Investigation of Different Analytical Techniques forthe Quantitation of Some Selected UV-Blockers in Cosmetic Products

Abstract

This thesis is concerned with the development of different simple, sensitive and specific methods of analysis for determination of some UV-filters used in sunscreen formulations which protect the skin from the harmful effects of UV light (skin cancer and photo-damage and wrinkling); namely Octinoxate, Oxybenzone, Octocrylene, Avobenzone and 4-methyl Benzylidene Camphor either in bulk powder or in their formulations and in rat epidermal membrane.

Also, stability-indicating methods were adopted quantifying the pure UV-filters in presence of their acid, alkaline and oxidative degradates. Establishment of the stability indicating methods is of great pharmaceutical value, because any degradation occurring at normal storage conditions can be determined.

This thesis includes six parts:

Part one: Introduction and Literature Review

This part is divided into two sections:

Section A: General Introduction

This section comprises brief data about sunburn, UV-light and UV-filters, their classes, and their stability.

Section B: Literature Review

In this section, structures, physicochemical properties and assay methods, reported in the literatures for the studied UV-filters, are stated.

Part two:High Performance Liquid Chromatographic Methods

This part is divided into three sections

Section A: HPLC Method for Simultaneous Determination of AVO and MBC in Sunscreen Formulations and Rat Skin Tissue.

This section comprises HPLC method for quantitative determination of AVO and MBC. The optimum conditions for separation process were determined. The developed chromatographic method utilized Agilent 5 HC.C18 (2) 250x4.6 mm column as stationary phase, “Methanol: ACN” (70:30, v/v) as a mobile phase with effluent flow rate 1.20 mL.min-1and UV-detection at 320.00 nm.

Section B:Stability-Indicating HPLC Method for Determination of OMC, OXY and OCR in Presence of Their ‘Acid, Alkaline and Oxidative-Degradates’ and their Structure Elucidation.

This section comprises HPLC method for quantitative determination of OMC, OXY and OCR in presence of their acid, alkaline and oxidative-degradates. The optimum conditions for separation process were determined. The developed chromatographic method utilized Agilent 5 HC.C18 (2) 250x4.6 mm column as stationary phase, “Methanol: ACN: water” (70:20:10, v/v) as a mobile phase with effluent flow rate 1.20 mL.min-1and UV-detection at 228.00 nm. Also, LC-MS technique was adopted for the structure elucidation of their degradates.