VALIDACIÓN DE UN MÉTODO DE CROMATOGRAFÍA LÍQUIDA DE ALTA RESOLUCIÓN (CLAR), EMPLEANDO COMO MARCADOR LA EPIGALOCATEQUINGALATO,PARA EVALUAR LA CALIDAD DE UNA FORMULACIÓN SEMISÓLIDA OBTENIDA DE Rhizophora mangle L.

With the aim of establishing a chemical marker of polyphenols and validating a HPLC method, for assessing the quality of semisolid products, obtained from Rhizophora mangle L aqueous bark extract, four methods for extracting the analyte from the sample, were compared. The variant using ethyl acetate and its direct application to the chromatograph was the most effective. The epigalocatequingallate (EGCG) was selected as a marker among other polyphenols identified. The semisolid product, under oxidative stress conditions, shows a decline and changes in the chromatographic profile. Performance parameters show a linear method in the range of 1-15 ug / mL with a regression coefficient of 0.999, and have a limit of detection and quantification of 2.5 ug / mL and 5.0 ug / mL, respectively. The recovered from EGCG in a reagent blank was 89 ± 9%, while, added to the product, was 60.1 ± 3.52 ug / g, due to interactions with the matrix. Repeatability studies (RSD) achieved for the standard and the sample were 1.29 and 10.67%, respectively. The reproducibility, estimated from Horwitz equation, showed a variation between 8-11%. EGCG assessment in product lots showed values ranging between 36.5 and 66.7 ug/ g. The analytical procedure developed, using EGCG as a chemical marker, proved to be reliable in the quality control of semi-solid products.