First‐derivative spectroscopic determination of sunscreens in cosmetic formulations

Abstract

Summary Nowadays, cosmetic as well as pharmaceutical forms must undergo many controls, i.e. in-process controls on the finished product and stability testing. The authors suggest using first derivative spectroscopy for active ingredients assay presenting an ultra-violet absorption. It offers the advantage of a direct assay through simple dilution and without active ingredient extraction. Tests were made on classic mixtures of the sunscreens benzimidazol and cinnamate derivative (pair 1), and a mixture of two benzophenones (pair 2). The studied forms were solutions in propylene glycol and commercialized W/O and O/W creams. After analytical method validation for each sunscreen by precision, reproducibility and repeatability studies, the percentages of error of the various assays have been reported in various preparations (solutions or creams). A comparative study between HPLC assay (traditionally used) and the proposed method was carried out. The results show that a highly significant linear correlation exists between the two methods for the four sunscreens (R > 0.992). The speed and simplicity of the first derivative spectrometric method should find applications in routine control or in development of cosmetic or pharmaceutical preparations.

Skin permeation of two different benzophenone derivatives from various vehicles

“…Derivative spectroscopy suggested for spectroscopic determination of sunscreens in routine control and in the development of cosmetic formulations [16] was preferred because of the unsuitability of conventional UV spectroscopy for active ingredient analysis in the skin permeation studies. Water‐soluble proteins and amino acids cause a continuous increase in absorbance towards shorter wavelengths.…”

Ultraviolet and Light Absorption Spectrometry

“…Derivative procedures for vitamin mixtures reported are for pyridoxine hydrochloride and thiamine hydrochloride in tablets (first and third) (179); vitamins B 6 (307 nm, 0.2 µg/mL), B 1 (282.7 nm, 0.46 µg/mL), and B 12 (360.5-374 nm peak to peak, 0.22 µg/mL), uridine 5′-triphosphate (261 nm, 0.2 µg/mL) in injections (second) (180); and sodium salicylate, thiamine hydrochloride, and ascorbic acid in visalicyl tablets (first and second) (181). First-derivative measurements have been used to determine benzimidazole and cinnamate and also benzophenone derivatives in order to characterize sunscreens in cosmetic formulations (182). A direct method (first and second) for evaluating bilirubin, albumin, and oxyhemoglobin in amniotic fluid has been described (183).…”

Validation of HPLC method for the simultaneous and quantitative determination of 12 UV‐filters in cosmetics

“…Many methods have been used in the past to assay multiple sunscreen components in cosmetics. It included ultraviolet‐visible spectrometry (UV‐VIS) [2, 3], high‐performance liquid chromatography (HPLC) [4–6] or even gas chromatography coupled with mass spectrometer (GC‐MS) [7, 8]. However, HPLC with UV detection is the most frequently used analytic method because of its popularity for this type of analysis.…”