was developed and validated. In vitro permeability studies in porcine skin were performed for quantification of CXB at different layers of skin, the stratum corneum (SC) and epidermis plus dermis (EP + D) as well as in the acceptor solution (AS) to assess CXB permeation through skin. CXB was quantified by HPLC using a C₁₈ column and UV detection at 251 nm. The mobile phase was methanol–water 72:28 (v/v) and the flow‐rate was 0.8 mL/min. The CXB retention time was 5 min. The assay was linear for CBX in the concentration range of 0.1–3.0 μg/mL in the AS (drug permeated through skin) and 5.0–50.0 μg/mL for drug retained in SC and [EP + D] in vitro. The linear correlation coefficients for the different calibration curves were equal or greater than 0.99. Intra‐ and inter‐assay variabilities were below 8.0%. Extraction of CXB from skin samples showed recoveries higher than 95.0% after 15 min of ultrasonic sound and centrifugation at 2500 rpm for 3 min. The method was considered appropriate for the assay of CXB in skin samples, after in vitro cutaneous penetration studies. Copyright © 2011 John Wiley & Sons, Ltd.     

Materials Science Challenges in Skin UV Protection: A Review

UV radiation is one of the critical environmental stress factors for human skin, which can trigger various problems such as pruritus, burning, erythema, premature skin aging and skin cancer. Hence, UV protection has become an indispensable daily routine and the use of topical sunscreen products is rapidly increasing. However, there are emerging concerns over the efficiency and safety of existing chemical and physical UV filters used in consumer products. Furthermore, there is no universally approved method for assessing sun protection efficiency regardless of the immediate end user need to develop safer sunscreen products that afford broad-spectrum photoprotection. It is evident that the current organic and inorganic UV filters have significant unfavorable impacts on human, environmental, and marine safety. Therefore, effective alternative UV filters should be established. This article comprehensively reviews the properties, safety, health and ecological concerns of various UV filters including TiO₂ and ZnO nanoparticles as well as the limitations of the testing protocols and guidelines provided by major regulatory bodies. The photoreactivity of UV filters used in sunscreen remains a major challenge, and it is crucial to develop new sunscreen ingredients, which not only protect the consumer, but also the environment.     

A reversed-phase ion-interaction chromatographic method for in-vitro estimation of the percutaneous absorption of water-soluble UV filters

An analytical method based on ion-interaction chromatography with UV detection for simultaneous in-vitro estimation of the percutaneous absorption of the most used water-soluble UV filters in sunscreen cosmetics is proposed. These UV filters were phenylbenzimidazole sulfonic acid, disodium phenyl dibenzimidazole tetrasulfonate, benzophenone-4, and terephthalylidene dicamphor sulfonic acid. The methodology is based on applying the sunscreen containing the target UV filters to human epidermis in a diffusion cell. Analytes are determined in the receptor solution. To ensure skin integrity, screening of the cells was carried out by analytical determination of a marker. Analytical variables such as percentage ethanol, concentration of ion-pairing agent, pH of the mobile phase, and temperature were studied in order to achieve high resolution of the chromatographic peaks in the lowest possible time of analysis. The conditions selected consisted of a mobile phase composed of 35:65 (v/v) ethanol–ammonium acetate buffer solution (pH 4, containing 50 mmol L⁻¹ tetra-n-butylammonium bromide). The chromatographic determination was carried out with the analytical column at 50 °C. UV detection was carried out at the maximum absorption wavelength for each analyte. The limit of detection (3s _y/x /b) ranged from 16 to 65 ng mL⁻¹, depending on the analyte.     

The Photostabilizing Effect of Grape Seed Extract on Three Common Sunscreen Absorbers

The photostabilizing ability of grape seed extract on three common sunscreen absorbers, 2‐ethylhexyl‐p‐methoxycinnamate (EHMC), benzophenone‐3 (BP3) and tert‐butylmethoxy dibenzoylmethane (BMDBM), was investigated. Samples were exposed to simulated solar radiation and monitored by spectrophotometric and chromatographic methods. The chemical composition of the grape seed extract was determined by GC‐MS and HPLC‐MS, and the major secondary metabolites were found to be epicatechin and catechin. Exposure of the extract to UV radiation increased the UV absorption capacity of the extract. All sunscreens showed an improved photostability in the extract. The inherent photo‐instability of BMDBM when exposed to UV radiation was almost eliminated in the presence of grape seed extract. A mixture of all three sunscreens in the extract showed very high photostability and a red shift covering the entire UVB and UVA regions, thereby improving the broad‐spectrum protection. The incorporation of grape seed extract in sunscreen and other cosmetic formulations for topical application boosts photoprotection by stabilizing the UV filters and enhancing broad‐spectrum coverage. This in turn helps in reducing the amounts of absorbers and other additives incorporated in a sunscreen product and consequently lowers the risk of an unprecedented buildup of photoproducts whose toxicities are currently unknown.     

A mini-review on limitations associated with UV filters

Ultraviolet light from the sun can produce long-term skin damage and cancer. The use of sunscreen products containing one or more UV filters is encouraged by health professionals for preventing the damaging effects resulting from sun exposure. However, recently there have been increasing concerns about the use of sunscreens and their safety for both humans and the environment. The sunscreen manufacturers should take the initiative in testing of the products for possible short-term skin toxicity and long-term health effects that might occur due to the absorption of UV filters through the skin. Published studies have shed light on this topic by investigating the harmful effects of UV filters such as oxybenzone on the hormone system of aquatic animals and humans. Currently, in vitro and in vivo animal models are being used to determine the mechanistic and cellular effects these products produce. With growing awareness of adverse effects posed by UV filters on the environment and exposed organisms, several jurisdictions are prohibiting their use in sunscreens. To our knowledge, very few reviews summarized the potential toxicities associated with UV filters. Therefore, the current reported findings are rather controversial due to the lack of nonclinical safety assessment data to determine the clinical significance of such exposure.     

Simple Extraction and HPLC Determination of UV-A and UV-B Filters in Sunscreen Products

The determination of 11 organic UV filters, worldwide authorised in sunscreen formulations, was performed by HPLC with UV spectrophotometric detection. The filters determined were: phenylbenzimidazole sulfonic acid, benzophenone-4, benzophenone-3, 4-methylbenzylidene camphor, ethylhexyl methoxycinnamate, octocrylene, methylene bis-benzotriazolyl tetramethylbutyl phenol, butyl methoxydibenzoylmethane, bis-ethylhexyloxyphenol methoxyphenyltriazine, ethylhexyl triazone, and diethylamino hydroxybenzoyl hexyl benzoate. Three analytical methods were developed which were based on an ultrasonic extraction of the sample in methanol/1% aqueous acetic acid (70:30, v/v) or dimethylacetamide/propan-2-ol (1:1, v/v) in dependence of the water or fat-solubility of the filter, followed by HPLC separation and quantitation. HPLC was carried out using three different columns and eluting conditions. Standard calibration curves were linear for all the analytes over the concentration range 0.5–100 μg mL^?1. UV measurements were carried out at 280, 300, 310 or 360 nm with the aid of a diode array detector in dependence on the maximum absorption of each filter. Quantitative recoveries were obtained for all sunscreen compounds determined in homemade formulations. The proposed analytical procedure has been successfully applied for the analysis of commercial samples in order to check the presence of UV filters and to determine their concentration.     

Development and validation of HPLC method for imiquimod determination in skin penetration studies

A simple, rapid and sensitive analytical procedure for the measurement of imiquimod in skin samples after in vitro penetration studies has been developed and validated. In vitro penetration studies were carried out in Franz diffusion cells with porcine skin. Tape stripping technique was used to separate the stratum corneum (SC) from the viable epidermis and dermis. Imiquimod was extracted from skin samples using a 7:3 (v/v) methanol:acetate buffer (100 mM, pH 4.0) solution and ultrasonication. Imiquimod was analyzed by HPLC using C(8) column and UV detection at 242 nm. The mobile phase used was acetonitrile:acetate buffer (pH 4.0, 100 mM):diethylamine (30:69.85:0.15, v/v) with flow rate 1 mL/min. Imiquimod eluted at 4.1 min and the running time was limited to 6.0 min. The procedure was linear across the following concentration ranges: 100-2500 ng/mL for both SC and tape-stripped skin and 20-800 ng/mL for receptor solution. Intra-day and inter-day accuracy and precision values were lower than 20% at the limit of quantitation. The recovery values ranged from 80 to 100%. The method is adequate to assay imiquimod from skin samples, enabling the determination of the cutaneous penetration profile of imiquimod by in vitro studies.     

An advanced automation platform coupled with mass spectrometry for investigating in vitro human skin permeation of UV filters and excipients in sunscreen products

Rationale

Systemic absorption of UV-filtering chemicals following topical application of sunscreens may present a safety concern. The Food and Drug Administration (FDA) had recommended an in vitro skin permeation test (IVPT) to evaluate the potential of this safety risk for the evaluation of sunscreens prior to clinical studies. Therefore, a sensitive and robust bioanalytical method(s) were required for IVPT studies of different topical sunscreen products.

Methods

An analytical procedure to quantitate sunscreen UV-filtering components and excipients in IVPT samples including avobenzone, octocrylene, oxybenzone, ecamsule, methylparaben and propylparaben was developed employing a RapidFire 360 robotic sample delivery system coupled with a triple quadrupole mass spectrometer. The analytical procedure was developed and validated according to the requirements of the FDA Bioanalytical Method Validation Guidance for Industry (2018).

Results

The analytical method provided a turnaround time of 12 seconds per sample and was determined to be accurate, precise, specific, and linear over the corresponding analytical ranges. The validated method was successfully applied for two IVPT studies for evaluating the skin permeation potential of UV-filtering chemicals and assisting with the selection of the sunscreen products for the clinical study conducted by the FDA.

Conclusions

This work highlights the first analytical procedure that has applied a non-chromatographic-MS/MS automation platform to an in vitro biopharmaceutics study. The analytical platform simultaneously quantitated four UV filters and two excipients in complex media to evaluate their permeation in IVPT studies. The sample throughput and analytical performance of advanced automation platforms indicate their analytical procedure has the potential to significantly advance the efficiency of IVPT studies to evaluate permeation of a wide variety of UV chemical filters and excipients for topical OTC sunscreen products.

     

Cosmetic Formulations with Melaleuca alternifolia Essential Oil for the Improvement of Photoaged Skin: A Double-Blind,Randomized, Placebo-Controlled Clinical Study

This aim of this study was to evaluate the penetration depth, antioxidant capacity and the clinical efficacy of Melaleuca alternifolia pure essential oil and in a nanoemulsion to prevent skin photoaging. For this, 2% of pure essential oil or 2% of this essential oil in a nanoemulsion were vehiculated in a formulation. The skin penetration was evaluated using confocal Raman microspectroscopy. The radical protection factor was evaluated using electron paramagnetic resonance spectroscopy. For a clinical study, 40 male participants, aged 18–28 years, were enrolled, being divided into three groups: vehicle formulation, M. alternifolia pure essential oil and M. alternifolia Nanoemulsion. All the participants also received a sunscreen SPF 50 to use during the day. Before and after 90 days of study, skin hydrolipidics and morphological characteristics were performed by skin imaging and biophysical techniques. The nanoemulsion presented a lower antioxidant capacity and a higher penetration through the stratum corneum, reaching the viable epidermis, improving the stratum granulosum morphology. The groups presented an increase in the papillary depth, improving in the dermis echogenicity and the collagen fibers. Melaleuca alternifolia essential provides the potential to improve photoaged skin, being the application of nanoemulsion able to reach deeper skin layers.     

Photostabilization Effect of Quercetin on the UV Filter Combination,Butyl Methoxydibenzoylmethane–Octyl Methoxycinnamate

The aim of the study was to investigate the effect of the natural antioxidant quercetin on the photostability of the most widely used combination of UVA (320–400 nm) and UVB (290–320 nm) filters, respectively butyl methoxydibenzoylmethane (BMDBM) and octyl methoxycinnamate (OMC). In order to reproduce the conditions prevalent in commercial sunscreen products, the stabilizing efficacy of quercetin was evaluated in model creams containing BMDBM (3%, wt/wt) together with OMC (4%, wt/wt) and exposed to a solar simulator at an irradiance corresponding to natural sunlight. Quercetin was found to enhance the photostability of the two UV filters in a concentration-dependent way. Addition of quercetin to the sunscreen formulation significantly reduced the photodegradation of BMDBM and OMC from 40.3 ± 2.4 to 27.7 ± 2.6% and from 51.3 ± 2.1 to 42.2 ± 2.0%, respectively. Moreover, comparative photodegradation studies demonstrated that quercetin was much more effective and at a lower concentration than commonly used stabilizer (octocrylene) and antioxidants (vitamin E, butylated hydroxyanisole). In vitro determination of the UVB and UVA protection parameters showed that the quercetin-based formulation fulfilled the official requirements on sunscreen products. Because of its photostabilizing and multiple antioxidant properties, quercetin represents a useful additive for the formulation of effective broad-spectrum sunscreens containing BMDBM and OMC.     

Irradiation of Skin and Contrasting Effects on Absorption of Hydrophilic and Lipophilic Compounds

Increasing legal requirements for risk assessment and efficacy testing in the dermo-cosmetic field have led to the development of alternative test methods. In this study, the porcine skin model was chosen to test the effect of irradiation on the penetration habits of UV filters and caffeine. For decades, the pig has been recognized as an experimental animal in biomedical research thanks to its morphological and physiological similarities to humans. In this study, we wanted to investigate the effect of UV irradiation on the absorption of octocrylene (OC) and benzophenone-3 (B3) sunscreens used under those circumstances and a model hydrophilic molecule, caffeine (Caf). These particular compounds were chosen due to their different lipophilic profiles. The percutaneous penetration of the two UV filters and Caf was studied after two simulated solar radiation doses of 61.4 kJ m⁻². After irradiation simulation, the total absorbed dose was increased for OC while for B3 and Caf it was lower. Thus, modifications in percutaneous absorption have been observed, and it appears that UV could play a crucial role in this process. Moreover, it has been observed that the lipophilic profile of the studied compounds affects percutaneous penetration when irradiated.     

A simple and rapid method to assess butenafine hydrochloride in skin samples and a comparative cutaneous retention study of two marketed formulations

A new method for the quantification of butenafine hydrochloride (BTF) present in the main skin layers was validated and a study conducted with the aim of analyzing the penetration and/or the permeation of the drug. The quantification was performed by liquid chromatography. To evaluate the specificity of the method, the influence of the components of the skin was analyzed, as well as the skin in contact with the excipient ingredients. Linearity was assessed with concentrations in the range of 0.1–10 μg/mL (r ² = 0.9999) and ANOVA showed non‐significant linear deviation (p > 0.05). Adequate results were obtained for repeatability, intra‐day precision and accuracy. The obtained values for the limit of quantification and the limit of detection were 68.4 and 17.7 ng/mL, respectively. Also, a comparative study of BTF cutaneous penetration through porcine skin was performed applying two different formulations: Tefin, present in the Brazilian market, and Lotrimin Ultra^®, available in the American market. No statistical difference was found in the skin (epidermis plus dermis) and in the epidermis (p > 0.05), although in the dermis the difference was significant (p < 0.05). During the experimental period (8 h), no drug permeation from either formulation was detected in the receptor fluid. Copyright © 2011 John Wiley & Sons, Ltd.     

Evaluation of Photoprotective Potential and Percutaneous Penetration by Photoacoustic Spectroscopy of the Schinus terebinthifolius Raddi Extract

Schinus terebinthifolius is a plant rich in phenolic compounds, which have antioxidant properties and can provide new opportunities for treatment and prevention of diseases mediated by ultraviolet radiation like photoaging and skin cancer. The aim of this study was to evaluate the photoprotective potential and ex vivo percutaneous penetration of the crude extract of Schinus terebinthifolius leaves. The extract was tested for antioxidant activity using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) method and β‐carotene bleaching test. The sun protection factor was also evaluated. The ex vivo skin permeation of the emulsion and gel formulations were assayed. Fractionation of the extract resulted in gallic acid, ethyl gallate and a mixture of flavonoids, suggesting derivatives of quercetin and myricetin. The phenolic content of the extract was 384.64 ± 2.60 mg GAE g^?1 extract. The antioxidant activity was superior to butylated hydroxytoluene, in DPPH method, and ascorbic acid and rutin, in β‐carotene bleaching assay. The extract showed UV absorption with photoprotector potential in the UVB region. The photoacoustic spectroscopy measurements confirmed absorption in the UV region and topical application of the formulations caused no histological changes in the rats' skin. These results suggest that the crude extract of Schinus terebinthifolius leaves may be a promising natural sunscreen product.     

Daily Variation of UV‐induced Erythema and the Action of Solar Filters

UV rays may cause several degrees of skin damage, which makes sunscreen research necessary. In addition, skin sensitivity shows daily variations, which can interfere in the detection of the efficacy of the filters. Here, we studied the UV‐induced erythema in hairless rats at two times of the day (light and darkness) using a colorimeter method. The effect of an emulsion with solar filters with or without melatonin was also assayed. Results indicate that the value of a* (from CIELAB color space values L* a* b) was the most useful variable to evaluate the erythema. However, at the UV intensity used, erythema was only detected when irradiation was carried out during the activity phase of the animal, enabling the detection of the protective action of the sunscreen at this time. Thus, daily variations in skin sensitivity have been demonstrated and should be taken into account in dermatological research.     

Photoprotective effects of methoxycinnamidopropyl polysilsesquioxane

A new sunscreen ingredient, methoxycinnamidopropyl polysilsesquioxane (MCP-PSQ), which contains an UV-absorbing p-methoxycinnamoyl group, has been developed synthetically and evaluated using in vitro and in vivo approaches. Previous studies revealed that MCP-PSQ has a raising or boosting effect on the sun protection factor (SPF) of other sunscreen agents. In this study, we demonstrated that MCP-PSQ, an organic/inorganic hybrid compound, has photoprotective effects for human fibroblasts, and for hairless mouse and human skin. MCP-PSQ increases cell viability and suppresses the expression of p53 protein in fibroblasts after UV exposure. In addition, the numbers of sunburn cells and mast cells are reduced by topical application of MCP-PSQ on hairless mouse skin after UV irradiation. A 10% MCP-PSQ cream has higher and similar effects on SPF values for human skin compared to 5% titanium dioxide (TiO(2)) and 5% ethylhexyl methoxycinnamate (EHMC), respectively. The SPF value obtained using the MCP-PSQ cream did not drop after UV irradiation of the cream itself. However, higher dose of UV irradiation is required to guarantee the stability or photostability of the formulation. Further, there were no side effects such as erythema, edema, itch or tingling, suggesting that MCP-PSQ is a good sunscreen agent.     

Inclusion Complexation of the Sunscreen 2-Hydroxy-4-Methoxy Benzophenone (Oxybenzone) with Hydroxypropyl-β-Cyclodextrin: Effect on Membrane Diffusion

It is desirable to minimize skin penetration of some drugs, such as sunscreens and insect repellents. Available in vivo and in vitro data suggest appreciable absorption of some sunscreen agents. The purpose of this study was to investigate the effect of hydroxypropyl--cyclodextrin (HPCD) on the release and permeation of the sunscreen agent 2-hydroxy-4-methoxy benzophenone (oxybenzone). The interaction between oxybenzone and HPCD was studied in water by phase solubility analysis. The inclusion complex was characterized by thermal analysis and nuclear magnetic resonance spectroscopy. UV transmittance and percent UVA transmittance, as a preliminary measure of sun protection factor (SPF), were determined. In vitro permeation experiments were conducted in Franz-type diffusion cells at 37 °C, using the model membrane poly(dimethyl siloxane) (PDMS) and 4% bovine serum albumin in phosphate buffer solution (pH 7.4) as the receptor phase. HPCD caused a marked increase in the aqueous solubility of oxybenzone. Data from the phase solubility experiment indicated the formation of 1:1 oxybenzone-cyclodextrin complex. UV transmittance studies indicated that the presence of HPCD did not suppress the UV absorbing properties of oxybenzone. The release and membrane permeation of oxybenzone was significantly reduced in the presence of equimolar, 2 times molar and 1, 2 and 4% of HPCD. It is concluded that HPCD can reduce the release/membrane diffusion of oxybenzone whilst retaining its efficacy as a sunscreen agent. This formulation strategy may be useful in controlling skin penetration of topically applied sunscreens and other chemicals.     

Solution Thermodynamics of Ethylhexyl Triazone in Some Ethanol + Ethyl Acetate Mixtures

Ethylhexyl triazone (EHT) is a sunscreen agent that is widely used in skin care product formulations, whose physicochemical properties have not been previously studied in detail. For this reason, solubility data were measured for EHT in ethanol (EtOH) + ethyl acetate (AcOEt) mixtures at five temperatures. By using the van’t Hoff and Gibbs equations, the thermodynamic functions: Gibbs energy, enthalpy, and entropy of solution, and of mixing, were evaluated from these solubilities. The solubility is greatest in mixtures with 0.10 and 0.20 mass fraction EtOH, but decrease as the EtOH mass fraction increases in the solvent mixtures. By means of an enthalpy-entropy compensation analysis, a nonlinear DH_soln⁰\Delta H_{\mathrm{soln}}^{0} versus DG_soln⁰\Delta G_{\mathrm{soln}}^{0} compensation plot was obtained having both negative and positive slopes as the solvent composition was varied. Accordingly to these results, it follows that the driving function for solubility of EHT is the entropy for solutions rich in EtOH or AcOEt, whereas in mixtures of medium composition, the driving function is the enthalpy.