Research on Determination and Stability of EGCG in Cosmetics
A method for the detection of EGCG content by high-performance liquid chromatography(HPLC)was established.ZORBAX Extend-C18(250 mm×4.6 mm,5 μm)Column was used for gradient elution with methanol(phase A)-0.05%trifluoroacetic acid aqueous solution(phase B)as mobile phase.The elution time is 35 min.The column temperature is 35℃.The flow rate is 1.0 mL/min.The injection volume is 10 μL,and the detection wavelength is 280 nm.Under these chromatographic conditions,the linearity range of EGCG is 10～1 000 mg/L,R2=0.999 6,precision(n=6)RSD was 1.25%,repeatability(n=6)RSD was 0.84%,and stability RSD was 0.61%.The average recovery rate of EGCG is 92.27%.The RSD is 1.18%.This method is conducive to the quality control of EGCG in different dosage forms and raw materials of cosmetics.The stability of cosmetics with different dosage forms of EGCG raw materials was investigated,and the results showed that the stability of EGCG was better than that of EGCG phospholipid complex,but the EGCG content decreased greatly with the passage of time.In addition,temperature has a great influence on the EGCG content,and low temperature storage is more conducive to the content stability.In order to ensure the efficacy of cosmetic products,EGCG should be added in sufficient quantities as raw materials.
tea polyphenolsEGCGhigh performance liquid chromatographycosmeticsstability study
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