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First‐derivative spectroscopic determination of sunscreens in cosmetic formulations
Author(s) -
MICHAUD P.,
SOTO P.,
ROY T. LE,
RODRIGUEZ F.
Publication year - 1994
Publication title -
international journal of cosmetic science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 62
eISSN - 1468-2494
pISSN - 0142-5463
DOI - 10.1111/j.1467-2494.1994.tb00087.x
Subject(s) - repeatability , derivative (finance) , active ingredient , chemistry , chromatography , ingredient , reproducibility , dilution , physics , pharmacology , medicine , food science , financial economics , economics , thermodynamics
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.