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Micelizacijsko ponašanje površinski aktivnih tvari od povećanog je interesa za istraživače zbog brojnih primjena u raznim poljima kao što su kozmetika, farmaceutski proizvodi, deterdženti, itd. Fenomen agregacije površinski aktivnih tvari proučavan je u raznim medijima kao što je voda, nepolarna i polarna otapala, elektroliti i smjese otapala. Istraživanja u raznim smjesama otapala su bitne se kako bi se dobio bolji uvid u mikroskopsko ponašanje i poboljšale performanse površinski aktivnih tvari s naglaskom na c.m.c i termodinamiku micelizacijske reakcije jer se na taj način mogu optimizirati svojstva otopina za razne komercijalne primjene. Prisutnost polarnog organskog otapala kao dodatka može značajno utjecati na termodinamička svojstva micelarnog koloida ionskog tenzida u vodi. Glikoli su alkoholi koji u svojoj strukturi imaju dvije hidrofilne -OH skupine i hidrofobnu skupinu ugljikova lanca, te su obje skupine sposobne za interakciju s ionskim površinski aktivnim tvarima u otopini kada su prisutni u smjesi s vodom. U ovom radu konduktometrijski je ispitivan utjecaj smjese propan-1,2-diol/voda na micelizacijsku reakciju SDS-a s fokusom na utjecaj duljine alkilnog lanca, temperature i koncentracije glikola. Zatim je iz temperaturne ovisnosti izmjerenih parametara izračunata termodinamika ovog procesa koja uključuje i entalpijski i entropijski doprinos prema standardnoj Gibbsovoj energiji micelizacije., Surfactant´s micellization behavior is very interesting to researchers due to numerous applications in various fields such as cosmetics, pharmaceuticals, detergents, etc. The phenomenon of surfactant aggregation has been studied in various solutions such as water, nonpolar and polar solvents, electrolytes and solvent mixtures. Research in various solvent mixtures is essential in order to obtain a better insight into the microscopic behavior and improve the performance of surfactants with emphasis on c.m.c and thermodynamics of the micellization reaction and to optimize the properties of solutions in various commercial applications. The presence of a polar organic solvent as an additive can significantly affect the thermodynamic properties of the micellar colloid of the ionic surfactant in water. Glycols are alcohols with two hydrophilic -OH groups and a hydrophobic carbon chain group, and both groups are capable to interact with ionic surfactants in solution when present in a mixture with water. In this thesis, the influence of the propylene-glycol/water mixture on the micellization reaction of SDS was conductometrically investigated with a focus on the influence of the alkyl chain length, temperature and glycol concentration. Then, from the temperature dependence of the measured parameters, the thermodynamics of this process was calculated, which includes both enthalpy and entropy contribution according to the standard Gibbs free energy of micellization.

Uvod: Ljudski in vivo modeli oštećenja kože se koriste za ispitivanje djelotvornosti topikalnih terapija kožnih bolesti i oštećenja, među kojima se ističe model iritativnog dermatitisa induciranog natrijevim laurilsulfatom (SLS). Provođenje modela se uvelike razlikuje između različitih istraživačkih skupina, s različitim anatomskim lokacija na kojima su se istraživanja provodila. Osim navedenog modela koji predstavlja kemijsku iritaciju, često su korišteni modeli mehaničke iritacije tape-stripping postupkom te fizikalno oštećenje kože ultraljubičastim zračenjem. Cilj: Ispitati postojanje razlika u odgovoru kože na iritaciju i cijeljenje u akutnom modelu iritativnog dermatitisa izazvanog SLS-om na podlakticama i leđima te usporediti razlike u odgovoru kože na tri različita modela oštećenja kože u istim uvjetima, na istim ispitanicima te na istoj anatomskoj lokaciji. Materijali i metode: Provedena su dva randomizirana klinička pokusa. U pokusu 1 je na podlakticama i leđima inducirana iritacija SLS-om, uz kontrolnu iritaciju vodom. U pokusu 2 su na podlakticama inducirana oštećenja kože u tri različita modela oštećenja kože. U oba pokusa su praćene nastale promjene kožnih parametara neinvazivnim mjerenjima i oporavak kože, uz primjenu i bez primjene topikalne terapije. Rezultati: U pokusu 1, koža gornjeg dijela leđa je pokazala snažniju reakciju na iritanse, ali i brži oporavak kože. U pokusu 2, u modelu iritacije SLS-om je došlo do najsnažnijeg oštećenje kože i odgođene reakcije na iritans. Tape-stripping je doveo do najsnažnijeg početnog oštećenja kožne barijere, ali koža je nakon te nokse pokazala najbrži oporavak. Ultraljubičasto zračenje nije imalo učinka na funkciju kožne barijere, ali je dovelo do nastanka eritema i promjene razine melanina. Topikalne terapije u dva pokusa nisu dovele do poboljšanja mjerenih parametara kože. Zaključak: Osjetljivost kože na iritans i stopa oporavka kože nakon iritacije su ovisne o anatomskoj lokaciji. Tri ispitivana modela oštećenja kože su imala značajno različite učinke na parametre kože te različit oporavak nakon noksi., Introduction: Human in vivo models of skin damage are often used to test the effects of different topical treatments. Commonly used model is irritant contact dermatitis induced by chemical irritant, sodium laurylsulphate (SLS). There is no uniform approach to SLS testing, as different research groups use significantly different variations of the model, especially in regards to anatomical location where testing was conducted. Other commonly used skin damage models include tape-stripping as mechanical and ultraviolet radiation as physical skin damage model. Objective: The aim was to investigate differences in skin response to acute irritation induced by SLS and skin recovery between forearms and upper back, as well as to compare skin parameters in three different skin damage models on the same participants and anatomical location, in the same research conditions. Materials and Methods: Two randomized, controlled trials were conducted. In the trial 1, the skin irritation was induced using SLS on the forearms and upper back of the participants, with sham irritation, using water instead of SLS, as control. In the trial 2, the three skin damage models were induced on test sites on participants’ forearms. Changes in skin parameters and skin recovery in both trials were assessed using non-invasive bioengineering methods, with and without topical treatment. Results: In the trial 1, the skin of the upper back had significantly stronger reaction to irritant, as well as higher skin recovery rates. In trial 2, three tested skin damage models led to different changes of the skin parameters. Irritation by SLS induced the strongest skin damage and also showed delayed reaction to the irritant. The strongest initial barrier disruption was noted after tape-stripping. Also, tape-stripped skin had the highest recovery rates. Ultraviolet radiation did not have any effect on skin barrier function and only changed skin erythema and melanin values. Measured parameters were not improved by topical treatments in neither trial. Conclusion: The skin’s reaction to irritant and recovery was dependent on anatomical location. Three tested models had distinctive responses to skin damage and recovery.

Cilj istraživanja: Utvrditi pokazuje li ispitivani pripravak gospine trave zaštitne i obnavljajuće učinke na koži u ljudskom modelu iritacijskog kontaktnog dermatitisa izazvanog natrijevim laurilsulfatom (SLS-om). Materijali i metode: Temelj istraživanja je randomizirani kontrolirani pokus koji je proveden 2019. godine na 14 odraslih, zdravih ispitanika bez kožnih bolesti u anamnezi, a odvijao se na Medicinskom fakultetu u Splitu. Korištenjem Finnovih komora koje sadrže SLS, ispitanicima je eksperimentalno izazvan iritacijski kontaktni dermatitis, a ispitivana područja kože bile su podlaktice ispitanika. U terapiji su korištena dva pripravka od kojih je jedan sadržavao aktivnu tvar (Hypericum perforatum), dok je drugi pripravak bio placebo. Učinkovitost ispitivanog pripravka praćena je mjerenjem vlažnosti kože, eritema, melanina i transepidermalnog gubitka vlažnosti kože (TEWL) korištenjem uređaja MPA 6 (Courage+Khazaka, Koln, Njemačka) s tri sonde (Mexameter, Corneometer, Tewameter). Rezultati: Ispitivani pripravak na bazi gospine trave nije pokazao statistički značajne razlike u vrijednostima mjerenih parametara kože (eritem, vlažnost kože, melanin i TEWL) u odnosu na placebo pripravak. Zaključci: Ovim istraživanjem nije dokazana djelotvornost gospine trave u poboljšanju svojstava barijere kože na ljudskom modelu iritacijskog kontaktnog dermatitisa eksperimentalno izazvanog SLS-om. Potrebno je provesti dodatna istraživanja na istu temu kako bi se dobili objektivniji i jasniji zaključci o stvarnom utjecaju gospine trave na ispitivane parametre kože., Objectives: To determine whether the analyzed Hypericum perforatum preparation has any kind of skin protecting or regenerating factors on human based model of irritant contact dermatitis caused by Sodium Laurylsulphate (SLS). Material and methods: The base of the study is randomised controlled trial carried out among 14 healthy adult examinees with no skin diseases in their medical histories. The research was conducted during 2019. at The School of Medicine in Split. By using Finn's chambers containing SLS, examinees were deliberately caused irritant contact dermatitis and the analyzed areas were their forearms. During the therapy two preparations were being used, one of them containing active substance (Hypericum perforatum), while the other was mere placebo. Effect of the questioned preparation was the amount of skin hydration, erythema, melanin and transepidermal water loss (TEWL) by using the instrument MPA 6 (Courage+Khazaka, Koln, Germany) with three probes (Mexameter, Corneometer, Tewameter). Results: The examined preparation based on H. perforatum did not show any statistically significant differences indicated on the measured skin parameters (skin hydration, erythema, melanin and transepidermal water loss (TEWL) in contrast to placebo. Conclusions: This research did not prove any effectiveness of Hypericum perforatum on improvement of skin barrier on human model with irritant contact dermatitis, experimentally caused by SLS. It will be necessary to conduct additional researches in order to gain conclusions which could objectively and clearly present the effect of H. perforatum on the examined skin parameters.

Uvod: Čiščenje posode je vsakodnevno opravilo v gospodinjstvu, ki mu velika večina ljudi ne namenja posebne pozornosti. Le malokdo pred uporabo detergenta prebere navodila za uporabo, ampak detergent dozira po lastnem občutku. Tako lahko čistilno sredstvo predoziramo in s tem povečamo količino ostankov na posodi, kar lahko škodljivo vpliva na naše zdravje. Namen: Namen magistrskega dela je določiti koncentracijo ostankov površinsko aktivne snovi natrijevega dodecil sulfata in biocida 1,2-benzizotiazol-3(2H)-ona na posodi po ročnem čiščenju, ugotoviti, ali hrapavost materiala ter globina posode vplivata na koncentracijo ostankov teh dveh kemikalij na posodi ter preveriti, ali imata v izbranih koncentracijah škodljive učinke na testne organizme. Metode dela: Koncentracijo natrijevega dodecil sulfata smo določili s pomočjo spektrofotometra po dodatku metilenskega modrila, medtem ko smo za določanje 1,2-benzizotiazol-3(2H)-ona uporabili tekočinski kromatograf. Po ugotovljenih koncentracijah ostankov obeh kemičnih snovi smo s pomočjo instrumenta LUMIstox izmerili njuno strupenost na luminiscenčne bakterije Vibrio fischeri. Rezultati: Rezultati so pokazali, da na površini krožnikov in lončkov iz lesa ostane več natrijevega dodecil sulfata in 1,2-benzizotiazol-3(2H)-ona kot na površini krožnikov in lončkov iz plastike, porcelana, nerjaveče pločevine in stekla. Ostanki natrijevega dodecil sulfata so bili na površini lončkov v povprečju za 30 % višji od koncentracije ostankov na površini krožnikov, ostanki 1,2-benzizotiazol-3(2H)-ona pa so za 60 % višji pri lončkih. Tako smo potrdili, da je več ostankov na bolj hrapavih površinah in na globljih posodah. S strupenostnim testom smo ugotovili, da koncentracija ostankov natrijevega dodecil sulfata po ročnem čiščenju povzroči od 1,7 % do 2,8 % zaviranja luminiscence pri bakterijah Vibrio fischeri, koncentracija ostankov 1,2-benzizotiazol-3(2H)-ona pa od 7,1 % do 11,5 % zaviranje luminiscence. Največjo strupenost smo zaznali pri koncentraciji obeh snovi, ki je bila v banjici, v kateri smo prali posodo (99 % zaviranje luminiscence). Razprava in zaključek: Zaradi povečanega adsorbiranja ostankov detergenta na površino posode na bolj hrapavih površinah in na globljih posodah predlagamo, da posodo po čiščenju dobro speremo z večjo količino vode, saj bomo s tem odstranili večji delež ostankov čistilnega sredstva z njene površine. Doziranje detergenta je potrebno upoštevati po navodilih proizvajalca, saj edino tako lahko preprečimo škodljive vplive na zdravje človeka. Introduction: Cleaning dishes is a daily activity in every household, which does not receive special attention by most people. Only a few of them actually read the instructions before using the detergent and usually people do not dose it. In such cases, the misusage of the cleaning agent could lead to elevated amounts of residues on the dishes, that could have some harmful effects on our health. Purpose: The purpose of our research was to determine the residual amount of surfactants – sodium dodecyl sulphate and 1,2-benzisothiazol-3(2H)-one on different materials after manual dishwashing. Besides, it was our task also to study the effect of roughness of the material on the amount and toxicity of sodium dodecyl sulphate and 1,2-benzisothiazol-3(2H)-one. Methods: To determine the amount of residue of sodium dodecyl sulphate a spectrophotometric method employing methylene blue was applied, whereas for the 1,2-benzisothiazol-3(2H)-one determination high performance liquid chromatography was used. After determining the residues of both chemicals, the toxicity measurements were done by LUMIstox instrument by measuring the toxicity of residues on luminescent Vibrio fischeri bacteria. Results: The results showed that on the wooden plate and cup there were higher residues of both sodium dodecyl sulphate and 1,2-benzisothiazol-3(2H)-one, compared to other materials like: plastic, porcelain, stainless steel and glass plate and/or cup. The residues of sodium dodecyl sulphate were on average higher by 30 % on cups, compared to plates while residues of 1,2-benzisothiazol-3(2H)-one were higher by 60 %. That proved that the rougher is the material and the deeper is the dish, the more residues remain on them. The amount of remaining sodium dodecyl sulphate on dishes after manual dishwashing caused from 1,7 % to 2,8 % inhibition of luminescence of Vibrio fischeri bacteria, while the amount of 1,2-benzisothiazol-3(2H)-one caused 7,1 % to 11,5 % inhibition. The highest percent of luminescence inhibition (99 %) was detected in the water in which the dishes were washed indicating the synergistic effect of inhibition of both compounds 1,2-benzisothiazol-3(2H)-one and sodium dodecyl sulphate, which are usually discharged in normal household waste waters. Discussion and conclusion: Due to higher detergent and biocide residues in case of rougher materials and deeper dishes, it is suggested that higher volumes of water are used for the final washing procedure, since this will result in removing a larger portion of the cleaning agent from the surface of the dish. The key element is also the dosing of detergent which should be done according to the instructions from the manufacturer. In this way, some side harmful effects on public health from dishwashing could be avoided.

Namen diplomskega dela je bil določiti kritično micelarno koncentracijo (CMC) anionskega surfaktanta natrijev dodecil sulfat (SDS) in kationskega surfaktanta cetildimetilbenzilamonijev klorid (CDBACl) pri standardnih pogojih in proučiti vpliv temperature na vrednost CMC. Kot topilo smo uporabili Milli-Q vodo. Izbrano temperaturno območje je bilo med 283 K in 323 K. Meritve smo izvedli pri sedmih različnih temperaturah v prej omenjenem temperaturnem območju. Pri tem smo uporabili klasično konduktometrično metodo. Na osnovi grafične predstavitve, CMC v odvisnosti od temperature, smo v skladu z literaturo dobili krivuljo v obliki črke U, kar pomeni, da obstaja minimalna vrednost CMC za posamezni surfaktant pri določeni temperaturi. Na koncu smo izračunali še standardne termodinamske količine: stopnjo disociacije proti-iona (β), spremembo standardne entalpije micelizacije (〖ΔH〗_mic^°), spremembo standardne entropije micelizacije (〖ΔS〗_mic^°) in spremembo standardne proste Gibbsove energije (〖ΔG〗_mic^°). To smo naredili v skladu z dvema enačbama, ki se razlikujeta po tem, da ena vpliv temperature na stopnjo disociacije proti-iona β upošteva v celoti, druga pa ta vpliv na β zanemari. Stopnja disociacije proti-iona s temperaturo narašča. Ta ugotovitev velja za izbrano temperaturno območje in za oba izbrana surfaktanta. Standardna prosta Gibbsova energija micelizacijeje negativna (in glede na izbrano temperaturno območje skoraj konstantna), kar pove, da je proces micelizacije spontan proces. Purpose of this study was to determine the critical micelle concentration (CMC) of the anion surfactant named sodium dodecyl sulphate (SDS) and cationic surfactant cetyldimethylbenzilammonium chloride (CDBACl) under standard conditions. Moreover, the effect of the temperature on the CMC value was also investigated. The Milli-Q water was used as a solvent. Measurements were performed at different temperatures within the temperature range of 283 - 323 K. As measurement method the classical conductivity measurements were used. Using graphs CMC as a function of temperature are consistent with the literature given curve U-shaped, which means that there is a minimum value of the CMC for each surfactant at a given temperature. In the end the standard thermodynamic quantity: degree of counterion dissociation (β), standard enthalpy of micellization (〖ΔH〗_mic^°), standard entropy of micellization (〖ΔS〗_mic^°) and the standard Gibbs free energy (〖ΔG〗_mic^°) were calculated. This was done in accordance with the equations, which differ in that one the effect of temperature on the degree of counterion dissociation β takes into consideration as whole the other this effect ignores. It was found that degree of counterion dissociation increased with increasing temperature (within chosen temperature range) for both SDS and CDBACl. The values for standard Gibbs free energy are negative and almost constant within chosen temperature range, which indicates that the micellization process is spontaneous process for presented system.