Objective: The purpose of this study was to develop a low-cost, yet sensitive and precise UHPLC method for the quantitative determination of ostarine from dietary supplements (DS) for athletes. The analytical performance of the method was verified on a DS legally acquired from a specialized website for athletes. The uniformity of mass and content of the ostarine DS was also verified.
Methods: For the quantitative determination of ostarine a UHPLC method was developed and validated. The separation was performed using a reversed-phase C18 column, using a mixture of 75% methanol: 25% formic acid 0.1% in isocratic elution, at a flow rate of 0.5 ml/min. The uniformity of mass and content of DS was performed following the methodology described in the European Pharmacopoeia 7th Edition.
Results: The validated method was specific and linear on the concentration range of 1-25 µg/ml and was precise and accurate at all concentration levels, according to the official guidelines for validating analytical methods. An average mass of 510 mg content was obtained for the ostarine capsules, with an RSD of 2.41%. Regarding the uniformity of the content, an average of 4.65 mg ostarine/capsule was obtained with an RSD of 1.05%.
Conclusions: The developed UHPLC method was suitable, rapid, sensitive and allowed quantitative determination of active substance content in a DS with ostarine (92.91% ostarine/capsule from 5 mg ostarine/capsule declared by the manufacturer).