  We propose a new method to explore a possible departure from the standard
time evolution law for the dark matter density. We looked for a violation of
this law by using a deformed evolution law, given by $\rho_c(z) \propto
(1+z)^{3+\epsilon}$, and then constrain $\epsilon$. The dataset used for this
purpose consists of Strong Gravitational Lensing data obtained from SLOAN Lens
ACS, BOSS Emission-line Lens Survey, Strong Legacy Survey SL2S, and SLACS;
along with galaxy cluster X-ray gas mass fraction measurements obtained using
the Chandra Telescope. Our analyses show that $\epsilon$ is consistent with
zero within 1 $\sigma$ c.l., but the current dataset cannot rule out with high
confidence level interacting models of dark matter and dark energy.
