Provided is the use of a composition containing nanoparticles comprising a macrolide and an albumin in the manufacture of a medicament for the treatment of vascular fibrosis and/or to widen a blood vessel, wherein the medicament is to be injected into the blood vessel wall or the tissue surrounding the blood vessel wall. The macrolide may be rapamycin. The albumin may be human serum albumin. Further provided is a catheter comprising the composition and which has a deployable needle.
