  We report on the using of torsion-rotational transitions in the CH3OH and
(13)CH3OH molecules to evaluate possible variations of the physical constant
mu=m_e/m_p - the electron-to-proton mass ratio - from spectral observations of
emission lines detected in the microwave range towards the dense molecular
cloud Orion-KL. An estimate of the upper limit on the relative changes in mu is
obtained by two independent ways - with (13)CH3OH lines and with the
combination of (13)CH3OH and CH3OH lines. The calculated upper limit Delta
mu/mu < 1.1*10^{-8} (1 sigma) is in line with the most stringent constraints on
the variability of fundamental physical constants established by other
astrophysical methods.
