HPLC Method with Solid-Phase Extraction for Determination of (R)- and (S)-Ketoprofen in Plasma without Caffeine Interference: Application to Pharmacokinetic Studies in Rats

Francisco Javier Lopez-Munoz1,2, Nancy Vara Gama1, Olivia Soria-Arteche1, Marcela Hurtado y de la Pena1, Adriana Miriam Dominguez-Ramirez1 and Jose Raul Medina Lopez1* Departamento Sistemas Biologicos UAM-Xochimilco, Calzada del Hueso 1100, Colonia Villa Quietud, Mexico, D.F., CP 04960, Mexico, and Departamento Farmacobiologia, Cinvestav-Sede Sur, Calzada de los Tenorios 235, Colonia Granjas Coapa, Mexico, D.F., CP 14330, Mexico