Titanov dioksid (Titanium dioxide)

Ars Cosmetica Forum SPLOŠNE TEME O KOZMETIKI SESTAVINE V KOZMETIKI Titanov dioksid (Titanium dioxide)

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  • #3595
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    Nina
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    TITANOV DIOKSID spada med anorganske/mineralne/fizikalne sončne filtre. Večino žarkov odbija nekaj pa jih tudi absorbira in sprosti v obliki toplote. V kozmetiki se uporablja mikroniziran titanov dioksid (delci manjši od 2 μm), kar izboljša mazljivost, občutek na koži in zmanjša ostanek bele barve na koži.
    Največja dovoljena koncentracija v izdelkih za sončenje je 25%, isto velja za cinkov oksid. Oba spadata med širokopasovne filtre- UVA in UVB zaščita. Oba sta inertna, varna in ne povzročata alergij (vsaj v veliki večini ne; načeloma lahko vsak filter povzroča alergije in senzibilizacije).
    Na tržišču velikokrat oglašujejo izdelke z mineralnimi filtri kot “popolnoma naravne”, “brez kemije”..kar je v bistvu zavajanje potrošnikov, saj je dejstvo, da tudi mineralni filtri pred dodajanjem v formulacijo kozmetičnega izdelka gredo skozi kemijske in tehnološke procese.

    #23851
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    Nina
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    ČLANEK: Primerjava biološke aktivnosti med dvema različnima oblikama (glede na velikost delcev) titanovega dioksida
    UGOTOVITEV: Titanov dioksid v obliki manjših delcev izraža večjo biološko aktivnost, med drugim v večjem obsegu sproži znotrajcelično nastajanje reaktivnih kisikovih spojin (radikalov)

    Comparison of the biological activity between ultrafine and fine titanium dioxide particles in RAW 264.7 cells associated with oxidative stress.
    Kang JL, Moon C, Lee HS, Lee HW, Park EM, Kim HS, Castranova V.
    Department of Physiology, Ewha Medical Research Center, School of Medicine, Ewha Womans University, Seoul, South Korea. jihee@ewha.ac.kr
    J Toxicol Environ Health A. 2008;71(8):478-85.
    vir: http://www.pubmed.gov

    Ultrafine or fine titanium dioxide (TiO(2)) particles are widely used in the production of white pigments, for sunscreens, and in cleanup techniques. However, currently knowledge is deficient concerning cellular responses to these particles.
    The study evaluated and compared the biological activity of ultrafine and fine TiO(2) particles in RAW 264.7 macrophages according to an oxidative stress paradigm. In vitro exposure of macrophages to ultrafine or fine TiO(2) in the range of 0.5-200 microg/ml did not significantly alter cell viability. However, ultrafine TiO(2) enhanced intracellular generation of reactive oxygen species (ROS) to a greater extent than fine TiO(2) at each exposure concentration. Ultrafine TiO(2) induced ERK1/2 activation in a concentration-dependent manner, while the fine TiO(2)-induced changes were minimal. Phosphorylation of ERK1/2 occurred following 10 min exposure to higher concentrations of ultrafine TiO(2) (> or = 25 microg/ml). Similarly, ultrafine TiO(2) exposure significantly enhanced tumor necrosis factor (TNF)-alpha and macrophage inflammatory protein (MIP)-2 secretion in a concentration-dependent manner, and its potency was higher than fine TiO(2). These findings suggest that when exposure concentration is based upon equivalent mass, ultrafine TiO(2) exerts greater biological activity as measured by ROS generation, ERK 1/2 activation, and proinflammatory mediator secretion in RAW 264.7 macrophages than fine TiO(2).

    Ultrafine titanium dioxide: velikost delcev 10-50 nm, se uporablja v izdelkih za sončenje

    #23852
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    Nina
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    ČLANEK: Nanotehnologija (TiO2 in ZnO)-kozmetika-koža: obstaja v tej navezi potencialna nevarnost za zdravje?
    POVZETEK: Nanodelci titanovega dioksida in cinkovega oksida ne prodirajo v kožo in niso potencialno nevarni za zdravje

    Nanotechnology, cosmetics and the skin: is there a health risk?
    Nohynek GJ, Dufour EK, Roberts MS.
    L’Oréal Research and Development, Worldwide Safety Department, Asnières, France. gnohynec@rd.loreal.com
    Skin Pharmacol Physiol. 2008;21(3):136-49. Epub 2008 Jun 3.
    http://www.pubmed.gov

    Cosmetic formulations may contain nano-emulsions and microscopic vesicles consisting of traditional cosmetic materials, although it is uncertain whether they should be qualified as actual nanomaterials. Vesicle materials do not penetrate into living human skin. Vesicle formulations may enhance or reduce skin absorption of ingredients, albeit at a limited scale. Sunscreens contain TiO2 or ZnO nanoparticles (NP), which are efficient UV filters. A number of studies suggest that insoluble NP do not penetrate into or through human skin. The results of in vivo toxicity tests showed that TiO2 and ZnO NP are non-toxic. In vitro and in vivo cytotoxicity, genotoxicity, photogenotoxicity, acute toxicity, sensitisation and ecotoxicology studies on TiO2 NP found no difference in the safety profile of micro- or nano-sized materials, all of which were non-toxic. Although some in vitro investigations on TiO2 particles reported cell uptake, oxidative cell damage or genotoxicity, these results may be secondary to phagocytosis of cells exposed to excessive particle concentrations. Studies on wear debris nano- and microparticles support the traditional view that toxicity of small particles is related to their chemistry, rather than their particle size. There is little evidence supporting a general rule that adverse effects of particles on the skin or other tissues increase with smaller particle size, or produce novel toxicities relative to those of larger particles. Overall, the current evidence suggests that nano-sized cosmetic or sunscreen ingredients pose no potential risk to human health, whereas their use in sunscreens has large benefits, such as the protection of human skin against skin cancer.
    (c) 2008 S. Karger AG, Basel.

    #23853
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    Nina
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    Če povzamem:

    V želji po čimboljših senzoričnih lastnosti izdelkov za sončenje in boljši zaščiti pred sončnimi žarki, so se v kozmetiki začeli uporabljati vedno manjši delci titanovega dioksida, ki imajo med drugim prednosti v boljši mazljivosti, občutku na koži, manjšemu ostanku bele barve na koži (titanov dioksid je namreč mineralni pigment bele barve)..
    Nekatere in vitro raziskave kažejo, da bi ultra majhni delci (nanodelci) titanovega dioksida lahko imeli določene neželene posledice. Na drugi strani pa so rezultati in vivo raziskav pokazali, da nanodelci titanovega dioksida in cinkovega oksida ne penetrirajo v kožo in niso toksični.

    Ker zaenkrat titanov dioksid še vedno velja za varen in stabilen filter, ki je hkrati še širokopasoven UVA IN UVB filter, je moje mnenje, da je njegova uporaba smiselna, vendar v kombinaciji še s kakšnim organskim/kemijskim filtrom- s takšno kombinacijo dobimo boljšo zaščito hkrati pa lahko zaradi kombinacije različnih filtrov v izdelke za sončenje dodajo manjše koncentracije le-teh brez da bi zmanjšali učinkovitost.

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