title: Comparison of analytical methods for the quality control of a new formulation containing soy extract and melatonin.
abstract: Three analytical methods have been developed and compared for the quality control of a new formulation (Soymen GN(R) capsules) containing soy extract and melatonin for the treatment of menopausal symptoms. The first method is based on MEKC with diode-array detection, using a mixture of basic carbonate buffer (95%) and methanol (5%), containing 55 mM SDS, as the BGE. The second method is an HPLC method with UV detection at 260 nm. The third method is an HPLC method coupled to amperometric detection which is carried out at an oxidation potential of +0.8 V. In both HPLC systems, the chromatographic separation is obtained on an RP C18 column using a mixture of ACN and an acidic phosphate buffer (25:75 v/v) as the mobile phase. A feasible pretreatment procedure with a methanol/water mixture has been implemented to achieve the quantitative extraction of the main soy isoflavones and of melatonin from the capsules. The results obtained with the three methods are in good agreement with each other and satisfactory in terms of linearity (r(2) >0.9996), precision (RSD <5.4%) and accuracy (recovery >97%). Thus, each of the three analytical methods seems to be suitable for the simultaneous analysis of the main soy isoflavones and melatonin in the new commercial formulation.
authors.affiliation: Laboratory of Pharmaco-Toxicological Analysis, Department of Pharmaceutical Sciences, Faculty of Pharmacy, Alma Mater Studiorum - University of Bologna, Bologna, Italy. mariaaugusta.raggi@unibo.it
authors.forename: Maria Addolorata
authors.initials: MA
authors.lastname: Saracino
authors.forename: Laura
authors.initials: L
authors.lastname: Mercolini
authors.forename: Alessandro
authors.initials: A
authors.lastname: Musenga
authors.forename: Francesca
authors.initials: F
authors.lastname: Bugamelli
authors.forename: Maria Augusta
authors.initials: MA
authors.lastname: Raggi
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002845:Chromatography / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D002853:Chromatography, Liquid / Q000379:methods; D004563:Electrochemistry / Q000379:methods; D007529:Isoflavones / Q000737:chemistry; D007700:Kinetics; D008550:Melatonin / Q000032:analysis / Q000737:chemistry*; D008823:Micelles; D008956:Models, Chemical; D010936:Plant Extracts / Q000737:chemistry*; D011786:Quality Control; D030262:Soybean Proteins / Q000737:chemistry*; D013025:Glycine max / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D007529:Isoflavones; D008823:Micelles; D010936:Plant Extracts; D030262:Soybean Proteins; D008550:Melatonin