Comment on “Time-dependent coupled harmonic oscillators” [J. Math. Phys. 53, 052101 (2012)]

Macedo and Guedes [J. Math. Phys. 53, 052101 (2012)] showed recently how to solve a system of coupled harmonic oscillators with time dependent parameters. We show here that the way in which they got rid of the time dependent masses is incorrect and some terms are missing in their transformed Hamiltonian. We also show a correct way of eliminating the time dependent masses from the Hamiltonian.