2023. Development and validation of an analytical method by HPLC-DAD for determination of caffeine in products based on guarana extracts (Paullinia cupana). Brazilian Journal of Pharmaceutical Sciences. 59, (May 2023), https://doi.org/10.1590/s2175–97902023e22106. DOI:https://doi.org/10.1590/s2175-97902023e22106.