Propylene Glycol Solution Research Articles

Experimental Investigation of the Apparent Thermal Conductivity of Microencapsulated Phase-Change-Material Slurry at the Phase-Transition Temperature.

The article presents the results of detailed studies of the thermal conductivity of the water slurry of microencapsulated PCM (mPCM) and slurry based on water–propylene glycol solutions. The starting product, MICRONAL® 5428 X, which contains about 43% microencapsulated paraffin with a transformation temperature of 28 °C, was mixed with the base liquid to obtain slurries with mass fractions of mPCM of 4.3, 8.6, 12.9, 17.2, 21.5, 25.8, 30.1, 34.4, 38.7, and 43.0%. Detailed measurements were carried out in the temperature range of 10–40 °C. It was found that: (a) an increase in the temperature of the slurry caused an increase in its thermal conductivity, both when PCM was in the form of a solid and a liquid; (b) the thermal conductivity of the mPCM slurry when the PCM was in liquid form was greater than the thermal conductivity of the slurry when the PCM was liquid; (c) during the phase transformation, a significant increase in the thermal conductivity of the slurry was observed, and its peak occurred when the temperature of the slurry reached the temperature declared by the manufacturer at which the phase-transition peak occurs.

Development of transdermal based hydrogel formulations of vinorelbine with an evaluation of their in vitro profiles and activity against melanoma cells and in silico prediction of drug absorption

The primary course of melanoma treatment involves surgery in association with chemotherapy. One potential agent is vinorelbine (VNR). While it displays anti-proliferative activity against melanoma cell lines, it presents a low oral bioavailability and intravenous administration often causes irritation, phlebitis and pain at the injection site. The aim of this study was to develop Pluronic® F-127 (PF-127) hydrogels containing VNR for the transdermal route of administration. Hydrogels composed of either 15% (G15), 20% (G20), 23% (G23) or 25% (G25) PF-127 aqueous solutions were loaded with a VNR propylene glycol solution. Their release and permeation profiles for VNR were evaluated in a Franz diffusion cell. In addition, their rheological behavior, visual aspect during storage and the in silico prediction of VNR absorption using GastroPlus® were evaluated. The G20 and G23 formulations showed similar release and permeation profiles with the G20 demonstrating a higher permeation of VNR at 8h (p < 0.05) and cumulative permeated drug amount of 495.2 ± 46.7 μg/cm2 at 24h. Further, their activity was tested on the melanoma cell lines SK-MEL28 and MV-3 to evaluate cell viability and proliferation. At VNR concentrations of 75 and 100 μg/mL, cell viability of both melanoma cells was lower in the presence of the G20 formulation than G23 after 24h of treatment although the proliferation profiles were similar. When combined with an in silico pharmacokinetic model, the results suggest that the transdermal administration of VNR could be a promising alternative to intravenous administration and that the G20 formulation would be an excellent candidate for the direct application onto melanomas.

Vapor-phase oxidation of propylene glycol-methanol mixture to methyl lactate on CeO2/Al2O3 catalyst

The vapor-phase oxidation of mixtures of propylene glycol with methanol and ethanol to methyl and ethyl lactate, respectively, on supported CeO2/Al2O3 catalyst with 10 wt.% CeO2 content was studied. The steel flow reactor with a fixed catalyst bed (4 cm3) was used. 20 wt.% solution of propylene glycol in alcohol was fed to the reactor inlet by Waters 950 pump at LHSV= 0.5-0.8 h-1. Reaction temperature and pressure were varied in the interval of 190-250 0C and 1.3-1.8 bars respectively. Compressed air was given to the reactor inlet at the molar ratio of propylene glycol/O2 = 1. The reaction products were analyzed using gas chromatography (Agilent 7820A) and 3C NMR (Bruker Avance 400) methods. Studied oxidation of propylene glycol in the presence of methanol describes by total reaction CH3CHOHCH2OH +O2 + СН3OH = CH3CHOHCOOСН3 +2H2O At first, hydroxyacetone is formed that is further oxidized to pyruvic aldehyde, which attaches alcohol to form hemiacetal. Then, hemiacetal of methyl glyoxal rearranges into methyl lactate by Cannizzaro. At 220 0C and load on a catalyst of &lt; 2 mmol PG/gcat/h, the selectivity towards methyl lactate reaches 70 wt.% at 100 % propylene glycol conversion. The main by-products are formed as the result of acetaldehyde transformation. Acetaldehyde could be formed at hydroxyacetone aldol decondensation. In the presence of ethanol, the formation of a significant amount of acetaldehyde and its aldol condensation products as well as the formation of diethoxyethane are observed. Therefore, ethyl lactate selectivity at 100 % propylene glycol conversion does not exceed 45 %. Supported CeO2/SiO2 contact was tested in this oxidation reaction also. However, CeO2/SiO2 provides the low, up to 25%, selectivity towards methyl lactate at full propylene glycol conversion. It was shown that at the same conditions methyl lactate is formed with higher selectivity then ethyl lactate. The high methyl lactate yield up to 70 wt.% could be obtained via vapor-phase oxidation of 20% mixture of propylene glycol with methanol by air oxygen on supported CeO2/Al2O3 catalyst at 210 - 220°С and at time contact of 3-4 seconds.

Determining the Heat of Fusion and Specific Heat of Microencapsulated Phase Change Material Slurry by Thermal Delay Method

This paper details an experimental study that was performed to investigate the specific heat of microencapsulated phase change material (mPCM) slurry and its heat of fusion at the PCM phase change transition temperature. Six samples (mPCM slurry concentrate with the water solution of propylene glycol used as a main base liquid) were prepared. As the concentrate contains 43.0% mPCM, the actual mass fraction amounts to 8.6, 12.9, 17.2, 21.5, 25.8, and 30.1 wt%, respectively. The thermal delay method was used. Samples were cooled from 50 °C to 10 °C. A higher concentration of microcapsules caused a proportional increase in the specific heat of slurry at the main peak melting temperature. The maximum value of the specific heat changed from 9.2 to 33.7 kJ/kg for 8.6 wt%, and 30.1 wt%, respectively. The specific heat of the mPCM slurry is a constant quantity and depends on the concentration of the microcapsules. The specific heat of the slurry (PCM inside microcapsules in a liquid form) decreased from 4.0 to 3.8 kJ/(kgK) for 8.6 wt%, and 30.1 wt% of mPCM, respectively. The specific heat of the slurry (PCM inside microcapsules in a liquid form) was higher than when the PCM in the microcapsules is in the form of a solid and increased from 4.5 to 5.2 kJ/(kgK) for 8.6 wt% and 30.1 wt% of mPCM, respectively.

Viscosity Model for Liquid Mixtures of Propylene Glycol, Glycerol, and Water

The viscosity of liquid mixtures in e-vapor products (EVPs) is key to their performance and is sensitive to mixture composition and temperature. To date, no accurate model exists for the viscosities of said mixtures. Herein, we report an empirical model for the viscosity of liquid mixtures containing propylene glycol (PG), glycerol (GL), and water (W), representative of the mixtures in EVPs. The model captures the interactions between component liquids and makes accurate viscosity predictions for liquid mixtures of PG, GL, and W, as well as such mixtures containing small amounts of menthol, from 20 to 80 °C. The model is calibrated to new experimental data for PG–GL–W ternary mixtures and may be extended to incorporate different or additional liquids or a wider temperature range given additional fitting data. The model should also prove beneficial for food, cosmetic, and pharmaceutical products containing aqueous solutions of PG and GL.

The study of the antimicrobial activity of ointments with the lipophilic extract from Salix viminalis L. Shoots

The increase in the number of purulent-inflammatory diseases and postoperative purulent complications, as well as deterioration of the results of treating purulent surgical infections, including the formation of antibiotic-resistant strains of microorganisms, leads to the search for effective antimicrobial substances. Plant extracts can be used for these purposes.Aim. To expand the range of domestic ointments containing substances of natural origin as active pharmaceutical ingredients (API). To achieve the aim the team of authors has studied the possibility of developing an ointment on a hydrophilic base using the lipophilic extract from Salix viminalis shoots as API and the analysis of its antimicrobial properties.Materials and methods. As the study object the samples of semisolid medicinal forms containing the lipophilic extract from Salix viminalis shoots in the concentration from 1 % to 10 % on a hydrophilic ointment base with Tween-80, propylene glycol (PG) solution and an alloy of polyethylene oxides (PEO) 400 and 1500 were used. As the method of the samples efficiency control the method of diffusion into agar with the growth inhibition zone determination was chosen. Staphylococcus aureus ATCC 25923, Esherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Bacillus subtilis ATCC 6633, Proteus vulgaris ATCC 4636 and Candida albicans ATCC 885-653 strains were used.Results and discussion. The studies conducted have proven the presence of the antimicrobial activity in the samples of ointments on a complex hydrophilic base. A gradual increase in the antimicrobial activity of ointments has been found with an increase in the concentration of the extract from Salix viminalis shoots. The results obtained can be used as the base for further biopharmaceutical research and the aim implementation.Conclusions. As a result of the studies conducted the optimal concentration of the Salix viminalis extract in the ointment composition on the hydrophilic base has been determined. The composition developed exhibits a pronounced antimicrobial activity against strains of Staphylococcus aureus, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Basillus subtilis and Candida albicans. The ointment can be used to treat infectious complications of wounds.

Hydrogels containing soybean isoflavone aglycones-rich fraction-loaded nanoemulsions for wound healing treatment – in vitro and in vivo studies

Soybean isoflavone aglycones have been investigated as potential wound healing compounds for topical application. The aim of this study was to evaluate the wound healing properties of a soybean isoflavone aglycones-rich fraction (IAF) when incorporated into lipid nanoemulsions dispersed in acrylic-acid hydrogels. Formulations exhibited a mean droplet size in the sub 200 nm range, negative ζ-potential (−60 mV), and displayed non-Newtonian pseudoplastic behavior. The addition of a gelling agent decreased the IAF release from formulations and improved the retention of these compounds in intact porcine ear skin when compared with a control propylene glycol solution. No IAF were detected in receptor fluid of Franz-type diffusion cells. However, increasing amounts of IAF were noticed in both skin layers and the receptor fluid when the tissue was partially injured (tape stripping), or when the epidermis was completely removed. In vitro studies showed that IAF elicits an increased proliferation and migration of keratinocytes (HaCaT cell line). Subsequently, the healing effect of the formulations was evaluated in a model of dorsal wounds in rats, by assessing the size of the lesions, histology, inflammatory markers, and antioxidant activity. Overall findings demonstrated the potential of IAF-loaded formulations to promote wound healing by increasing angiogenesis by ∼200 %, reducing the lipid oxidation (TBARS) by ∼52 % and the inflammation (TNFα) by ∼35 %, while increasing re-epithelialization by ∼500 %, visualized by the epithelium thickness.

Enhanced transdermal delivery of curcumin nanosuspensions: A mechanistic study based on co-localization of particle and drug signals.

Nanosuspensions have received much attention in enhanced transdermal delivery. However, the corresponding mechanisms have not been clarified. In particular, whether nanosuspensions can directly penetrate across the stratum corneum (SC) and what is the transdermal route for the enhanced penetration. Therefore, curcumin (CUR) was adopted in this study as a model drug, while an aggregation-caused quenching (ACQ) probe was physically embedded in CUR nanosuspensions, i.e., the CUR hybrid nanosuspensions (CUR-HNSs), for bioimaging. The ACQ properties enable identification of intact CUR-HNSs. The co-localization of particle and CUR signals was exploited to outline the translocation profiles of intact nanosuspensions as well as the cargoes. Three sizes of CUR-HNSs are prepared, which are spherical and amorphous. CUR is poor in transdermal transport even in propylene glycol solution, which was enhanced by nanosuspensions. Although 400nm CUR-HNSs present higher steady state flux than 140nm and 730nm ones, the cumulative amount of permeated CUR is yet less than 2% of the applied dose at 12h. Co-localization of CUR and ACQ probe signals indicates that CUR-HNSs can infiltrate into the SC layer and accumulate in the hair follicles. The intact CUR-HNSs cannot enter into the skin. On the contrary, CUR molecules diffuse into the whole skin tissues following dissolution of CUR-HNSs in the SC and the hair follicles. In conclusion, nanosuspensions are advantageous for transdermal delivery of poorly permeable drugs by filtrate into the SC and accumulate in hair follicles.

NANOEMULSION OF OKRA FRUIT EXTRACT AS ANTIDIABETIC TREATMENT

Objective: Okra (Abelmoschus esculentus (L.) Moench) has potential antidiabetic activity. This study created a nanoemulsion of okra extract (NOE) and examined its activity on alloxan-induced diabetes mellitus in mice.&#x0D; Methods: Okra was macerated with 70% ethanol and dried in a rotary evaporator into the crude extract. The extract was encapsulated in a solution of glyceryl caprylate, propylene glycol, and glycerine to form a nanoemulsion. To determine the antihyperglycaemic effect of okra extract, 35 male mice (Mus musculus L.) were divided into seven groups: a non-diabetic normal control group and six diabetic mice groups (untreated negative control, glibenclamide-treated positive control, and four treatments with okra ethanol extract (OEE) at 200 and 400 mg/kg BW and NOE at 200 and 400 mg/kg BW).&#x0D; Results: The group treated with NOE at 400 mg/kg BW (NOE400) had the lowest average blood glucose level of 93.4 mg/dL among hyperglycaemic mice. The decrease in blood glucose levels in NOE400 (52.05%) was significantly different from those in the positive control (42.63%) and OEE treatments (39.32%). The nanoemulsion used in this study fulfills quality requirements, with a mean particle size of 134.7 nm, a polydispersity index of 0.512, and a zeta value of −26.72 mV.&#x0D; Conclusion: NOE reduced blood glucose levels in alloxan-induced hyperglycaemic mice better than OEE. Nanoemulsion can improve the antidiabetic activity of okra extract by increasing penetration of active compounds into interstitial space so that their delivery and bioavailability are higher.

Controlled Delivery of Apomorphine Through Buccal Mucosa, Towards a Noninvasive Administration Method in Parkinson's Disease: A Preclinical Mechanistic Study

Apomorphine (APO), a potent treatment for Parkinson's disease, is only administered parenterally either as intermittent injections or as an infusion. This is due to extensive hepatic “first pass” metabolism. Prolonged delivery through buccal mucosa may be potential substitute for parenteral infusions. To investigate this concept of buccal mucosal delivery, permeability ex vivo studies were performed through excised porcine buccal mucosa by utilizing Ussing diffusion chamber. Permeability rates were assessed for APO from simulated saliva medium at pH 7.4 as well as with utilization of different permeability modifying methods. Lowering the pH to 5.9 decreased permeability rate six-fold, while addition of ethanol : propylene glycol solution elevated it four-fold. Addition of nano-scale lipospheres to the donor compartment delayed the accumulation of APO at the receiver side, prolongating the lag-time from one to approx. three hours. These findings were strengthened by results obtained with co-administration of permeability markers (standards) atenolol and metoprolol. Simulation of the obtained permeability rates to in vivo setup in human showed therapeutically relevant plasma levels when using the outcomes of the current study. These findings verify the novel concept of APO prolonged release buccal administration as a noninvasive substitute for parenteral infusions in treating Parkinson's disease.

An experimental study of Al2O3 nаnoparticles influence on caloric properties of propylene glycol based coolants

Nanofluids are promising heat carriers, which contribute to the overall efficiency of energy systems. The main obstacle to the practical application of nanocoolants based on aqueous propylene glycol solutions is the lack of accurate data on their thermophysical properties. In the paper, experimental study (adiabatic calorimetry method) of the heat capacity and parameters of solid phase – liquid phase transitions of propylene glycol and coolant based on aqueous propylene glycol solution is carried out. Experimental study of the heat capacity of the liquid phase of the coolant based on an aqueous solution of propylene glycol with additives of Al 2 O 3 nanoparticles (up to 2.01 wt. %) in the temperature range of 235...338 K and propylene glycol with additives of Al 2 O 3 nanoparticles (1.03 wt. %) in the temperature range of 268…335 K is performed. The comparison of the temperature dependence of the effective heat capacity of coolants with changes in their internal structure is made. It is shown that adding water to propylene glycol increases the temperature and heat of the solid phase – liquid phase transition (the heat of the propylene glycol phase transition is 37.85 J∙g –1 , propylene glycol/water coolant (54/46 wt. %) – 77.97 J∙g –1 ). It is shown that additives of Al 2 O 3 nanoparticles both in propylene glycol and in the coolant based on an aqueous propylene glycol solution contribute to the reduction of the heat capacity of the liquid. The heat capacity decreases approximately in proportion to the increase in the concentration of nanoparticles. The effect of heat capacity reduction is greater at high temperatures (3.9 % at 265 K and 5.0 % at 325 K for the nanocoolant with an Al 2 O 3 nanoparticle concentration of 2.01 wt. %). The results obtained will improve the design quality of heat exchange equipment using nanocoolants. The results are useful for developing methods for predicting the specific heat of nanofluids

Topical Delivery of 3-O-ethyl l-ascorbic Acid from Complex Solvent Systems

3-O-ethyl l-ascorbic acid (EA), an ether derivative of Vitamin C, is widely used in skincare formulations. Previously, we reported the effects of neat solvents on EA percutaneous absorption and observed that 0.6–7.5% of the applied EA was delivered through the skin over 24 h. In this work, we designed complex formulations using combinations of solvents that may act synergistically and examined their impact on EA permeation in porcine skin in vitro under finite dose conditions. Binary combinations of propylene glycol (PG) with propylene glycol monolaurate (PGML) were effective in enhancing skin permeation of EA compared with individual solvents (p &lt; 0.05). Combining PGML with 1,2-hexanediol (HEX) did not result in significantly higher EA permeation compared with the neat solvents (p &gt; 0.05). Addition of the volatile solvent isopropyl alcohol (IPA) to PG solutions also did not improve EA skin delivery compared with neat PG. Ternary solvent systems containing PG:PGML were subsequently prepared by the addition of a lipophilic solvent, either isopropyl myristate (IPM), medium-chain triglycerides (MCT) or isostearyl isostearate (ISIS). The optimum vehicle, PG:PGML:IPM, promoted up to 70.9% skin delivery of EA. The PG:PGML:ISIS vehicles also promoted EA permeation across the skin, but to a significantly lesser extent than the IPM-containing vehicles. No enhancement of EA delivery was noted for the PG:PGML:MCT mixtures. These results will inform the development of targeted formulations for EA in the future.

New Understanding of the Health Hazards of Electronic Cigarettes and Vaping.

1. Harold J. Farber, MD, MSPH* 1. *Baylor College of Medicine and Texas Children’s Hospital, Houston, TX This In Brief was accepted for publication in November 2019. Considering that medical information on the effects of vaping continues to develop, please see the Centers for Disease Control and Prevention (CDC) website on vaping for up-to-date information: https://www.cdc.gov/tobacco/basic_information/e-cigarettes/severe-lung-disease.html. Joseph A. Zenel, MD Editor-in-Chief ​ ​ Electronic cigarettes are addicting a new generation. Although initially promoted as safer than cigarettes and “no tobacco smoke, only vapor,” we are now finding substantial health hazards from these products. Designed to appeal to and promoted to youth, their popularity has surged among middle and high school students, increasing from 1.5% in 2011 to 27.5% in 2019. As a rising tide lifts all boats, after a long period of decline, in 2018 combustible tobacco use among high school students increased. Electronic cigarette use among adolescents and young adults is associated with greater rates of progression to combustible tobacco smoking and progression from intermittent to regular use of combustible tobacco. Electronic cigarettes are referred to by many terms, including e-cigarettes, vape pens, vapes, vaporizers, e-hookah, mechanical mods, Juul, and others. Electronic cigarettes use a heating element or atomizer to create an aerosol from a solution of nicotine, flavoring chemicals, propylene glycol, and glycerin. Other substances may be added. Heating of the solution …

Effects of brodifacoum and diphacinone exposure on four species of reptiles: tissue residue levels and survivorship.

Anticoagulant rodenticides are used worldwide to control pest rodent species. However, the risks posed to non-target reptiles have not been well characterized. In this study, 46 giant ameivas (Ameiva ameiva), 39 boa constrictors (Boa constrictor), 33 wood turtles (Rhinoclemmys pulcherrima), and 47 green iguanas (Iguana iguana) were orally dosed with one of two levels of either diphacinone or brodifacoum anticoagulant in propylene glycol solutions. Dosages were derived using daily food intake (DFI) equations, converting DFI to an equivalent anticoagulant bait amount and gavaging the solution volume needed to deliver the quantity of anticoagulant in that amount of bait. Animals were dosed on days 0 and 7 and monitored for a further 7 days for signs of anticoagulant intoxication and differences in behaviors and postures. At necropsy on day 14, animals were examined for thoracic and abdominal bleeding, and both tissue and organ samples were taken for histology. Liver and whole-body anticoagulant residues were assessed. No turtles or boas died due to anticoagulant exposure. However, anticoagulant intoxication was suspected in one iguana dosed with brodifacoum. A few treated ameivas died but exhibited no hemorrhaging. Liver residue levels were higher than whole-body remainder residue levels for all species. Unlike the other species, turtles had higher diphacinone residue levels than brodifacoum. Turtles and boas exhibited a relative insensitivity to diphacinone and brodifacoum, while the lizards appeared to be somewhat more sensitive to these compounds. This study provides data for future assessments of the risks to these species associated with anticoagulant use. Published 2019. This article is a U.S. Government work and is in the public domain in the USA.

Voriconazole incorporated nanofiber formulations for topical application: preparation, characterization and antifungal activity studies against Candida species

In this study, voriconazole (VCZ) incorporated polyvinyl alcohol/sodium alginate electrospun nanofibers were produced and, then crosslinked with glutaraldehyde for topical antifungal treatment. The nanofibers were characterized in terms of fiber size, surface morphology, and compatibility between drug–polymer and polymer–polymer using scanning electron microscopy, atomic force microscopy, attenuated total reflection-Fourier transform infrared spectroscopy, and high pressure liquid chromatography. After optimization studies, in vitro drug release, skin penetration, and deposition studies were performed using Franz diffusion cells. Antifungal activities of the nanofiber formulations against Candida albicans, Candida tropicalis, and Candida parapysilosis strains were evaluated using susceptibility test and subsequently time-kill study was performed against C. albicans. The cytotoxicity study was performed using 4-succinate dehydrogenase viability assay on mouse fibroblast cell line. The release rate of VCZ from crosslinked nanofibers was slower than that of non-crosslinked nanofibers and Higuchi kinetic model best fitted to the in vitro release data of both of formulations. VCZ deposited in deeper skin layers from nanofiber formulations was higher than that of the control formulation (VCZ solution in propylene glycol (1% (w/v)). According to the susceptibility and time-kill studies, all of the nanofiber formulations showed antifungal activity against C. albicans with confirming no cytotoxicity on mouse fibroblast cells.

Experimental and numerical study of non-stationary solid-liquid phase transitions of n-tetradecane

During the experiments, four spherical flasks with n-tetradecane with a total mass of 0.344 kg were placed in a test container inside which an aqueous solution of propylene glycol with a mass concentration of 50% and an initial temperature of 25 °C was circulating. As a result of studies, the values of heat flows at different time intervals during the solid-liquid phase transition of n-tetradecane were obtained. Based on the modeling of the processes, the distribution of temperature and velocity of the heat carrier in the test container as well as the values of the local heat transfer coefficients on the surface of the flasks were established. Numerical calculations of the process of phase transition being studied according to the authors’ model were also performed. Numerical calculations of the process under study have been performed using the authors’ model. A satisfactory convergence of the experimental and calculated values of the heat flow has been obtained. The results can be used in the development of thermal energy accumulators with n-tetradecane.

The Impact of the Use of Antifreeze Substances on the Heating Installation Thermohydraulic Parameters and Energy Consumption

This article discusses the effect of application of antifreeze substances on thermohydraulic parameters and energy consumption of a heating installation with convective radiators. A comparative theoretical and computational analysis is performed for water and two alternative heating mediums: a 50% aqueous solution of ethylene glycol and propylene glycol. It is indicated that antifreeze substances and their aqueous solutions may cause a reduction in the radiator heat output and an increase in hydraulic resistance, which results in the entire system higher energy consumption and lower efficiency. It is then justified that the heating installation design should take account of the use of a glycol aqueous solution instead of water to avoid an excessive drop in the installation energy indicators and prevent deterioration of the building thermal comfort conditions.

Effect of propylene glycol on the skin penetration of drugs.

Propylene glycol (PG) has been used in formulations as a co-solvent and/or to enhance drug permeation through the skin from topical preparations. Two skin in vitro permeation approaches are used to determine the effect of PG on drug penetration. The in vitro Skin-PAMPA was performed using 24 actives applied in aqueous buffer or PG. PG modulates permeability by increasing or diminishing it in the compounds with poor or high permeability, respectively. Percutaneous absorption using pigskin on Franz diffusion cells was performed on seven actives and their commercial formulations. The commercial formulations evaluated tend to have a lower permeability than their corresponding PG solutions but maintain the compound distribution in the different strata: stratum corneum, epidermis and dermis. The results indicate the enhancer properties of PG for all compounds, especially for the hydrophilic ones. Additionally, the Synchrotron-Based Fourier Transform Infrared microspectroscopy technique is applied to study the penetration of PG and the molecular changes that the vehicle may promote in the different skin layers. Results showed an increase of the areas under the curve indicating the higher amount of lipids in the deeper layers and altering the lipidic order of the bilayer structure to a more disordered lipid structure.

Plasticizer types affect quality and shelf life of eggs coated with rice protein.

The aim of study was evaluate the effect of using rice protein coating with different plasticizers types on the quality of eggs storaged at 20°C for 6weeks. Three hundred eggs were coated with rice protein at 8% solution combined with glycerol, propylene glycol or sorbitol. Uncoated eggs showed the highest weight loss (5.31%), while rice protein with glycerol (4.29%) propylene glycol (4.13%) and sorbitol (4.07%) solutions were effective in preventing weight lost. Uncoated eggs had the worst HU (58.40), albumen (9.52) and yolk (7.06) pH, and YI (0.33) after 6weeks of storage. The eggs coated of rice protein with glycerol, propylene glycol and sorbitol presented results with similar intern quality between them during all the storage period. However, the use of sorbitol as a plasticizer in the coating is more efficient in maintaining control of the increase in albumen pH. Scanning electron microscopy demonstrated a lower surface porosity in coated eggshell, indicating that the use of the coating may provide a protective barrier against the transfer of gases and moisture. In conclusion, the best egg protection results in terms of egg quality are obtained in eggs coated with rice protein and sorbitol.

Microencapsulated PCM slurries’ dynamic viscosity experimental investigation and temperature-dependent prediction model

Microencapsulated PCM (mPCM) slurry is used both as a thermal storage medium and as a heat transfer fluid. The use of mPCM slurry as a working fluid in heat transfer systems requires knowledge of its rheological properties. In this study, experimental research results based on the mPCM product called Micronal® DS 5039 X were used. The research was carried out in the following range: a slurry temperature of 10–50 °C; a mass concentration of microcapsules in the slurry of up to 45%; two types of base liquid (water, an aqueous solution of propylene glycol); a shear rate of 3–130 s−1. This article presents a new temperature-dependent method of calculating the dynamic viscosity coefficient of microencapsulated PCM slurry. The average mean absolute percentage error (MAPE) for the investigated cases was MAPE = 14.19% and MAPE = 12.81% for the Micronal® DS 5039 X slurry in water and the aqueous solution of propylene glycol, respectively. Additionally, the validation of the model was based on the results of other authors’ research. Thus, it was found that 73.1% of the calculated viscosity results of mPCM slurry do not differ by more than 40% from other authors’ experimental results.