Stability and solubility of trans-resveratrol are strongly influenced by pH and temperature

Recently trans-resveratrol (trans-RSV) has received great attention due to its prophylactic and therapeutic properties. Its limited bioavailability provides compelling evidence of the need for more suitable formulations in order to attain better clinical effectiveness. Some physicochemical properties of trans-RSV are still unknown or research findings are contradictory. Therefore, this paper presents newly determined trans-RSV solubility and stability at various pH and temperatures, and the importance of such data for the studies of novel trans-RSV-loaded nanofibers. In acidic pH trans-RSV was stable, whereas its degradation started to increase exponentially above pH 6.8. Consequently, it is worthwhile to note that special consideration has to be dedicated to long dissolution testing or biological assays on cell lines in order to obtain relevant data. Measurements were done by validated UV/VIS spectroscopy, HPLC, and newly developed UPLC methods. Specificity was confirmed for HPLC and UPLC method, whereas UV/VIS spectroscopy resulted in false higher trans-RSV concentrations in conditions under which it was not stable (alkaline pH, light, increased temperature). The study is of interest because it draws attention to the importance of careful selected experimental conditions, their influence on the trans-RSV stability and the implications this has for formulation development, storage, and maintenance of therapeutic doses.