Method development and method validation of guaifenesin and dextromethorphan by RP-HPLC. International Journal of Research In Pharmaceutical Chemistry and Analysis, [S. l.], v. 1, n. 1, p. 18–24, 2018. Disponível em: https://rubatosis.org/journals/index.php/ijrpca/article/view/93.. Acesso em: 6 sep. 2025.