Sensitive Synchronous Spectrofluorimetric Study of Certain Sunscreens Using Fluorescence Enhancers in Cosmeceutical Formulations

Abstract

Synchronous spectrofluorimetric methods could be successfully adopted for simultaneous determination of Octinoxate (OMC), Avobenzone (AVO), Octyltriazone (OT), and Phenyl benzimidazole sulfonic acid (PBSA) in moisturizing sunscreen lotion, utilizing β-CD as fluorescence enhancer, and determination of Avobenzone (AVO), Homosalate, Tinosorb M and Phenyl benzimidazole sulfonic acid (PBSA) in presence of Octocrylene (OCR) in whitening sunscreen cream, using micellar medium of Sodium Dodecyl Sulfate (SDS) to enhance fluorescence intensity. For first product, zero order synchronous spectrofluorimetric method was used for determination of OMC and AVO, and derivative synchronous spectrofluorimetric technique was utilized for OT and PBSA in quaternary mixture. Linear calibration curves were obtained in a concentration range of 0.5-8 μg mL for OMC and AVO, and in range of 0.05-3 μg mL for OT and 0.001-5 μg mL for PBSA, by measuring the fluorescence at 370, 405, 333.2 and 340.6 nm, respectively. For second product, first derivative synchronous fluorescence method was used for each UV-filter. A linear calibration curves were obtained in a concentration range of 0.5-8 μg mL for AVO, in range of 0.1-8 μg mL for Homosalate, 2-10 μg mL for Tinosorb M and 0.001-5 μg mL for PBSA, by measuring the fluorescence at 409.8, 373, 307.2 and 316.8 nm, respectively. The detection limits are well below the maximum admissible concentration. The proposed methods were validated according to ICH guidelines and successfully applied to determine sunscreens in pure form and in Cosmeceutical formulations. All the results obtained were compared with those of published methods, where no significant difference was observed.