Ugotavljanje vsebnosti vitamina C v kozmetičnih izdelkih

Kozar, Laura (author), Roškar, Robert (mentor), Temova Rakuša, Žane (co-mentor)

Vitamin C se uporablja kot aktivna sestavina v kozmetičnih izdelkih za posvetlitev kože in nego mastno-aknaste kože ter nego zrele kože. Najpogosteje se uporablja v obliki askorbinske kisline in njenih derivatov askorbil palmitata, askorbil tetraizopalmitata, askorbil glukozida, etilirane askorbinske kisline, natrijevega askorbil fosfata in magnezijevega askorbil fosfata. Osrednji cilj diplomske naloge je bil vrednotenje vitamina C in njegovih derivatov z vidika vsebnosti in stabilnosti v različnih kozmetičnih izdelkih z metodo tekočinske kromatografije visoke ločljivosti. Izbrali smo 10 kozmetičnih izdelkov različnih oblik, ki so na ovojnini navajali prisotnost askorbinske kisline in nekaterih derivatov-askorbil fosfata in askorbil palmitata. Nekateri izdelki pa so tudi kvantitativno navajali vsebnost vitamina C. Za vrednotenje vitamina C smo najprej ustrezno ovrednotili predhodno razvito HPLC-UV analizno metodo. Nato smo glede na sestavo izdelkov razvili in optimizirali enostavne postopke priprave vzorcev. V izdelkih smo najprej ugotavljali prisotnost in vsebnost navedene oblike vitamina C. Pri izdelkih, ki so imeli navedeno vsebnost vitamina C, pa smo preverjali, ali se le-ta sklada z eksperimentalno ugotovljeno. Ugotovili smo, da se pri devetih izdelkih navedene oblike vitamina C skladajo z eksperimentalno ugotovljenimi. Pri enem izdelku pa nismo zaznali askorbinske kisline in askorbil palmitata, čeprav sta navedena med sestavinami na ovojnini izdelka. Pri vseh sedmih testiranih izdelkih, ki kvantitativno navajajo vsebnost vitamina C, se je ta ujemala z eksperimentalno ugotovljeno vsebnostjo. Med vsebnostjo vitamina C in ceno izdelka nismo našli neposredne povezave. Zaradi splošno znane nestabilnosti vitamina C smo preverili tudi njegovo stabilnost v testiranih kozmetičnih izdelkih. Stabilnost askorbinske kisline in askorbil fosfata smo v izbranih izdelkih vrednotili z dolgoročnimi in pospešenimi testi stabilnosti znotraj enega meseca. Pri dolgoročnem testu smo zaznali le manjši upad vsebnosti vitamina C v vseh testiranih izdelkih. Pri pospešenem testu pa je bil upad znatnejši. S tem smo potrdili, da je vitamin C občutljiv na povišano temperaturo, če izdelek ni ustrezno stabilnostno formuliran oziroma nima dodanih sestavin, ki bi ščitile vitamin C pred procesi nestabilnosti.

• Language: Slovenian
• Keywords: vitamin C, kozmetični izdelki, vsebnost, stabilnost
• Work type: Bachelor thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2020
• PID: 20.500.12556/RUL-119478
• Publication date in RUL: 09.09.2020

Secondary language

• Language: English
• Title: Determination of vitamin C content in cosmetic products

Abstract

Vitamin C is common active ingredient in cosmetics as a depigmenting agent and in treatment of oily and acne-prone skin. It is mostly used in the form of ascorbic acid and its derivatives ascorbyl palmitate, ascorbyl tetraisopalmitate, ascorbyl glucoside, ethylated ascorbic acid, sodium ascorbyl phosphate and magnesium ascorbyl phosphate. The main objective of this diploma thesis was to evaluate vitamin C and its derivatives in terms of content and stability determination in commercial cosmetic products. Therefore, 10 cosmetic products in various forms were purchased locally. Ascorbic acid and some derivatives ascorbyl phosphate and ascorbyl palmitate were either stated as ingredients or were quantitatively defined. These were evaluated by a previously developed high-performance liquid chromatography method, which was initially validated. Based on the products compositions, we developed and optimized proper extraction procedures, which were applied to determine the presence and content of vitamin C and its derivatives. The obtained results were compared to the label claims. In nine of the ten tested products, the determined vitamin C forms were consistent with the ones listed on the packaging. In one product, ascorbic acid and ascorbyl palmitate, which were listed among the ingredients, were not detected. Vitamin C content was quantitatively defined in 7 tested products and was consistent with the experimentally determined content in all products. Because of the known vitamin C instability, we evaluated its stability in the tested cosmetic products. The stability of ascorbic acid and ascorbyl phosphate was evaluated in selected products by long-term and accelerated stability tests within one month. At long-term stability test, only a small decrease in vitamin C content was detected in all tested products. The decrease was more pronounced at accelerated stability test. This confirmed that vitamin C is susceptible to degradation at elevated temperatures in products, which are not properly formulated or have no added ingredients that stabilize vitamin C.

• Keywords: vitamin C, cosmetic products, content, stability