The present invention relates to improvements in the field of drug delivery.More particularly, the invention relates to a non-invasive and flexible methodand carrier for transporting a compound or drug across the blood-brain barrierof an individual. In particular the present invention relates to a carrier fortransporting an agent attached thereto across a blood-brain barrier, whereinthe carrier is able to cross the blood-brain barrier after attachment to theagent and thereby transport the agent across the blood-brain barrier. Thepresent invention relates to improvements in the field of drug delivery. Moreparticularly, the invention relates to a non-invasive and flexible method andcarrier for transporting a compound or drug across the blood-brain barrier ofan individual. In particular the present invention relates to a carrier fortransporting an agent attached thereto across a blood-brain barrier, whereinthe carrier is able to cross the blood-brain barrier after attachment to theagent and thereby transport the agent across the blood-brain barrier.