Film-forming System Research Articles

Design and in vitro/in vivo evaluation of chitosan-polyvinyl alcohol copolymer material cross-linked by dynamic borate ester covalent for pregabalin film-forming delivery system

This research introduced a novel polymer synthesized by combining chitosan and modified polyvinyl alcohol, cross-linked with boric acid using dynamic covalent bonds. The polymer was developed to formulate a pregabalin Film-forming system (FFS) for treating postherpetic neuralgia via topical application, showcasing notable skin adhesion and drug delivery properites. The chitosan-boric acid-modified polyvinyl alcohol polymer was analyzed using NMR, FTIR. The exceptional features of the optimized FFS were evaluated through rheometer, Differential scanning calorimetry (Tg = 45.98 °C), contact angle (θ = 78.62°). The elongation (60.05 ± 3.67 %), cohesion (56.94 ± 4.65 MPa) and skin adhesion (58.12 ± 2.99 kPa) of chitosan-boric acid-modified polyvinyl alcohol were found to be 5.2, 6.8, and 8.3 times higher than those of the pure chitosan film, attributed to the double network structure formed by the cross-linked reversible dynamic covalent bond. The optimized pregabalin FFS exhibited increased in vitro (86.25 ± 1.87 μg/g) and in vivo (100.42 ± 7.44 μg/g) skin retention amounts compared to in vivo oral administration (28.43 ± 4.61 μg/g). In summary, the utilization of borate ester dynamic covalent bonds in developing chitosan-based film-forming polymer proved beneficial in improving skin adhesion and topical therapeutic effectiveness, thereby mitigating the risk of systemic side effects associated with oral administration.

Formulation study of PLGA in situ films for topical delivery of salicylates

A film-forming system (FFS) represents a convenient topical dosage form for drug delivery. In this study, a non-commercial poly(lactic-co-glycolic acid) (PLGA) was chosen to formulate an FFS containing salicylic acid (SA) and methyl salicylate (MS). This unique combination is advantageous from a therapeutic point of view, as it enabled modified salicylate release. It is beneficial from a technological perspective too, because it improved thermal, rheological, and adhesive properties of the in situ film. DSC revealed complete dissolution of SA and good miscibility of MS with the polymer. MS also ensures optimal viscoelastic and adhesive properties of the film, leading to prolonged and sustained drug release. The hydrolysis of MS to active SA was very slow at skin pH 5.5, but it apparently occurred at physiological pH 7.4. The film structure is homogeneous without cracks, unlike some commercial preparations. The dissolution study of salicylates revealed different courses in their release and the influence of MS concentration in the film. The formulated PLGA-based FFS containing 5 % SA and 10 % MS is promising for sustained and prolonged local delivery of salicylates, used mainly for keratolytic and anti-inflammatory actions and pain relief.

Spray: Film Forming System Promising as Transdermal Drug Delivery System

Transdermal drug delivery systems offer numerous advantages over conventional routes, including improved patient compliance and reduced systemic side effects. Spray-on film forming systems (SFFS) have emerged as a novel and versatile approach for delivering drugs through the skin. This abstract presents an overview of SFFS technology, highlighting its potential in transdermal drug delivery. SFFS formulations consist of a solution or suspension of drug molecules and polymers, which upon spraying onto the skin, form a thin, uniform film that adheres to the application site. This film acts as a reservoir for drug release, providing controlled and sustained delivery over time. The versatility of SFFS allows for the incorporation of various drugs, including small molecules, peptides, and proteins, catering to a wide range of therapeutic needs. Moreover, SFFS offers advantages such as ease of application, improved bioavailability, and enhanced skin permeation compared to traditional dosage forms. This abstract summarizes recent advancements in SFFS technology, including formulation strategies, characterization methods, and in vitro/in vivo evaluations. Additionally, challenges such as skin irritation, film integrity, and scalability are discussed, along with potential solutions. Overall, SFFS holds great promise as a transdermal drug delivery system, offering opportunities for enhanced therapeutic outcomes and patient convenience.

Study of antimicrobial properties of liquid plaster containing of oregano essential oil (Origanum vulgare L.)

Treatment of wounds resulting from combat injuries is complicated by the addition of a secondary infection caused by multi-resistant bacteria. The liquid patch appears to be a promising formulation for wound therapy. The antimicrobial effect of essential oils is manifested due to the content of numerous components that interfere with the proliferation and formation of bacterial resistance. The aim of the work was to substantiate the choice of Origanum vulgare L. essential oil as the main active ingredient of a liquid patch with antimicrobial action, confirm the composition of the essential oil and study the antimicrobial properties of the model drug. The object of the study were model samples of a liquid patch with an experimentally developed film-forming system. Various concentrations of commercial essential oil of O. vulgare L., the composition of which was confirmed by GB/MS analysis, were used as the active pharmaceutical ingredient. Antimicrobial activity was studied by direct contact method using microbial culture tests. The use of liquid patch in the treatment of skin lesions of various etiologies, including combat wounds, is justified. The variability of the composition of the essential oil of O. vulgare L. depending on the subspecies, chemotype and growth conditions of the plant is discussed. The component composition of a commercial sample of O. vulgare L. essential oil, confirmed by GC/MS analysis, is considered. 11 components declared by the manufacturer were found to be completely identical, in particular, carvacrol, thymol, and monoterpene hydrocarbons. The other 11 compounds discovered were monoterpenoids and sesquiterpenoids. Research has confirmed the feasibility of using O. vulgare L. essential oil, thymol-carvacrol chemotype, as an antimicrobial component. The dependence of the antimicrobial activity of model samples of liquid plaster on the concentration of Oregano essential oil was established. The essential oil of O. vulgare L. has a variable composition and requires mandatory control of the content of thymol and carvacrol, which inhibit the growth of the studied microorganisms. The antimicrobial effect of a liquid patch containing essential oil of O. vulgare L. at a concentration of 0.15 mg/ml is manifested against test cultures of microorganisms – Escherichia coli, Klebsiella pneumoniae, Staphylococcus aureus, Enterococcus faecalis.

Fabrication and in vitro characterization of curcumin film-forming topical spray: An integrated approach for enhanced patient comfortandefficacy.

Curcumin, known for its anti-inflammatory properties, was selected for the developing consumer friendly film forming spray that offers precise delivery of curcumin and and improves patient adherence. An optimized film-forming solution was prepared by dissolving curcumin (1%), Eudragit RLPO (5%), propylene glycol (1%), and camphor (0.5%) in ethanol: acetone (20:80) as the solvent. The solution was filled in a spray container which contained 70% solutions and 30% petroleum gas. In-vitro characterization was performed. Potential anti-inflammatory phytoconstituents were extracted from the PubChem database and prepared as ligands, along with receptor molecules (nsp10-nsp16), for molecular docking using Autodock Vina. The docking study showed the lowest binding energy of -8.2 kcal/mol indicates better binding affinities. The optimized formulation consisted of ethanol:acetone (20:80) as the solvent, Eudragit RLPO (5%) as the polymer, propylene glycol (1%) as the plasticizer, and camphor oil (0.5%) as the penetration enhancer. The optimized formulation exhibited pH of 5.8 ± 0.01, low viscosity, low film formation time (19.54 ± 0.78 sec), high drug content (8.243 ± 0.43 mg/mL), and extended ex vivo drug permeation (85.08 ± 0.09%) for nine hours. Consequently, the formulation was incorporated into a container using 30% liquefied petroleum gas, delivering 0.293 ± 0.08 mL per actuation, containing 1.53 ± 0.07 mg of the drug. The film-forming spray exhibited higher cumulative drug permeation (83.94 ± 0.34%) than the marketed cream formulation and pure drug solution after 9 h, with an enhancement ratio of 14. Notably, the film-forming spray exhibited no skin irritation and remained stable for over three months. The developed curcumin film-forming system is promising as a carrier for wound management because of its convenient administration and transport attributes. Further in vivo studies are required to validate its efficacy in wound management.

Combining protection with skin health: In vivo studies of an innovative gelatin/tannic acid-based hydrogel patch to prevent PPE-related skin lesions

The prolonged use of Personal Protective Equipment (PPE) can lead to skin problems due to persistent pressure, friction, and tension. This issue has prompted the exploration of solutions to protect the skin while maintaining the effectiveness of the PPE. This study aimed to evaluate the in vivo effectiveness of a gelatin/tannic acid-based hydrogel patch positioned beneath a mask to alleviate skin damage resulting from mask-wearing. To understand the pressure exerted by PPE, in vitro tests were conducted to measure the tensile strength of three types of facial masks. The FFP2 masks exhibited the highest tensile strength and were selected for subsequent in vivo biometric investigations. Biometric parameters were evaluated using the Flir E50bx® thermographic camera, Corneometer®, MoistureMap®, Sebumeter®, Tewameter®, and VISIA® systems. The results showed that when the hydrogel patch was used under the mask, there were no significant differences in facial skin temperature, sebum levels, or TEWL values (p > 0.05). However, a statistically significant increase in skin hydration and a decrease in frontal redness (p < 0.05) were observed. Consumer acceptance was assessed through sensory analysis questionnaires. In summary, the observed attenuation of physiological changes in the facial area and the positive consumer feedback suggest that this polymeric film-forming system is a simple yet effective solution to prevent PPE use-related skin issues.

The Influence of Lyophobicity and Lyophilicity of Film-Forming Systems on the Properties of Tin Oxide Films

In this work, the effects of lyophobicity and lyophilicity of film-forming systems on the properties of thin nanostructured films was studied. Systematic series of experiments were carried out with lyophilic film-forming systems: SnCl4/EtOH, SnCl4/EtOH/NH4F, SnCl4/EtOH/NH4OH and lyophobic systems: SnO2/EtOH and SnO2/EtOH/NH4F. Film growth mechanisms are determined depending on the type of film-forming system. The surface of the films was studied using a scanning electron microscope and an optical microscope. The spectrophotometric method is used to study the transmission spectra and the extinction coefficient. The surface resistance of the films was determined using the four-probe method. The quality factor and specific conductivity of the films are calculated. It was found that the addition of a fluorinating agent (NH4F) to a film-forming system containing SnO2 in the form of a dispersed phase does not lead to an increase in the specific conductivity of the films. X-ray diffraction analysis proved the incorporation of fluorine ions into the structure of the film obtained from the SnCl4/EtOH/NH4F system by the presence of SnOF2 peaks. In films obtained from SnO2/EtOH/NH4F systems, there are no SnOF2 peaks. In this case, ammonium fluoride crystallizes as a separate phase and decomposes into volatile compounds.

Bioprospecting a Film-Forming System Loaded with Eugenia uniflora L. and Tropaeolum majus L. Leaf Extracts for Topical Application in Treating Skin Lesions.

Natural products can be used as complements or as alternatives to synthetic drugs. Eugenia uniflora and Tropaeolum majus are natives of Brazil and have antimicrobial, anti-inflammatory, and antioxidant activities. This study aimed to develop a film-forming system (FFS) loaded with plant extracts with the potential for treating microbial infections. E. uniflora and T. majus leaf extracts were prepared and characterized, and the individual and combined antioxidant and antimicrobial activities were evaluated. The FFS was developed with different concentrations of polyvinylpyrrolidone (PVP) and polyvinyl alcohol (PVA) and analyzed for physicochemical characteristics. The combination of extracts showed a superior antioxidant effect compared to the individual extracts, justifying the use of the blend. FFS prepared with 4.5% PVA, 4.5% PVP, 7.81% E. uniflora extract, and 3.90% T. majus extract was adhesive, lacked scale formation, presented good malleability, and had a suitable pH for topical application. In addition, the viscosity at rest was satisfactory for maintaining stability; water solubility was adequate; skin permeation was low; and the antimicrobial effect was superior to that of the individual extracts. Therefore, the developed FFS is promising for the differentiated treatment of skin lesions through topical application.

Prevention of skin lesions caused by the use of protective face masks by an innovative gelatin-based hydrogel patch: Design and in vitro studies

The recent Covid-19 pandemics led to the increased use of facial masks, which can cause skin lesions due to continuous pressure, tension and friction forces on the skin. A preventive approach is the inclusion of dressings between the face and the mask. However, there are still uncertainties about the protective effect of dressings and whether their use compromises the efficiency of masks.The current study aimed to develop and test the efficacy of a gelatin-based hydrogel patch to be placed between the mask and the facial area. Design of Experiment with a Quality by Design approach tools were used in the patch development and in vitro characterization was performed through rheological evaluation, ATR-FTIR and molecular docking studies. Furthermore, tribology studies were performed to test the patch performance.The results showed that the addition of excipients enhanced gelation temperature, elasticity and adhesiveness parameters. The interactions between excipients were confirmed by ATR-FTIR and molecular docking. The tribology assay revealed similar friction values at room and physiological temperature, and when testing different skin types.In conclusion, the physical properties and the performance evaluation reported in this study indicate that this innovative film-forming system can be used to prevent skin lesions caused by the continuous use of protective masks.

Construction of Imatinib Controlled Release Film-Forming System Based on Drug Ion-Pair and Oligomeric Ionic Liquids for the Long Local Therapy of Cutaneous Melanoma.

An imatinib controlled release film-forming system (FFS) was developed based on the drug ion-pair and newly designed oligomeric ionic liquids (OILs) for the topical therapy of cutaneous melanoma, which avoided the systemic side-effect of oral administration and maintained a long local therapy effect. The OILs significantly improved the drug release capacity about 1.5-fold, and the formability and stability of FFSs (verified by AFM/PLM). The in vivo anti-tumor efficacy studies in melanoma tumor bearing mice showed that compared with the oral capsules, the topical application of the optimized imatinib FFS significantly (p < 0.01) increased tumor inhibition rate (67.54 ± 2.72%) and the amount of apoptotic cells. As confirmed by FT-IR and NMR, the partial protonation of OILs were demonstrated to have high hydrogen bond forming capacity, thus showing low polarity and good biocompatibility. More importantly, based on 13C-NMR study, OILs demonstrated higher hydrogen bond forming capacity, and formed bridge between drug ion-pair (O-H of counter-ion) and PVA (O-H), increased the molecular mobility of PVA, thus maintaining a long drug release capacity. Therefore, an imatinib FFS was developed with good therapeutic effect and the effect of drug ion-pair and OILs on increasing the drug skin retention and controlled release of imatinib FFS for topical therapy was clarified at the molecular level, which provided a safe and effective way for the treatment of cutaneous melanoma.

A Green Film-Forming Investigation of the Edible Film Based on Funoran: Preparation, Characterization, and the Investigation of the Plasticizer Effects.

In this study, an edible film based on funoran was developed. Moreover, the effects of plasticizers (glycerol, xylitol, and sorbitol) on the physicochemical properties of the funoran films were also investigated. The interactions between plasticizers and funoran molecules of the film-forming system were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy. The results showed that the addition of plasticizers altered and broke the initial complex entangled structures of funoran molecular chains. Funoran films containing plasticizers were compatible, homogeneous, and dense, exhibiting good thermal stability below 100 °C. With the addition of plasticizers, the elongation at break, oxygen permeability, light transmittance, and water vapor permeability increased, but the tensile strength decreased. It was found that a glycerol addition of 40% was most suitable for commercial applications. All the results revealed the excellent film-forming properties of funoran, indicating that the prepared funoran films have tremendous potential for packaging applications.

Development and Evaluation of a Film Forming System Containing Myricetin and Miconazole Nitrate for Preventing Candida albicans Catheter-Related Infection.

Background: Candida albicans catheter-related infection (CRI) is a great challenge in clinic now, mainly due to the difficulty in eradicating the biofilms. Purpose: In this study, the mechanism of the antibiofilm effect of myricetin (MY) on C. albicans was illustrated. A film forming system (FFS) containing MY and miconazole nitrate (MN) was developed, optimized, and evaluated. The anti-infection effect of MY+MN@FFS against C. albicans CRI was investigated in vivo. Study Design and Methods: To clarify the mechanism of the action of MY, the influence of MY on each key process of the formation of C. albicans biofilms was evaluated. To deliver MY and MN into the skin and form a drug reservoir on the surface of the skin, the FFS was used as a carrier and MY+MN@FFS was developed, optimized, and evaluated. After preliminary confirmation of drug safety, a percutaneously inserted C. albicans CRI mouse model was established to investigate the in vivo anti-infection effect of MY+MN@FFS by fluorescence microscopy and scanning electron microscopy on the outer surface of the catheters, hematoxylin/eosin staining, and periodic acid-Schiff staining of the mice skin tissues. Results: MY was found to inhibit the morphological transition of C. albicans and the secretion of exopolysaccharides, resulting in a reduction in biofilms. MY+MN@FFS exhibited excellent properties and no irritation to mice skin. In an in vivo anti-infection study, MY+MN@FFS exhibited an excellent preventive effect against percutaneously inserted C. albicans CRI. Conclusion: MY+MN@FFS might be a potential approach for effectively preventing percutaneously inserted C. albicans CRI in clinic.

The effect of non-invasive dermal electroporation on skin barrier function and skin permeation in combination with different dermal formulations

PurposeThe aim of this research was to investigate the effect of non-invasive dermal electroporation (EP) on the barrier function of the skin and on the permeation of a model macromolecule in combination with different dermal formulations. MethodsSkin samples were treated with non-invasive dermal EP treatment for 2 min. Firstly, the effect of EP on the barrier function of the skin was examined on mouse skin in vivo by measuring transepidermal water loss (TEWL). Then, the effect of EP on human skin permeation was investigated ex vivo under a fluorescence microscope in combination with different dermal formulations. The human skin was treated with a solution, a hydrogel, and a film-forming system (FFS) containing 4 kDa fluorescein isothiocyanate-dextran (FITC-dextran) with or without EP. The increased fluorescence intensity shows the presence of FITC-dextran in the skin layers. ResultsThe results showed, that the TEWL values increased rapidly after the treatment, and it took approximately 5 min to be restored. The results of permeation experiments showed that just slight permeation of FITC-dextran could be noticed from any formulation without EP; however, the permeation from the solution and the FFS increased highly in combination with EP. ConclusionThe EP decreased the barrier function of the skin reversibly and the structure of SC was restored in a short time after the treatment. FITC-dextran, as a macromolecule, can just slightly permeate into the skin with passive diffusion. EP could increase the permeation rate of FITC-dextran remarkably compared to the control treatments; however, the composition of the formulations has a great influence on the permeation.

Development and Evaluation of Liquid Plaster Loaded with Chromolaena odorata Leaf Extract Endowed with Several Beneficial Properties to Wound Healing.

Liquid plaster (LP) is a recently developed wound dressing product that can be used to cover wounds in various parts of the body, especially small injuries or wounds in body parts involved in movement. Given the benefits and applications of LP, this study aimed to develop and evaluate Chromolaena odorata extract-loaded LP with antimicrobial and hemostasis effects. The study was first conducted through the extraction of Choromolaena odorata leaf by using an ethanol maceration technique and identification of the compounds with high-performance liquid chromatography. The LP loaded with Chromolaena odorata extract demonstrates an ability to inhibit S. aureus and S. epidermidis at a MIC of 0.25 mg/mL and MBC of 0.5 mg/mL. The antioxidant activity test was performed by ABTS and DPPH methods demonstrating the free-radical scavenging activity of the extract. The blood clotting activity was established by varying the concentration of Choromolaena odorata leaf extract from 0.0625 mg/mL to 1 mg/mL. The formulation of the film-forming system was developed by varying the solvent, polymer, and plasticizer proportions. The optimum formulation displayed fast film-forming with high elasticity of the film. Moreover, the 20 mg/mL herbal extract-loaded LP provided an antibacterial effect with admissible water vapor transmission and low skin irritation. As a result, the study demonstrates the possibility of introducing the Chromolaena odorata extract-loaded LP to increase the effectiveness of wound healing and the antibacterial effect on the skin.

Size effect of γ-MnO2 precoated anode on lead-containing pollutant reduction and its controllable fabrication in industrial-scale for zinc electrowinning

Lead (Pb) is the most widely used anode in zinc (Zn) electrowinning and other metallurgical industries. The resource loss and environmental pollution caused by Pb anode corrosion are urgent problems to be solved. A γ-MnO2 precoated anode was prepared successfully to reduce the Pb-containing pollutant. The size effects with its controllable preparation on an industrial scale were studied. Severe nonuniform distribution of γ-MnO2 film was observed with curbing the reduction of anode slime only 68%, when anode size increased from lab to industry. Nonuniform rate (R) and average thickness (d) were found to be the key indicators to determine the film structure distribution and their performance differences, which were random and difficult to be controlled in scale-up size. However, a controllable industrial γ-MnO2 precoated anodes (IMPA) fabricated through optimized current density (J0) and electrodeposition time (t) in our developed film-forming system. Then, the long-term performances of two IMPA with different indicators (IMPA-1: R = 34%, d = 108 μm, IMPA-2: R = 23%, d = 55 μm) were compared with the industrial typical Pb-based anode (ITPA). Of the three different anodes, the optimized IMPA-2 displayed the best performance. Within 24 d of electrowinning cycle, the corrosion inhibition effect and the anode slime reduction rate for IMPA-2 improved by 56% and 30% than IMPA-1, and improved by 100% and 91% than ITPA. Furthermore, the mechanism analysis of size effect change showed that R of IMPA was contributed to the local gas holdup distribution along the anode. Controlled size effect of uniform oxide film will have a future application prospect for the sustainability of industry, which provides an important cleaner production of Zn electrowinning and related hydrometallurgy industries.

Fabricating an anti-shrinking κ-carrageenan/sodium carboxymethyl starch film by incorporating carboxylated cellulose nanofibrils for fruit preservation

A stronger and dimension-stabilized film was obtained using κ-carrageenan and sodium carboxymethyl starch (CMS) with carboxylated cellulose nanocrystals (C-CNC) as a reinforcing agent and anti-shrinkage agent. C-CNC endowed the films with better mechanical properties as well as excellent dimensional stability. The film solutions showed shear thinning and acted as a pseudoplastic fluid. When C-CNC content was increased from 0% to 12%, the tensile strength and elongation at break of the films improved from 23.89 MPa to 38.37 MPa and 21.00% to 27.31%, respectively. The films maintained good thermal stability and barrier performance. The Zeta potential of the film suspension can reach below −30 mV, indicating C-CNC enhanced the electrostatic repulsion in the film-forming system, which favored the network structure more continuous and stable. By virtue of the excellent mechanical properties and dimensional stability, strawberries can be tightly wrapped without cracks by the coatings to delay the deterioration greatly. By comparing the weight loss rate, Vc, total soluble solid, hardness, titratable acid and pH, CCC12-coated strawberries were closer to fresh ones. Therefore, this study has developed a feasible, low-cost and green fruit coating that can be potentially utilized on a large-scale.

Enhancing chitosan solubility in alcohol: water mixtures for film-forming systems releasing with turmeric extracts

BackgroundFilm-forming system (FFS), a non-solid dosage form, are attractive drug delivery system for the topical drug administration due to ability to form a film in situ on a skin after spraying or applying. To minimize drying time, alcohol is often used as a solvent in the system. The aim of this research was to enhance chitosan solubility in alcoholic solution by chemical modification of chitosan, i.e., reductive amination and Michael addition reaction, for film-forming systems with efficient releasing of turmeric extract. MethodsAlcoholic-soluble chitosan derivative (CBA) was synthesized by reductive amination, followed by a Michael reaction. Its structure was investigated by FT-IR, 1H NMR and XRD techniques. The CBA was incorporated with β-cyclodextrin encapsulated turmeric extract (CDTE) to prepare film-forming solution. Significant FindingsThe results confirmed that the CBA was successful prepared, as the new peaks were observed by FT-IR and 1H NMR, with good solubility in 50% aqueous alcoholic solution. The CBA-based film, derived from the solvent evaporation, exhibited nontoxic to HaCaT cells. Moreover, the films containing CDTE had smooth surfaces and released turmeric extract (74%) more effectively than films containing the extract alone (43%). The CBA-based ethanolic solution (30–50%v/v ethanol) could dry within ~6–9 min and form a thin film on human skin. ConclusionsThus, the CBA-based solution with CDTE has potential as a film-forming system based on natural products.

Effectiveness of finishes in protecting wood from liquid water and water vapor

Wood is increasingly used in the bathrooms for furniture due to its beauty, warm and organic look, but also for floors, walls, and even for wooden sinks and bathtubs. Wood in the bathroom is exposed to changes in temperature and humidity as well as spillage and splashing of water and should therefore be properly finished with an effective coating to protect it from extreme changes in moisture content. In this research ash and larch wood were finished with penetrating and film-forming coatings and subsequently were exposed to liquid water and water vapor. During exposure to liquid water and water vapor, the mass of the samples and the moisture content in the samples were measured. Results showed that penetrating coatings provided some protection against liquid water absorption but very little protection against water vapor, especially on ash wood. Moreover, the moisture excluding effectiveness reduced rapidly during exposure to high humidity and depending on the wood species and coating systems. • Wood species did not affect liquid water uptake of wood finished with an alkyd film-forming system. • Penetrating coatings should be used in the bathroom only on durable wood species. • Penetrating coatings provided some protection against liquid water absorption, but they provide very little protection against water vapor. • Moisture excluding effectiveness reduced rapidly during exposure to high humidity and depending on the wood species and coating systems.

PLGA based film forming systems for superficial fungal infections treatment

As proven in clinical trials, superficial fungal infections can be effectively treated by single topical application of terbinafine hydrochloride (Ter-HCl) in a film forming system (FFS). Poly(lactic-co-glycolic acid) (PLGA) derivatives, originally synthesized with intention to get carriers with optimized properties for drug delivery, and multifunctional plasticizers - ethyl pyruvate, methyl salicylate, or triacetin - were used for formulation of Ter-HCl loaded FFSs. After spraying, a biodegradable, transparent, adhesive, and occlusive thin layer is formed on the skin, representing drug depot. In situ formed films were characterized by thermal, structural, viscoelastic, and antifungal properties as well as drug release and skin penetration. DSC and SEM showed fully amorphous films with Ter-HCl dissolved in PLGA in high concentration (up to 15%). FFSs are viscoelastic fluids with viscosity which can be easily adjusted by the type of plasticizer used and its concentration. The formulations showed excellent bioadhesion properties, thus ensuring persistence on the skin. In situ film based on branched PLGA/A plasticized with 10% of ethyl pyruvate allowed prolonged release of Ter-HCl by linear kinetics for the first 6 days with a total time of almost 14 days. During ex vivo human skin penetration experiment, Ter-HCl was found to be located only in its target layer, the epidermis. According to our results, plasticized branched PLGA derivatives loaded by Ter-HCl are suitable for the development of FFSs for superficial fungal infections treatment.

The effect of three-minute exposure of oxygen plasma on the properties of tin oxide films

Research devoted to the effect of three-minute exposure of oxygen plasma on the properties of tin oxide films investigation. The films were obtained by sol-gel method from five-water tin tetrachloride solution. The concentration of tin ions in the SnCl4/EtOH film-forming system was 0.14 mol/l. The solution system was deposed on the glass substrate by carring out a modified dipping method. Plasma treatment was performed at a pressure of 6.5 Pa and a power of about 20 Watts. The frequency of the oscillations produced by the generator was 27.12 ± 0.6 % MHz as well. The temperature of the samples during processing did not exceed 100 ºC. As a result of the formation of tin oxide (II), the film transmittance decreased after treatment with oxygen plasma. The width of the electric forbidden zone of the obtained samples was calculated, which was 3.95 eV for glass and 3.79 eV for film. The resistance of the films was determined by 10 measurements on different parts of the samples. The film without processing has a resistance of about 4255 ± 1158 kΩ, after processing, the resistance decreased by 25 times and amounted to 167 ± 26 kΩ. A decrease in resistance indicates an increase in the concentration of charge carriers in the sample. The resulting SnO is a semiconductor that lowers the transmittance of the studied films and contributes to reducing their resistance. X-ray structural analysis of the samples was also performed. After processing in oxygen plasma, the intensity of reflection from the (110) plane have increased. It should be noted that the number of planes with (101) indexes has decreased. The study of the sample surface showed the destructive nature of three-minute exposure by oxygen plasma.