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| Author(s): |
Mariana Mandelli de Almeida
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | São Paulo. |
| Institution: | Universidade de São Paulo (USP). Conjunto das Químicas (IQ e FCF) (CQ/DBDCQ) |
| Defense date: | 2008-09-18 |
| Examining board members: |
Érika Rosa Maria Kedor;
Renata Fonseca Vianna Lopez;
Marina Franco Maggi Tavares
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| Advisor: | Érika Rosa Maria Kedor |
| Abstract | |
Vitamin C and vitamin E are natural antioxidants found in many fruits and fresh vegetables, vegetable oils and seed wheat. Cosmetics containing these vitamins in the form of esters have been developed and made available commercially, highlighting the fact that the \"natural\" induces its use in these creams and lotions. Than, it is necessary the validation of analytical methodologies to identify these vitamins in cosmetic preparations, both for the control of product quality and for the safety of consumers. The present work aims the validation of analytical methodologies for determining and quantifying the derivative of ascorbic acid, ascorbyl tetraisopalmitate and the active tocopheryl acetate that are associated in cosmetic formulations. The techniques of UV spectrophotometry and the thermal analysis were used in the characterization of these active ingredients. For the quantification of the actives, analytical methodologies were developed using the following techniques: the UV first-derivative spectrophotometry (UVD), high performance liquid chromatography (HPLC) and capillary electrophoresis (CE). The methodology developed by UV first-derivative spectrophotometry do not showed to be applicable due to the interference of excipients in the formulation. To determine the actives ascorbyl tetraisopalmitate and tocopheryl acetate, a method has been validated by reverse-phase HPLC, using the column Synergi Hidro ® C18, mobile phase methanol :2-propanol (25:75), flow rate 1.0 mL / min and UV detection 222 nm. The samples were extracted without great complexity and the actives could be determined in 3 min and 6 min, for the tocopheryl acetate and ascorbyl tetraisopalmitate respectively. The development of methodology for capillary electrophoresis using the technique of MEEKC (Microemulsion Electrokinetic Chromatography) using the oil-in-water (o/w) microemulsion do not showed to be suitable for determination of active ingredients in the study, and that the work will attempt the prospects of using MEEKC the water-in-oil (w/o) microemulsion. (AU) | |