In the present paper the Euler approach which is generalised for the case of interaction of bodies with deformation is used to describe motions of dimers and unbound fullerenes inside a carbon nanotube. Frequencies and amplitudes of longitudinal vibrations of fullerenes and their dimers inside a CNT are calculated. The conditions under which the energy of rotational motion of a dimer can be transformed into the energy of its translational displacements are determined. This effect has an important application in medicine, specifically, in the sphere of targeted delivery of drugs where a nanotube plays the role of a molecular container.