Validation of an LC-ESI-MS/MS method for the quantitation of phosphodiesterase-5 inhibitors and their main metabolites in rat serum and brain tissue samples

1. Unceta, N.
2. Echeazarra, L.
3. Montaña, M.
4. Sallés, J.
5. Gómez-Caballero, A.
6. Goicolea, M.A.
7. Barrio, R.J.