Thesis (MSc (Chemistry and Polymer Science))--University of Stellenbosch, 2005. / Two cationic polymerizable surfactants (surfmers), (11-acryloyloxyundecyl)dimethyl-(2-hydroxyethyl)ammonium bromide (Ethanol surfmer) and (11-acryloyloxyundecyl)-dimethylethylammonium bromide (Ethyl surfmer) were synthesized and characterized. Characterization was done using, conductivity, Fourier transform infra-red spectroscopy (FT-IR), electrospray mass spectrometry (ESMS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), small angle X-ray scattering (SAXS) and polarized light microscopy with a heating stage. These surfmers and the commercial surfactant cetyltrimethylammonium bromide (CTAB) were used for functionalization of sodium montmorillonite (Na+-MMT), thereby forming organophilic MMT. The functionalization of MMT dispersions was carried out by ion exchange of the sodium ions in Na+-MMT by surfactants in aqueous media. Organophilic MMT clays were then dispersed in styrene and subsequently polymerized by a free radical reaction to yield polystyrene-clay nanocomposites. This in-situ intercalative polymerization process resulted in an exfoliated structure for Ethyl surfmer modified clay, a partially exfoliated structure for Ethanol surfmer modified clay and an intercalated structure for CTAB modified clay. These nanocomposite structures were confirmed by SAXS and transmission electron microscopy (TEM). The nanocomposites exhibited enhanced thermal stability. All the nanocomposites exhibited an inferior storage modulus (GI) at low clay contents relative to polystyrene. At higher clay loadings there was an increase in GI which was dependent on the level of clay dispersion and the clay content. All the nanocomposites showed an increase in glass transition temperature (Tg), regardless of the amount of clay and the level of clay dispersion. There was a shift towards higher temperatures and broadening of the tan δ peak, which was in turn dependent on the amount of clay and level of clay dispersion. Molecular masses of polystyrene-clay nanocomposites were in the range 105 g/mol for bulk polymerization relative to 103 g/mol for solution polymerization as revealed by gel permeation chromatography (GPC).

In title 12, 22, 11 are in subscript. / Thesis (PhD)--Stellenbosch University, 2002. / ENGLISH ABSTRACT: The aim of this study was to test a synthetic protein-free surfactant preparation, LPM-l, with the same chemical composition as commercially available Exosurf (Glaxo Wellcome), but containing in addition, a sugar, trehalose (TRE). Towards this end, a study was designed to firstly test the hypothesis that the true difference in acute physiological effects between a mixture of oppe, tyloxapol, hexadecanol and trehalose (LPM-l), and Exosurf, (Oppe, tyloxapol and hexadecanol) is zero, in a surfactantdeficient animal model. A second study addressed the physiological effects of oppe, hexadecanol, tyloxapol and trehalose (LPM-l) compared to treatment with trehalose (TRE) or saline, in order to determine (1) the contribution of TRE to the mixture of oppe, hexadecanol and tyloxapol, and (2) to assess the effect of the LPM-l surfactant replacement on the epithelial lining fluid composition by means of analysing bronchoalveolar lavage fluid. Thirdly, the effects of TRE and / or calcium were studied on the surface properties of oppe suspensions, by in vitro analysis using the ring detachment method of Du Nouy The in vivo research comprised of two studies, performed in randomised controlled fashion. In the first study, 24 New Zealand White adult rabbits were randomised into 4 groups, while in the second study, 15 animals were randomised into 3 groups. In the first in vivo study, three synthetic surfactants, LPM-l, Exosurf and LPM-2, and a saline group were tested. LPM-l is a new formulation that consists ofa mixture of Df'PC, TRE, hexadecanol and tyloxapol. LPM-2 is a formulation with a composition equivalent to that of commercially available Exosurf, prepared on site. In both studies animals were subjected to repeated lavage with large volumes of warm saline (25 ml/kg) in order to establish surfactant deficiency and acute lung injury. Five minutes after the last lavage, vehicle, i.e. surfactants LPM-l, Exosurf, or LPM-2, or saline, in the first in vivo study, and LPM-l, TRE or saline in the second in vivo study, was instilled, and the course of the animals followed over the next 3 hours. Ventilator settings were standardized before and after lavage. The effects of surfactant treatment on gas exchange (arterial Pa02, oxygenation index (Ol), arterial-alveolar oxygen (a/A) ratio), percentage calculated shunt, and total dynamic respiratory compliance (CRSdyn), and histopathological changes were compared with changes in saline treated controls. Arterial blood gases in 100% oxygen and CRSdynwere measured before and after lavage, at 15 minute intervals for the first 30 min, then at 60, 90, 120, and 180 min after vehicle instillation. Oxygenation improved to a similar extent after LPM-l and Exosurf instillation, surpassing that of LPM-2 or saline. Overall, intratracheal instillation of both Exosurf and LPM-l, rapidly improved the gas exchange and reduced the intrapulmonary shunt, but did not restore the lung to its pre-lavage condition. From the 2nd in vivo study it was evident that trehalose-only, was inefficient as a lung surfactant, failing to improve oxygenation indices or the calculated percentage shunt, or influencing respiratory compliance. The addition of the sugar, trehalose (TRE), to the on-site 'Exosurf mixture (LPM-2) brought the activity of the resultant LPM-l to the same level as that of commercial Exosurf, but failed to raise the activity above that of Exosurf. These physiological improvements were sustained for up to 3 hours. Saline-treated animals had no improvement in gas exchange despite management with variable PIP (to maintain a tidal volume of -1 0 ml / kg) and constant PEEP of 5 cm H20. In-vitro results, obtained by the Ou Nouy tensiometer, showed higher mean ordinate surface tension values for the OPPC-only and DPPC + TRE mixtures, and the slopes of their respective graphs smaller in magnitude than those of the other formulations, suggesting that these formulations had less surface tension-lowering capability than the other surfactants. At 20°C (20 mg / ml DPPC-surfactants) the mean ordinate values of OPPC and OPPC + TRE, 70.13 and 69.47 dyne / cm, respectively, were not significantly different from each other. The mean ordinate values of LPM-l and the formulation containing OPPC + TRE + tyloxapol + CaCh were lower, but similar, as were the values of LPM-2 (on-site Exosurf) and LPM-2 + CaCho Thus, three internally homogeneous subgroups could be identified which differed significantly, namely: DPPC and DPPC + TRE, LPM-2 and LPM-2 + CaCh, and DPPC + TRE + tyloxapol + CaCh and LPM-l. Similar conclusions apply to the ordinate values of the surfactants at 37°C, and to the mean slope values at 20°C, with the exception that the subgroups, LPM-2 and LPM-2 + CaCh, and LPM-l and OPPC + TRE + tyloxapol + CaCh are not so clearly separated. A similar analysis of mean slope values was performed. Here too a significant difference between substances was found, OPPC alone or in combination with TRE, again being significantly different from the other surfactants. The most prominent light microscopy findings of the lungs of animals included general lymphatic dilatation, congestion and lung polymorphonuclear infiltration, with no difference between study groups. Hyaline membranes were present in all surfactant groups, but significantly more so in the saline treated group. In the first in vivo study, the presence of neutrophils in the lung interstitiwn as well as alveoli, was a common finding in all of the study groups towards the end of the study protocol. A significant increase in the BAL-fluid neutrophil count occurred in all animals, concurrent with a significant decrease in the BAL macrophage count. No significant change occurred in the peripheral neutrophil count during the 3-hour study, suggesting recruitment of neutrophils from storage pools. Treatment with synthetic surfactant (LPM -1) did not have a significant effect on modifying the inflammatory response, since there was no significant difference in the BAL-derived cell counts between the LPM-1 and -saline groups. Epithelial damage was a consistent finding in all groups. The damage was more evident by electron microscopy examination and included hydropic changes, most readily observed in the mitochondria. The airspaces of study subjects showed the presence of oedema fluid. This luminal oedema appeared to be more prominent in the control group and LPM-2 (on site 'Exosurf') group. Organellar debris, probably originating from lysis of epithelial cells, was present, despite treatment with synthetic surfactant. The electron microscopical appearance of the epithelial-lined substance ("hyaline membranes") in the present study showed a marked variability within groups as well as within the same case. The majority of cases showed a mix of membrane types with both granular and fibrillar materials present within the same membrane. In some cases there were layering of the membranes into distinct bands. The instillation of LPM-l resulted in the formation of a slightly different type of epithelial lining fluid after lavage, when compared to the prelavage composition. The most pronounced changes occurred within the fatty acids, whilst the phosphatidylcholine values remained unchanged. Palmitic acid concentrations (C16:0) increased significantly, suggesting enrichment of the epithelial lining fluid after instillation of LPM-l. This increase in C16:0 was concurrent with significant decreases in the percentage C16:1, C18:0, and C18:2. In contrast to previous studies, we describe higher levels for phosphatidyldimethylethanolarnine (PEA). An explanation may be that the lipid identified as PEA, was in fact partly phosphatidylglycerol (PG)-a lipid whose accurate identification was precluded for technical reasons. After surfactant instillation, the PC/SM ratio, a reflection of the lecithin / sphingomyelin (LIS), decreased significantly in the TRE-group between the first and final lavage, but remained statistically unchanged in the animals treated with LPM-l or saline. The change in ratio was mainly accounted for by a decrease in BAL-fluid PC content together with a rise in SM content. A poor correlation existed between the BAL-derived PC/SM ratio and indices reflecting oxygenation status (a/A ratio, Ol), as well as the CRSdynat the time of the final lavage. In conclusion, the primary hypothesis was accepted, LPM-l performed similarly to Exosurf in vivo, improving oxygenation, but not CRSdyn.None was clearly superior to the other. Some questions remain. The reason why LPM-l (LPM-2 + TRE) did not behave in a superior manner, in vivo, to Exosurf, is partly unclear. This finding was somewhat surprising since the chemical composition of Exosurf and LPM-2 did not differ, and the addition of TRE to LPM-2 (on-site Exosurf), did improve the in vivo activity of the resultant LPM-l, above that of LPM-2. A possible explanation for observed differences in performance include methodological issues, i.e. the preparation of the on-site formulations, especially that of LPM-2 (on-site Exosurf), may differ from the way in which true commercial Exosurf is prepared. / AFRIKAANSE OPSOMMING: Die doel van die studie was om 'n sintetiese proteïn vrye surfaktant te ontwikkel en die produk te vergelyk met 'n kunsmatige surfaktant reeds in kliniese gebruik. Die bekende uit die literatuur en die onbekende van die produk wat evalueer sou word, lei op tot die samestelling van die nul hipotese van die PhD naamlik dat geen verskil in longfunksie sou gewys word tussen die toetsproduk en reeds gebruikte kommersiële surfaktant nie. Die hipotese was dat 'n suiker (trehalose), in kombinasie met Dipalmitoiel fosfatidielcholine (DPPC), gaswisseling en longfunksies sal verbeter vir 'n long met 'n lae surfaktant konsentrasie. Vir die studie is jong volwasse wit New Zealand konyne gebruik en is hulle met 'n gestandaardiseerde en menslike manier gebruik in eksperimentele werk. Die diere is onder intraveneuse narkose geplaas en verskillende kardiovaskulêre en pulmonologiese aspekte is gemeet. Die long surfaktant is uitgewas deur middel van fisiologiese soutoplossing wat tot liggaam temperatuur verhit is en daarna is die diere prospektief gerandomiseer tot eksperimentele groepe. Met vooraf bepaalde tydsintervalle is die fisiologiese metings herhaal en was die metings toegespits daarop om longmeganiese funksie en gasoordrag vermoë te evalueer. Lig mikroskopiese en elektron mikroskopiese studies is ook op die longe gedoen en verder is brongoalveolêre vloeistof ook ontleed. Die groepe met ondersoek was: I. oppe, heksadekanol, tyloxapol en trehalose (LPM-I). 2. oppe, heksadekanol, tyloxapol (LPM-2 :. LPM-I sonder trehalose). Hierdie is 'n proteïnvrye surfaktant plaaslik berei ( dieselfde samestelling as Exosurf). 3. Exosurf®. (Kommersiële preperaat reeds in gebruik). Hierdie is 'n proteïnvrye sintetiese surfaktant. 4. Trehalose, 'n non-reduserende disakklaried van glukose. Addisioneel is daar ook in vitro studies gedoen waann die oppervlakte spanmngs aktiwiteite van die verskillende surfaktant oplossings vergelyk is. Die statistiese analise is gedoen in samewerking met Prof. J. Maritz wat 'n unieke metode ontwikkel en gepubliseer het om herhalende veranderlikes op 'n statisties verantwoordbare manier te ontleed. In die eerste van die studies, is LPM-I, Exosurf®, fisiologiese soutoplossing en 'n plaaslik bereide "Exosurf" (LPM-2), met 'n chemiese samestelling identies aan dié van kommersiële Exosurf®, evalueer. In 'n tweede studie is die fisologiese effekte van LPM-I vergelyk met trehalose of fisiologiese soutoplossing om die volgende te ondersoek: 1) Die bydrae van trehalose tot 'n mengsel van oppe, heksadekanol en tyloxapol (LPM-2). 2) Die gevolg van LPM-l surfaktant toediening op die konyn se brongo-alveolêre vloeistof samestelling. 'n Derde, in vitro studie, het die oppervlaktespannings-effekte van trehalose en of kalsiumbyvoegings tot DPPC-oplossings gemeet deur middel van die ring metode van Du Nouy, In die eerste in vivo studie verbeter oksigenasie en persentasie longaftakking tot dieselfde mate na LPM-l en Exosurf® toediening en word die hipotese van die proefskrif bevestig. In die breë gesien, is die tydsprofiele van LPM-l en Exosurf® ten opsigte van oksigenasie en persentasie longaftakking statisties betekenisvol beter en van 'n sneller aard, as die tydsprofiele van dieselfde indekse na die toediening van fisiologiese soutoplossing of LPM-2. Die tydsprofiel van dinamiese longvervormbaarheid, na die toediening van LPM-I of Exosurf®, is dieselfde, maar betekenisvol beter as die vervormbaarheid na toediening van LPM-2 of fisiologiese soutoplossing. Alhoewel die oksigenasie indekse in die geval van LPM-l en Exosurf® betekenisvol verbeter oor die studietydperk, vind volkome herstel tot die basislynwaardes (voor spoeling) nie plaas nie. Bykomend, geen van die surfaktante het na toediening enige noemenswaardige verbetering in longvervormbaarheid tot gevolg gehad nie. Die rede vir die swakker vertoning van LPM-2 en Exosurf is onbekend en sal in opvolg studie ondersoek word. In die tweede in vivo studie is dit duidelik dat trehalose op sy eie, 'n oneffektiewe surfaktant is aangesien die preperaat na toediening geen verbetering teweegbring ten opsigte van oksigenasie indekse, persentasie longaftakking, of long-dinamiese vervormbaarheid nie. Die toevoeging van trehalose tot LPM-2, om LPM-l te lewer, neem wel die aktiwiteit van LPM-l tot dieselfde in vivo vlak as dié van kommersiële Exosurf®, maar slaag nie daarim om 'n hoër fisiologiese in vivo aktiwiteit as dié produk te bereik nie. Die diere wat met fisiologiese soutoplossing behandel is toon geen verbetering in enige fisiologiese parameter nie. Die in vitro resultate wat verkry is deur die Du Nouy tensiometer toon hoër gemiddelde ordinaat oppervlaktespannings waardes vir 'n formule wat slegs uit DPPC bestaan, asook vir 'n mengsel van DPPC + trehalose. Die helling van die grafieke van hierdie oplossings is ook kleiner as die van die ander formulas wat daarop dui dat DPPC op sigself, en DPPC + trehalose, weinig vermoë het om oppervlaktespanning te verminder. Daarteenoor verlaag die volgende oplossings die oppervlaktespanning ten opsigte van gedistilleerde water betekenisvol en wel in In konsentrasie afhanklike manier by beide 21°C en 3rc: LMP-I-, LPM-2-, DPPC + trehalose + tyloxapol + CaCf2-, en LPM-2 + CaCf2. Die prominentste ligmikroskopiese bevindinge van die longe van die diere sluit in: Algemene limfvat dilatasie, stuwing, en long neutrofiel infiltrasie. Betreffende hierdie histologiese bevindinge is daar geen verskille aangetoon tussen die groepe nie. Hialienmembrane was teenwoordig in al die groepe, maar betekenisvol meer in die groep wat fisiologiese soutoplossing ontvang as vervangingsterapie. In die tweede in vivo studie is daar 'n betekenisvolle styging in die neutrofiel- en daling in makrofaagtelling, van die brongoalveolêre vloeistof spoeling in al drie die groep aangetoon. Terselfdertyd vind geen noemenswaardige daling in die perifêre (sistematiese) neutrofieltelling plaas nie. Hierdie bevindinge dui daarop dat die brongoalveolêre selveranderinge toegeskryf kan word aan verwerwing van neutrofiele vanuit 'n longstoringspoel eerder as rekrutering vanuit die sistemiese sirkulatoriese poel. Surfaktant (LPM-l), behandeling het geen betekenisvolle vermindering in long inflammasie teweeggebring nie. Epiteelskade was 'n algemene ligmikroskopiese bevinding in al die groepe. Die samestelling van die brongoalveolêre vloeistof verander na installering van LPM-I. Die prominentste verandering word waargeneem in die vetsuur samestelling terwyl die DPPC waardes onveranderd bly. Die vetsuur, palmitiensuur (palmitic acid), (CI6:0), verhoog betekenisvol na toediening van LPM-l. Daarteenoor verminder die konsentrasie van C16:1, C18:0 en C18:2. In kontras met vorige studies, beskryf die huidige studie hoër konsentrasies van fosfatidieletanolamien, moontlik as gevolg van tegniese verskille in die metingsmetodes. 'n Betekenisvolle verlaging in die fosfatidielcholine:sfingomiëlien (PC/SM) verhouding word waargeneem tussen die eerste en die finale longspoeling van die trehalose-groep, terwyl dit onveranderd bly in die diere wat LPM-1 of fisiologiese soutoplossing ontvang.

<p>Razvoj savremenih sistema za ciljanu aplikaciju farmakolo&scaron;ki aktivne supstance zasniva se na postojanju interakcija između funkcionalnih grupa makromolekula i povr&scaron;inski aktivne materije &scaron;to omogućava kontrolisano oslobađanje, smanjenu toksičnost i bolji režim doziranja leka. Prisustvo tenzida, kako se jos povr&scaron;inski aktivne materije nazivaju, u niskim koncentracijima može značajno da izmeni konformaciju makromolekula i viskozitet sistema, i samim tim pro&scaron;iri mogućnosti primene modifikovanjem svojstava. Stoga je poznavanje fizičko-hemijskih osobina vodenih rastvora makromolekul-povr&scaron;inski aktivna materija neophodno radi dobijanja adekvatnog finalnog proizvoda unapređenih osobina uz primenu optimalnih koncentracija pomoćnih supstanci. U radu su prikazani rezultati ispitivanja uticaja natrijum lauril sulfata, predstavnika anjonskih tenzida, odnosno polioksietilen (20) sorbitan monooleata, kao &scaron;iroko kori&scaron;ćenog nejonskog tenzida na fizičko-hemijske osobine vodenih rastvora makromolekula karbomera 940 i ksantan gume. U cilju potpunog razumevanja ovih sistema, čiste komponente su prvo analizirane infracrvenom spektroskopijom primenom Fourierove tranformacije. Pona&scaron;anje karbomera 940 odnosno ksantan gume u prisustvu tenzida, ispitano je kombinacijom različitih tehnika (viskozimetrije, konduktometrije, tenziometrije, spektroskopije, spektrofluorimetrije, skenirajuće elektronske mikroskopije) koje pružaju uporedive rezultate. Određene vrednosti interakcionih parametara, potvrdjuju hipotezu o postojanju međudejstva između karbomera 940/ksantan gume i ispitivanih tenzida i ukazuju da povećanje koncentracije makromolekula u rastvoru uslovljava &scaron;irenje opsega interakcije. Tenzidom indukovane promene konformacije ksantan gume odnosno karbomera 940 potvrđene su i na mikroskopskom nivou. Takođe, rezultati uticaja ispitivanih tenzida na osobine vodenih rastvora sme&scaron;a karbomera 940 i ksantan gume dobijeni su istim tehnikama. Međudejstvom dva različita polimera bez dodatne sinteze na jeftin i brz način mogu se postići željene karakteristike sistema. Na osnovu eksperimentalnih rezultata definisani su matematički modeli primenom metodologije odzivnih povr&scaron;ina i vi&scaron;estruke linearne regresije, čija je validnost statistički potvrđena te se mogu primeniti u optimizaciji i predviđanju fizičko-hemijskih osobina vodenih rastvora analiziranih binarnih sistema.</p> / <p>The possible interactions between polymers and surfactants are of great interest in the development of drug delivery systems, where they improve therapeutic efficiency by the controlled release and reduced toxicity. The addition of even a small amount of surfactant could change the physico-chemical properties of polymer dispersions in terms of viscosity and stability of the system and, consequently, enlarge possibilities for their application. Therefore, understanding the physico-chemical properties of polymer-surfactant aqueous solutions are necessary in order to optimize the formulation of these compounds and consequently to get product with acceptable properties and desired effect. In this thesis the physico-chemical changes of carbomer 940 and xanthan gum influenced by different surfactants were investigated. Widely used anionic surfactant sodium dodecyl sulfate, and nonionic polyoxyethylene (20) sorbitan monooleate were used. In order to completely understand the mechanism of interaction the pure polymers and surfactants were tested by Fourier transform infrared spectrometer. The behaviour of carbomer 940 as well as xanthan gum in the presence of examined surfactants were analysed by the combination of different techniques such as viscometry, conductometry, tensiometry, spectrophotometry, fluorimetry and scanning electron microscopy. The obtained results confirmed the existence of interactions between carbomer 940 / xanthan gum and tested surfactants. Furthermore, the interaction parameters were determined and the polymer saturation points for both surfactants increased with the increase in carbomer 940 and xanthan gum content, respectively. Additionally, the surfactant induced microstructural changes of carbomer 940 as well as xanthan gum were confirmed. Moreover, the physico-chemical properties of the mixture of carbomer 940 and xanthan gum influenced by the addition of anionic and nonionic surfactant were examined by the same techniques. Without additional synthesis the desired characteristics of the system could be achieved by optimizing the interaction between two different polymers. The obtained results were analysed by response surface methodology and multiple linear regression analysis. The defined mathematical models could be used to optimize and predict physico-chemical properties of aqueous solutions of the tested binary systems.</p>

<p>Uloga micela u razvoju farmaceutskih oblika zasniva se na njihovom potencijalu da kao transportni sistemi povećaju bioraspoloživost lekovite supstance i unaprede njen farmakokinetski profil. Micele mogu da modifikuju propustljivost biolo&scaron;kuh membrana, omoguće kontrolisano oslobađanje lekovite supstance iz farmaceutskog oblika, stabilizuju lekovitu supstancu, itd. Kombinovanje različitih surfaktanata kao gradivih jedinica omogućava konstruisanje micela sa poželjnim fizičko-hemijskim karakteristikama. Takođe, me&scaron;ovite micele između čijih gradivnih jedinica postoje sinergističke interakcije se formiraju na nižim koncentracijama surfaktanata u poređenju sa monokomponentnim micelama. U doktorskoj disertaciji je ispitana termodinamička stabilnost binarnih me&scaron;ovitih micela Brij S10 i Brij S20 surfaktanata sa polisorbatom 20, polisorbatom 60 i polisorbatom 80 kao kosurfaktantima. Analiziran je uticaj građe odabranih nejonskih surfaktanata na fizičko-hemijske parametre i stabilnost njihovih me&scaron;ovitih micela. Vrednosti kritične micelarne koncentracije su dobijene spektrofluorimetrijskim merenjima. Da bi se analizirao uticaj temperature na termodinamičku stabilnost micela, merenja su vr&scaron;ena na sledećim temperaturama: 273.15 K, 283.15 K, 293.15 K, 303.15 K i 313.15 K. Rezultati su tumačeni sa aspekta teorije regularnih rastvora (regular solution theory &ndash; RST), uz primenu Porterove jednačine. Na osnovu rezultata istraživanja, predloženi su modeli monokomponentnih i binarnih me&scaron;ovitih micela. Utvrđeno je da u svim analiziranim binarnim me&scaron;ovitim sistemima postoji dodatna entropija. Može se doneti zaključak da pretpostavka RST o isključivo entalpijskoj prirodi dodatne Gibsove energije nije primenljiva na ispitivane binarne sisteme. Utvrđeno je da postojanje razlike u dužini hidrofobnih segmenata monomera dodatno stabilizuje me&scaron;ovitu micelu. Sa porastom temperature, ovaj stabilizacioni efekat entropijskog porekla postaje izraženiji. Prisustvo dvostruke veze u ugljovodoničnom lancu polisorbata 80 doprinosi povećanoj rigidnosti njegovih molekula. Rezultat je smanjena termodinamička stabilnost me&scaron;ovitih micela koje sadrže polisorbat 80 u poređenju sa me&scaron;ovitim micelama koje sadrže njegov zasićeni homolog, polisorbat 60. Utvrđeno je da razlika u dužini polarnih segmenata monomera koji grade me&scaron;ovitu micelu utiče na stepen hidratacije micele, a time i na njenu stabilnost.</p> / <p>The role of the micelles in pharmaceutical formulation lies in their ability to, when used as drug delivery systems, increase the bioavailability of the drug and enhance its pharmacokinetic profile. Micelles may modify the permeability of biomembranes, enable controlled release from drug delivery systems, stabilize the drug, etc. By combining different surfactants as building units it is possible to engineer micelles with favorable physicochemical characteristics. Also, the mixed micelles between whose building units synergistic interactions exist are formed on lower concentrations of surfactants in comparison to single-component micelles. In the doctoral dissertation the thermodynamic stability of binary mixed micelles built of Brij S10 and Brij S20 with polysorbate 20, polysorbate 60 and polysorbate 80 as co-surfactants is examined. The influence of the structure of selected nonionic surfactants on physicochemical parameters and the stability of their mixed micelles is analyzed. Critical micelle concentration values were obtained by spectrofluorimetric measurements. In order to analyze the influence of the temperature on the micelles&rsquo; thermodynamic stability, measurements were conducted on following temperatures: 273.15 K, 283.15 K, 293.15 K, 303.15 K and 313.15 K. Obtained results were studied using regular solution theory (RST) and Porter&rsquo;s equation. Based on the research results, models of both single-component and binary mixed micelles are introduced. It is deduced that in all analyzed binary mixed systems the excess entropy exists. A conclusion can be made that the assumption of RST regarding solely enthalpic nature of the excess Gibbs energy is not applicable to investigated binary systems. The difference in the length of the hydrophobic segments of monomers additionally stabilizes the mixed micelle. With the increase in the temperature, this stabilizing effect of the entropic nature is more noticeable. The existence of the double bond in polysorbate 80 hydrocarbon chain contributes to the increased rigidity of its molecules. As a result, the thermodynamic stability of the mixed micelles containing polysorbate 80 is lesser than the stability of the mixed micelles containing its saturated homologue, polysorbate 60. It is determined that the difference in length of polar segments of mixed micelle monomers affects the micelle hydration and therefore, its stability.</p>

Os surfatantes, moléculas anfipáticas compostas por uma porção polar e outra apolar, constituem um grupo heterogêneo de compostos de superfície ativa. Sua porção polar pode ser formada por peptídeos, ânions ou cátions, por mono, di ou polissacarídeos, enquanto sua porção apolar pode ser formada por estruturas saturadas, insaturadas ou ácidos graxos hidroxilados, ou ainda peptídeos hidrofóbicos. Essas substâncias podem ser sintéticas, obtidas a partir de síntese química, ou produzidas por micro-organismos, principalmente, bactérias e leveduras, passando a ser denominadas biossurfatantes (BS). O BS representa uma alternativa aos tensoativos sintéticos utilizados em diversos seguimentos da indústria devido a sua baixa toxicidade e alta biodegradabilidade, além de aplicabilidade na descontaminação ambiental. Bactérias isoladas em diversos biomas têm sido muito exploradas para produção de BS, enquanto ecossistemas marinhos ainda são pouco explorados, apesar do grande potencial existente. Os micro-organismos marinhos quando expostos a condições extremas de pressão, salinidade e temperatura produzem compostos estáveis e, portanto, úteis em aplicações industriais. O presente trabalho objetivou investigar novos BS produzidos por bactérias de origem marinha capazes de produzir tal substância a partir de fontes de carbono de baixo custo (glicerol, óleo de soja, vaselina e sacarose). Foram analisados 59 isolados bacterianos marinhos, as bactérias selecionadas foram identificadas e a produção do BS foi estudada em escala laboratorial. Após a extração do BS, suas propriedades físico-química como tensão superficial (TS), tensão interfacial (IT) e concentração micelar crítica (CMC) foram determinadas; além disso, foi realizada a caracterização estrutural preliminar e o seu potencial de aplicação para biorremediação de petróleo e como agente emulsificador. Os resultados identificaram a produção de BS por três bactérias marinhas: Arthrobacter defluvii, Brevibacterium luteolum e Gordonia sp. A partir das análises químicas foi possível identificar dois BS lipopepítidicos (A. Defluvii e B. luteolum) e um BS com grupos glicosídicos (Gordonia sp.). O BS produzido por A. defluvii apresentou tensão superficial TS = 34,5 mN m-1; TI = 15 mN m-1; e CMC = 129 mg L-1 crescendo em óleo de soja, B. luteolum TS = 27 mN m-1; TI = 0,84 mN m-1; e CMC = 40 mg L-1 crescendo em vaselina e Gordonia sp. TS = 33 mN m-1; TI = 1,4 mN m-1; e CMC = 85 mg L-1 crescendo em óleo de soja. Os BS estudados apresentaram capacidade de remoção de petróleo de areia contaminada, assim como atividade emulsificante frente a diferentes substâncias ( óleo de soja, vaselina, decano, querosene, hexadecano e gordura vegetal). Os testes de estabilidade realizados para BS produzido por B. luteolum indicaram que: o BS é estável quando submetido a temperaturas até 60oC por 24 h e até 121oC por 20 min; a maior atividade tensoativa para o BS é encontrada em solução com pH entre 6 e 8; e a força iônica não afeta a atividade tensoativa até concentrações salinas abaixo de 16%. Portanto, os três micro-organismos marinhos selecionados foram capazes de produzir compostos com relevante atividade tensoativa utilizando substratos de baixo custo. / The surfactants, amphipathic molecules containing both polar and nonpolar portions, are a heterogeneous group of surface-active compounds. Its polar portion may be composed by peptides, anions or cations, mono, di, or polysaccharides, while its polar portion may contain saturated, unsaturated or hydroxylated fatty acids or hydrophobic peptides. These molecules may be synthetic, derived from chemical synthesis, or produced by microorganisms, mainly bacteria and yeast, and also known as biosurfactants (BS). The BS represent an alternative to synthetic surfactants used in various segments of industry due to their low toxicity and high biodegradability. The major classes of BS include glycolipids, lipopeptides, lipoproteins, phospholipids, fatty acids and polymeric surfactants. Bacteria isolated from different biomes have been heavily exploited for BS production, while marine ecosystems are still poorly explored, despite its great potential. The marine microorganisms when exposed to extremes of pressure, temperature and salinity, produce stable compounds and, therefore, useful in industrial applications. The aim of this study was to investigate new BS produced by marine bacteria capable of producing such molecules growing in low-cost carbon sources (mineral oil, sucrose, soybean oil and glycerol). The selected bacterial isolates were identified and the biosurfactant production was studied in laboratory scale. After extraction of BS their physicochemical properties as surface tension (ST), interfacial tension (IT) and critical micelle concentration (CMC) were determined; preliminary structural characterization evaluated by FTIR and TLC and their potential application in bioremediation of crude oil and as emulsifier was also investigated. The results identified the BS production by three marine bacteria Arthrobacter defluvii, Brevibacterium luteolum and Gordonia sp. Based on the chemical analysis it was possible to identify two lipopeptides BS (A. defluvii and B. luteolum) and a BS with glycosides groups (Gordonia sp.). The BS produced by A. defluvii growing in soybean oil showed ST = 34,5 mNm-1; IT = 15 mNm-1 and CMC = 129 mgL-1; B. luteolum growing in mineral oil showed a ST = 27 mNm-1, IT = 0,84 mNm-1 and CMC = 40 mgL-1 and Gordonia sp. growing in soybean oil showed ST = 33 mNm-1, IT = 1,4 mNm-1 and CMC = 85 mgL-1. The BS obtained exhibited capacity to remove crude oil from contaminated sand as well as emulsifying activity against different hydrophobic substances (soybean oil, mineral oil, decane, kerosene, animal fat and hexadecane). Stability tests carried out to BS produced by B. luteolum indicated that: the BS is stable when submitted to temperatures down to 60° C for 24 h to 121° C for 20 min; the higher activity to the BS is found in solution with pH between 6 and 8; and the ionic strength does not affect the surfactant activity until salt concentrations under 16%. Therefore, the three selected marine micro-organisms were able to produce compounds with significant surfactant activity using low cost substrates.

Os surfatantes, moléculas anfipáticas compostas por uma porção polar e outra apolar, constituem um grupo heterogêneo de compostos de superfície ativa. Sua porção polar pode ser formada por peptídeos, ânions ou cátions, por mono, di ou polissacarídeos, enquanto sua porção apolar pode ser formada por estruturas saturadas, insaturadas ou ácidos graxos hidroxilados, ou ainda peptídeos hidrofóbicos. Essas substâncias podem ser sintéticas, obtidas a partir de síntese química, ou produzidas por micro-organismos, principalmente, bactérias e leveduras, passando a ser denominadas biossurfatantes (BS). O BS representa uma alternativa aos tensoativos sintéticos utilizados em diversos seguimentos da indústria devido a sua baixa toxicidade e alta biodegradabilidade, além de aplicabilidade na descontaminação ambiental. Bactérias isoladas em diversos biomas têm sido muito exploradas para produção de BS, enquanto ecossistemas marinhos ainda são pouco explorados, apesar do grande potencial existente. Os micro-organismos marinhos quando expostos a condições extremas de pressão, salinidade e temperatura produzem compostos estáveis e, portanto, úteis em aplicações industriais. O presente trabalho objetivou investigar novos BS produzidos por bactérias de origem marinha capazes de produzir tal substância a partir de fontes de carbono de baixo custo (glicerol, óleo de soja, vaselina e sacarose). Foram analisados 59 isolados bacterianos marinhos, as bactérias selecionadas foram identificadas e a produção do BS foi estudada em escala laboratorial. Após a extração do BS, suas propriedades físico-química como tensão superficial (TS), tensão interfacial (IT) e concentração micelar crítica (CMC) foram determinadas; além disso, foi realizada a caracterização estrutural preliminar e o seu potencial de aplicação para biorremediação de petróleo e como agente emulsificador. Os resultados identificaram a produção de BS por três bactérias marinhas: Arthrobacter defluvii, Brevibacterium luteolum e Gordonia sp. A partir das análises químicas foi possível identificar dois BS lipopepítidicos (A. Defluvii e B. luteolum) e um BS com grupos glicosídicos (Gordonia sp.). O BS produzido por A. defluvii apresentou tensão superficial TS = 34,5 mN m-1; TI = 15 mN m-1; e CMC = 129 mg L-1 crescendo em óleo de soja, B. luteolum TS = 27 mN m-1; TI = 0,84 mN m-1; e CMC = 40 mg L-1 crescendo em vaselina e Gordonia sp. TS = 33 mN m-1; TI = 1,4 mN m-1; e CMC = 85 mg L-1 crescendo em óleo de soja. Os BS estudados apresentaram capacidade de remoção de petróleo de areia contaminada, assim como atividade emulsificante frente a diferentes substâncias ( óleo de soja, vaselina, decano, querosene, hexadecano e gordura vegetal). Os testes de estabilidade realizados para BS produzido por B. luteolum indicaram que: o BS é estável quando submetido a temperaturas até 60oC por 24 h e até 121oC por 20 min; a maior atividade tensoativa para o BS é encontrada em solução com pH entre 6 e 8; e a força iônica não afeta a atividade tensoativa até concentrações salinas abaixo de 16%. Portanto, os três micro-organismos marinhos selecionados foram capazes de produzir compostos com relevante atividade tensoativa utilizando substratos de baixo custo. / The surfactants, amphipathic molecules containing both polar and nonpolar portions, are a heterogeneous group of surface-active compounds. Its polar portion may be composed by peptides, anions or cations, mono, di, or polysaccharides, while its polar portion may contain saturated, unsaturated or hydroxylated fatty acids or hydrophobic peptides. These molecules may be synthetic, derived from chemical synthesis, or produced by microorganisms, mainly bacteria and yeast, and also known as biosurfactants (BS). The BS represent an alternative to synthetic surfactants used in various segments of industry due to their low toxicity and high biodegradability. The major classes of BS include glycolipids, lipopeptides, lipoproteins, phospholipids, fatty acids and polymeric surfactants. Bacteria isolated from different biomes have been heavily exploited for BS production, while marine ecosystems are still poorly explored, despite its great potential. The marine microorganisms when exposed to extremes of pressure, temperature and salinity, produce stable compounds and, therefore, useful in industrial applications. The aim of this study was to investigate new BS produced by marine bacteria capable of producing such molecules growing in low-cost carbon sources (mineral oil, sucrose, soybean oil and glycerol). The selected bacterial isolates were identified and the biosurfactant production was studied in laboratory scale. After extraction of BS their physicochemical properties as surface tension (ST), interfacial tension (IT) and critical micelle concentration (CMC) were determined; preliminary structural characterization evaluated by FTIR and TLC and their potential application in bioremediation of crude oil and as emulsifier was also investigated. The results identified the BS production by three marine bacteria Arthrobacter defluvii, Brevibacterium luteolum and Gordonia sp. Based on the chemical analysis it was possible to identify two lipopeptides BS (A. defluvii and B. luteolum) and a BS with glycosides groups (Gordonia sp.). The BS produced by A. defluvii growing in soybean oil showed ST = 34,5 mNm-1; IT = 15 mNm-1 and CMC = 129 mgL-1; B. luteolum growing in mineral oil showed a ST = 27 mNm-1, IT = 0,84 mNm-1 and CMC = 40 mgL-1 and Gordonia sp. growing in soybean oil showed ST = 33 mNm-1, IT = 1,4 mNm-1 and CMC = 85 mgL-1. The BS obtained exhibited capacity to remove crude oil from contaminated sand as well as emulsifying activity against different hydrophobic substances (soybean oil, mineral oil, decane, kerosene, animal fat and hexadecane). Stability tests carried out to BS produced by B. luteolum indicated that: the BS is stable when submitted to temperatures down to 60° C for 24 h to 121° C for 20 min; the higher activity to the BS is found in solution with pH between 6 and 8; and the ionic strength does not affect the surfactant activity until salt concentrations under 16%. Therefore, the three selected marine micro-organisms were able to produce compounds with significant surfactant activity using low cost substrates.

Em contraste com a vasta descrição na literatura científica dos biofilmes bacterianos, poucos trabalhos focam o estudo da formação e as estratégias de inibição da constituição do biofilme fúngico. Este trabalho objetiva a caracterização do potencial antifúngico e antibiofilme do sal imidazólico 1-metil-3-octilimidazol cloreto (C16MImCl), e das frações (F70 e F90) purificadas de saponinas mate (Ilex paraguariensis A. st. Hil.), frente a células de biofilme de seis isolados clínicos de Candida tropicalis. A Concentração Inibitória Mínima (CIM) do C16MImCl foi de 0,014μg/mL frente às células planctônicas, ao passo que as Frações de Saponinas da Erva Mate (FSEM) não apresentaram atividade antifúngica. Utilizando o cateter traqueal (CT) como corpo de prova, foi utilizado para avaliar a capacidade de inibição e remoção do biofilme. Avaliou-se também a Concentração Mínima de Erradicação do Biofilme (CMEB) para remoção do biofilme pré-formado pelo método da microplaca. Para a atividade antibiofilme foi observado que o C16MImCl, apresentou melhor resultado quando comparado ao fluconazol. As FSEM também apresentaram atividade antibiofilme quando comparados ao fluconazol, entretanto menores do que o tensoativo sintético Pela análise dos resultados de CMEB, o C16MImCl foi o composto com maior capacidade de erradicar o biofilme pré-formado, na concentração de 0,9 μg/mL (92% a 100% de remoção do biofilme). Os demais compostos testados (fluconazol, FEM e a água) não apresentaram atividade removedora, observando-se valores menores que 80% de remoção. Tanto as concentrações nas quais C16MImCl inibiu as células planctônicas (0,014 μg/mL) como as de biofilme (0,028 -0,225 μg/mL) foram mais baixas que as obtidas pelo fluconazol. Os resultados obtidos demonstram a potencialidade destes tensoativos, principalmente o C16MImCl, que demonstrou baixa toxicidade e provável mecanismo de ação sobre a síntese do ergosterol. Assim, é possível afirmarmos que estes tensoativos representam uma potencial alternativa para o controle químico de fungos leveduriformes, especialmente as ocasionadas por células de biofilme por C. tropicalis. / In contrast to the extensive description in the literature of bacterial biofilms, few works focus on the study of the formation and strategies for inhibiting the formation of fungal biofilms. This work aims to characterize the antifungal potential and antibiofilm the imidazole salt 1 - methyl - 3 - octilimidazol chloride (C16MImCl), and fractions (F70 and F90) purified saponins mate (Ilex paraguariensis A. st. Hil.), against to biofilm cells of six clinical isolates of Candida tropicalis. The Minimum Inhibitory Concentration (MIC) of C16MImCl was 0.014 mg / mL to planktonic cells, whereas the Saponin Fractions of Yerba Mate (SFYM) showed no antifungal activity. Using the tracheal catheter (CT) as a specimen was used to evaluate the ability of the biofilm inhibition and removal. We also assessed the Minimum Biofilm Eradication Concentration (MBEC) to remove the preformed biofilms by the microplate method. For antibiofilm activity was observed that C16MImCl, showed better results when compared to fluconazole. The SFYM also had antibiofilm activity when compared to fluconazole, however smaller than the synthetic surfactant. By analyzing the results MBEC, the compound C16MImCl was capacity to eradicate pre- formed biofilm in a concentration of 0.9 mg / mL (92% to 100% biofilm removal) The other tested compounds (fluconazole, SFYM and water) showed no activity remover, observing less than 80 % removal values. Both concentrations at which they inhibit planktonic cells C16MImCl (0.014 μg/mL) and the biofilm (0.028 -0.225 μg/ml) were lower than those obtained by fluconazole. The results obtained demonstrate the potential of these surfactants, especially C16MImCl, which demonstrated low toxicity and probable mechanism of action on the synthesis of ergosterol. Thus, it is possible to assert that these surfactants are a potential alternative to chemical control of yeasts, especially those caused by biofilm cells of C. tropicalis.

Nanocrystals are an important field of study in the 21st century. Crystallites that are nanometers in size have very different properties from their bulk analogs because quantum mechanical effects become dominant at such small length scales. When a crystallite becomes small enough, the quantum confinement of electrons in the material manifests as a size-dependence of the nanocrystal's properties. Electrical and optical properties such as absorbance, surface plasmon resonance, and photoluminescence are sensitive to the size of the nanocrystal and proffer an array of technological applications for nanocrystals in such fields as biological imaging, laser technology, solar power enhancement, LED modification, chemical sensors, and quantum computation.The synthesis of size-controlled nanocrystals is critical to using nanocrystal in applications for their size-dependent properties. The development of nanocrystal synthesis techniques has been its own entire field of study for two decades or more, and several successes have established novel, utilitarian protocols for the mass-production of nanocrystals with controlled size and very low polydispersity. However, the experimental successes are generally poorly understood and no theoretical framework exists to explain the dynamics of these processes and how to better control or optimize them. It is the goal of this thesis to develop novel theories of nanocrystal synthesis processes to describe these phenomena in theoretical detail and extract meaningful correlations and driving forces that provide the necessary insight to improve the technology and enhance our understanding of nanocrystal growth. Chapter 4, 5 and 6 comprise all the novel research conducted for this thesis, with Chapters 1, 2 and 3 serving as necessary background to understanding the current state of the art. In Chapter 4, we develop a quantitative describe of the process of size focusing, in which a population of polydisperse nanocrystals, which are useless for applications, can be made more monodisperse by the injection of new crystallizable material. We derive mass balance equations that relate the rate of new-material generation to changes in the growth patterns of the nanocrystals. Specifically, we determine that only when the rate of crystal-material production is sustained at a high level can size focusing occur and a monodisperse sample of nanocrystals be produced. Quantitative criteria are provided for how high the rate of production must be, and the quantitative effects on the nanocrystal size distribution function for various magnitudes of the production rate. The effect of the production rate on every facet of the size distribution function is evaluated analytically and confirmed numerically. Furthermore, through comparison of the theory to experimental data, it is determined that a typical nanocrystal synthesis accidentally correlates two variables that are critical to the phenomenon of size focusing. The unknowingly correlated variables have frustrated experimental investigations of the same insights we provided with theory. We recommend a new synthesis protocol that decouples the critical variables, and thus permit the quantitative control of nanocrystal size and polydispersity through theoretical relations, which can also be generalized for the a priori design and optimization of nanocrystal synthesis techniques. In Chapter 5, a theoretical investigation of the growth of surfactant-coated nanocrystals is undertaken. The surfactants create a layer around the nanocrystal that has different transport properties than the bulk solution, and therefore has a strong effect on diffusion-limited growth of nanocrystals. This effect of a surfactant layer is investigated through the lens of the LSW theory of Ostwald ripening as well as through the lens of our own theory of size focusing from Chapter 4. The quantitative effect of a surfactant layer on the various growth processes of spherical nanocrystals is determined, with the result that size focusing can potentially be enhanced by the choice of an appropriate surfactant for a particular nanocrystal material. In addition to the kinetic studies of Chapter 4 and 5, a thermodynamic investigation of surfactant-coated nanocrystals is conducted in Chapter 6, with the goal of understanding the process known as "digestive ripening". In digestive ripening, a population of polydisperse gold nanocrystals is exposed to a strongly binding surfactant, at which point the nanocrystals spontaneously shrink and become highly monodisperse. Different surfactants and different crystal materials can exhibit digestive ripening. Those same materials also have the capacity to be digested further from nanocrystals into molecular clusters that eliminate all crystalline material in favor of surfactant-crystal coordination. The outstanding question is, why does the spontaneous digestive ripening process appear to make large nanocrystals shrink to small nanocrystals, but it does not force small nanocrystals to shrink further to molecular clusters? We construct a full Gibbs free energy model, which we minimize under multiple constraints to obtain quantitative relations for what thermodynamic properties (such as the surfactant binding energy and the crystal-solvent surface energy) govern the existence and size-dependence of a thermodynamically stable nanocrystal. Through our model, we determine that a finite-size nanocrystal is only stable under two possible conditions: either the surfactant-crystal binding is stronger than the crystal-crystal binding and the system contains too few surfactants to form molecular clusters and thus "surfactant-lean" nanocrystals are created, or the surfactantsurfactant intermolecular interactions are sufficiently strong that the nanocrystal core is treated as a swollen micelle in a microemulsion and is stabilized by the surfactant tails' interactions. Quantitative equations are provided that establish what trends and values are expected for experimental results. The results are inconclusive: there is no evidence supporting either conclusion because the available experimental data is insufficient. More accurately, many thermodynamically critical parameters (like the crystal surface energy) are unknown and are practically immeasurable in experimental systems. Speaking generally, the evidence for the surfactant-lean condition is moderately better than the evidence for the microemulsion condition, but in both cases the evidence is insufficient to make a solid conclusion. We therefore use our quantitative results of the thermodynamic investigation to make recommendations to experimentalists as to what trends and what nanocrystal growth processes we expect to observe in either thermodynamic case. While our results are inconclusive in and of themselves, they will be used to highlight the exact thermodynamic driving forces of the experimental systems. We conclude by giving an overview of two new fields of study for theoretical descriptions of nanocrystal growth, specifically the growth of anisotropic nanocrystals and a practical theory for nanocrystal nucleation. Preliminary relations are constructed, with comments on what directions we expect the research to take and how the results would be useful in enhancing our understanding of nanocrystal growth behavior.

Orientador: Valéria de Carvalho Santos Ebinuma / Coorientador: André Gonzaga dos Santos / Banca: Eduardo José Crevelin / Banca: André Moreni Lopes / Banca: Fernanda Perpétua Casciatori / Banca: Alvaro de Baptista Neto / Resumo: Colorantes sintéticos têm sido cada vez mais substituídos pelos colorantes naturais em diversos produtos industriais, pois os últimos apresentam efeitos desejáveis à saúde e podem possuir atividades biológicas. Neste cenário, o fungo filamentoso Talaromyces amestolkiae apresenta-se como uma fonte alternativa de colorantes naturais por não ser micotoxigênico. Assim, técnicas eficientes para a extração e/ou purificação destes biocompostos do meio fermentado são de grande interesse visando sua aplicação industrial. O objetivo deste travalho foi definir a estrutura química do colorante produzido por T. amestolkiae e avaliar Sistemas Micelares de Duas Fases Aquosas (SMDFA) como técnica de extração. Em relação a molécula do colorante, esta foi purificada por técnicas espectrométricas e espectroscópicas e apresentou massa de 542 u, absorção máxima em 544 nm e pertence a classe dos policetídeos. Avaliou-se a estabilidade do colorante vermelho presente no meio fermentado de T. amestolkiae e verificou-se que o mesmo é estável na faixa de temperatura de 25 a 65°C, na presença de altas concentrações do surfactante não iônico TX-114 (1-15% m/m) e dos líquidos iônicos da família dos imidazólios (0,1, 0,5 e 1,0M), porém, a molécula foi estável somente em baixas concentrações de LIs da família das colinas (0,1M). Em relação às partições por SMDFA composto por Triton X-114 e LI como surfactante iônico (família dos imidazólios) ou adjuvante (família das colinas), baixas concentrações de LI, in... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Synthetic colorants have been increasingly replaced by natural ones in several industrial products, since the last have lower adverse health effects and may present biological activities. In this scenario, the filamentous fungus Talaromyces amestolkiae is an alternative source of natural colorants for being non-mycotoxigenic. Thus, efficient techniques for the extraction and/or purification of these biocompounds from the fermented medium are of great interest aiming their industrial application. The objective of this work was to purify natural colorants from the fermented medium of T. amestolkiae by liquidliquid extraction with organic solvents in order to determine the chemical structure of these compounds and to evaluate aqueous micellar two-phase systems (AMTPS) as an alternative extraction technique. In relation to the colorant molecule, it has a mass of 542 u, maximum absorption at 544 nm and structure similar to N-GABA-PP-V molecule of the polyketide class, with an additional glutamic acid chain. In the literature, there are no previous reports of this molecule. The stability of the red colorant present in the fermented medium of T. amestolkiae was evaluated and it was found to be stable in temperature range of 25 to 65 °C, in the presence of high concentration of the non-ionic surfactant TX-114 (1 (0.1, 0.5 and 1.0 M) and the ionic liquids (IL) from imidazolium family (0,1, 0,5 e 1,0 M),however,it is only stable at low concentrations of, IL from the choline family (0,1 M). Regarding the colorant partition by AMTP composed of Triton X-114 and IL as ionic surfactant (imidazolium family) or adjuvant (choline family), low concentrations... (Complete abstract click electronic access below) / Doutor

The purpose of this research was to investigate the effects that aspirin (ASA) and its metabolites, salicylic acid (SA) and acetic acid (AA), have on the delivery of drugs across biological barriers when used in conjunction with electroporation. Electroporation is a technique used to enhance drug delivery across bio-membranes in which a transmembrane potential is induced into cellular membranes, resulting in the creation of aqueous pores that allow molecules to pass through the otherwise impermeable barrier. Aspirin is a widely used drug that has been used for over a century and has been proven relatively safe at normal doses as indicated by the low number of reports of poisoning cases it has been involved in. Components of aspirin are known to soften the cellular membranes by solubilizing the cell's surface proteins. B16F10 murine melanoma cancer cells were used in this investigation and treated with a 120µM buffered solution of calcein, a fluorescent indicator, in which the amount of delivered tracer molecules was measured using fluorescence. Identical concentrations of ASA and SA were investigated (1mM, 5mM, and 10mM) separately, focusing the effects concentration has electroporation delivery. Diluted acetic acid was also investigated at pH values of 6.42, 5.36, and 4.40. The concentration of acetic acid that had the lowest pH and ASA with the highest concentration had the greatest impacts on the augmentation of calcein delivery. Therefore, this demonstrates that aspirin and acetic acid have the potential to improve targeted molecular delivery in combination with electroporation.