Insect repellent N,N-diethyl-m-toluamide (DEET) and sunscreen oxybenzone are commonly incorporated into commercially available consumer care products that are utilized to prevent vector-borne diseases and skin aging and damage. Semisolid emulsion-based formulation has been extensively selected for active repellent and sunscreen ingredients due to their excellent solubilizing properties for both lipophilic and hydrophilic components and satisfactory customer acceptance. Under the ideal use situation, an appropriate and elegant emulsion-based formulation can minimize transdermal absorption of DEET and oxybenzone and maximize their skin protection effect. The percutaneous penetration profiles of DEET and oxybenzone from several emulsion-based formulations were evaluated and compared by using the in vitro diffusion experiments in this thesis. Various parameters in the emulsion formulations, such as emulsion type, emulsifier, emollient, penetration enhancer, thickening agent, and thixotropic properties of the emulsions, could exert significant influence on percutaneous permeation of the active ingredients from the preparations. An emulsion-based preparation using the emulsifier, Emulium 22, possessed the relatively lower skin permeation of DEET and oxybenzone than other emulsion-based preparations; it was selected for the in vivo animal study. This emulsion-based formulation containing DEET and/or oxybenzone was topically applied to rats once daily for a 60-day period to investigate systemic concentration and tissue deposition of DEET, oxybenzone, and their respective metabolites. This formulation produced lower systemic absorption of DEET and oxybenzone than the commercially available products reported in a previous animal study. The concurrent application of DEET and oxybenzone in this study did not show synergistic enhancement between the two compounds in plasma. The percutaneous penetration profiles of DEET and oxybenzone from different semisolid emulsions in the in vitro diffusion experiment provided the important information in selecting the appropriate formulation of DEET and oxybenzone for topical application. The in vivo animal study identified pharmacokinetics and biodistribution characteristics of DEET and oxybenzone from the promising lab-developed emulsion. Studies are ongoing to further improve formulation characteristics so that this emulsion-based preparation could be used to minimize overall transdermal permeation of DEET and oxybenzone from topical skin application.

Zugl.: Berlin, Freie Universiẗat, Diss., 2008.

Though the past two decades have seen a dramatic increase in research toward self-cleaning repellent surfaces, multiple challenges exist in the creation of biorepellent surfaces for everyday use. Environmental concerns persist with many of the chemicals utilized in this field and the need for scalable, low-cost alternatives remains. Spread of pathogens including bacteria and viruses in healthcare and public settings also presents a need for stable surfaces. In the work presented here, we report on the current status of antimicrobial nanomaterials and coatings toward virus repellency, followed by an investigation into the application of polysiloxane nanostructures in creation of flexible hierarchical surfaces. Using n-propyltrichlorosilane (n-PTCS) coated on activated polyolefin (PO) we were able to demonstrate superhydrophobicity, reporting water contact angles above 153° paired with <1° sliding angles on hierarchical surfaces. A transfer assay, that closely mimics contact with high-touch surfaces, using Escherichia coli K-12 transfected with green fluorescent protein (GFP) reported a 1.6-log (97.5%) reduction in fluorescence on surfaces compared to planar PO controls, paired with a 1.2-log (93%) reduction in CFU/mL in comparison to control groups. Additionally, surfaces demonstrated a contact angle of 140.8° with citrated whole blood. Droplets of blood incubated on our surfaces for 15 min showed a 93% reduction in visible staining, while submersion in citrated whole blood for 20 minutes revealed an 87% reduction in blood adhered to the surfaces. The applications for these biorepellent surfaces have widespread potential, including the demonstrated need for prevention of surface contamination to minimize spread of hospital acquired infections (HAIs) within the healthcare system. / Thesis / Master of Applied Science (MASc) / The goal of creating a surface capable of repelling biological samples continues to present challenges due to surface stability, scalability, and cost of manufacturing techniques. Beyond this, many of the existing solutions use fluorine-based chemicals that present a risk to the environment due to the difficulty in breaking down these molecules. This thesis aims to understand the current state of repellent surfaces used for biological applications, including prevention of surface contamination by bacteria and viruses, then investigates the use of more environmentally friendly methods to produce repellent surfaces. Using a silicone-based coating combined with heat induced shrinking of shape memory polymers (SMPs), we have created a flexible surface with multiscale roughness that demonstrates repellency to bacteria and whole blood.

Ixodes ricinus is the main vector of Lyme borreliosis and Tick-borne encephalitis in Europe. Repellents provide a practical means of protection against tick bites and can therefore reduce transmission of tick-borne diseases. In laboratory tests, pieces of cloth treated with MyggA Natural® (a commercial insect repellent) or with the essential oils of Corymbia citriodora (30%), Lavandula angustifolia (1 and 30%), Pelargonium graveolens (1 and 30%), Hyptis suaveolens (10%), Salvadora persica, Pistacia atlantica, Juniperus phoenicea (20%) and methyl jasmonate (MJ) (0.5%, 1.0%, 2.0% and 5.0%) showed strong repellent activity against I. ricinus nymphs. In a tick-infested woodland in east-central Sweden, we tested by randomized, standardised methodology the potential anti-tick repellent activity of MyggA Natural® (roll-on), two concentrations of MyggA Natural® spray, RB86 (a commercially available insect repellent for horses), the essential oil of C. citriodora and three concentrations of MJ. Each substance was dissolved in acetone and applied separately to 1 m2 cloths which were then pulled over vegetation. Nymphal tick numbers on the cloths were recorded at 10-m intervals and differed significantly between treated cloths and the untreated control and also between collectors. Volatile compounds from fresh and dried leaves of H. suaveolens and the essential oils of H. suaveolens (from Laos and Guinea Bissau) and S. persica, P. atlantica and J. phoenicea (from Libya) were collected by solid phase micro-extraction (SPME) and the constituents were identified by gas chromatography - mass spectrometry (GC-MS). Two main sesquiterpene hydrocarbons in the H. suaveolens oil were β-caryophyllene and humulene. These were modified by oxidation and sulphidation to obtain effective tick repellent compounds with lower volatility. In all three oils from Libyan plants the main monoterpene hydrocarbons were α-pinene, sabinene, β-pinene, myrcene, α-phellandrene, 4-carene, β-phellandrene and γ-terpinene. The selected plant species contained numerous volatiles known to have insecticidal, acaricidal, and/or insect repellent properties.

In this thesis, a series of in vitro diffusion studies were performed to evaluate the transmembrane permeation of picaridin and oxybenzone across human epidermis and poly(dimethylsiloxane) (PDMS) membrane. Transdermal permeation of picaridin and oxybenzone from four commercially available repellent and sunscreen products was also investigated by using different application concentrations and sequences. The results obtained were then compared to those of the repellent DEET and the sunscreen oxybenzone under identical experimental conditions. Permeation of picaridin and oxybenzone across human epidermis was suppressed when both compounds were used concurrently. Increasing concentration of the test compounds further reduced the permeation percentage of picaridin and oxybenzone. While permeation characteristics were correlative between human epidermis and artificial PDMS membrane, permeability of PDMS membrane was significantly larger than that of human epidermis. This finding was different from concurrent use of DEET and oxybenzone in which a synergistic permeation enhancement was observed between the two substances. Transdermal permeation of picaridin across human epidermis from various commercially available spray preparations was significantly lower than that of DEET from similar spray products, both alone and in combination with sunscreen oxybenzone. Concurrent application of the commercial products resulted in either no change or suppression of permeation of picaridin and oxybenzone. This finding was also different from concurrent application of DEET and oxybenzone using commercial preparations. In addition, permeation of picaridin and oxybenzone across human epidermis was dependent on application concentration, use sequence, and preparation type.It was concluded from this thesis that picaridin would be a better candidate for concurrent application with sunscreen preparations in terms of percutaneous permeation.

In this thesis, a series of in vitro diffusion studies were performed to evaluate the transmembrane permeation of picaridin and oxybenzone across human epidermis and poly(dimethylsiloxane) (PDMS) membrane. Transdermal permeation of picaridin and oxybenzone from four commercially available repellent and sunscreen products was also investigated by using different application concentrations and sequences. The results obtained were then compared to those of the repellent DEET and the sunscreen oxybenzone under identical experimental conditions. Permeation of picaridin and oxybenzone across human epidermis was suppressed when both compounds were used concurrently. Increasing concentration of the test compounds further reduced the permeation percentage of picaridin and oxybenzone. While permeation characteristics were correlative between human epidermis and artificial PDMS membrane, permeability of PDMS membrane was significantly larger than that of human epidermis. This finding was different from concurrent use of DEET and oxybenzone in which a synergistic permeation enhancement was observed between the two substances. Transdermal permeation of picaridin across human epidermis from various commercially available spray preparations was significantly lower than that of DEET from similar spray products, both alone and in combination with sunscreen oxybenzone. Concurrent application of the commercial products resulted in either no change or suppression of permeation of picaridin and oxybenzone. This finding was also different from concurrent application of DEET and oxybenzone using commercial preparations. In addition, permeation of picaridin and oxybenzone across human epidermis was dependent on application concentration, use sequence, and preparation type.It was concluded from this thesis that picaridin would be a better candidate for concurrent application with sunscreen preparations in terms of percutaneous permeation.

University, Diss., 2005--Düsseldorf.

Biocandle es un modelo de negocio que busca alcanzar la demanda del mercado de repelentes de insectos. Está diseñado en la presentación de una vela aromática que ahuyenta a los insectos y al mismo tiempo proporciona propiedades de aromaterapia que agregan valor a través de las diferentes esencias utilizadas para su elaboración, y a diferencia de otros productos, está hecho con componentes naturales que no son dañinos. a la salud de las personas. El problema que encontramos y, por lo tanto, nos motivó a llevar a cabo este proyecto es que muchas personas tienen problemas con los insectos, sin embargo, no encuentran la manera perfecta de lidiar con ellos, ya que las alternativas que existen actualmente en el mercado no son agradables. para ellos debido al olor y la toxicidad en el caso de tabletas repelentes o repelentes en aerosol y la textura cuando se aplica a la piel en el caso de repelentes en crema. Para comprender el problema, hicimos un análisis del mercado a través de entrevistas y, en consecuencia, pudimos validar el interés en el producto descrito anteriormente. Además, aplicamos diferentes herramientas durante el proyecto, tales como DAFO, marketing y recursos humanos, finanzas y análisis de costos con datos reales de los suministros necesarios para la elaboración y el costo de entrega, entre otros. / Biocandle is a business model that seeks to reach the market demand of insect repellents. It is designed in the presentation of an aromatic candle that drives away insects and at the same time it provides aromatherapy properties which add value through the different essences used for its elaboration, and unlike other products, it is made with natural components that are not harmful to people's health. The problem we have found and therefore, motivated us to carry out this project is that many people have problems with insects, however, they do not find the perfect way to deal with them, since the alternatives that currently exist in the market are not pleasant for them due to the smell and toxicity in the case of repellent tablets or spray repellents and the texture when applied to the skin in the case of cream repellents. To understand the problem, we did an analysis to the market through interviews and in consequence, we were able to validate the interest in the product described above. Moreover, we applied different tools during the project such as SWOT, marketing and human resources, Finance and cost analysis with real data of the supplies needed for the elaboration and delivery cost, among others. / Trabajo de investigación

Breathable water-repellent garments are common products on the outdoor market. There are many recommendations on how to wash and waterproof your garment in order to make sure that its water-repellence is cared for, but the advice given by different sources is inconsistent. Are expensive products really necessarily or are regular laundry products just as good? What waterproofing agents should one use in order to insure that the water-repellent layer is restored? Four different water-repellent wash-in products were tested on polyester and polyamide fabrics. Seven laundry products and two water-repellent wash-in products were tested on jackets with dendrimer based finishes and untreated polyamide fabrics. The results were evaluated by spray testing according to ISO EN 24920 and sessile drop tests. Not all wash-in products offer good water-repellence on polyamide and polyester fabrics. Two laundry detergents decreased the water-repellence of the jackets. The laundry detergents did not affect the function of wash-in waterproofing agents on the jackets. The water-repellence of one wash-in product was affected by the use of two different detergents on untreated fabric / Program: Textilingenjörsutbildningen

Water repellent fabrics with superhydrophobic properties have been constructed during this diploma work. First the fabrics were woven using six different weft yarns creating micro roughness and then a nanoparticle and surface energy lowering treatment was made. Contact angle measurements, contact angle hysteresis measurements, roll-off angle measurements and spray tests were made on the fabrics to investigate the hydrophobicity and water repellence. Also the durability was tested to examine the fastness of the treatments. It was found that the nanoparticles boosted the hydrophobicity of the hydrophobic treatments. Also by varying the size of textile filaments in yarns, the hydrophobicity of the material was affected. In this study, it was found how small textile parameters in the fabric could be changed to increase both durability and water repellence. / Program: Textilingenjörsutbildningen