Techniques are provided for targeting a pharmaceutically active compound using, as a carrier, a molecule (or molecules) having greater affinity for a particular site in a living organism's body than for other sites therein. A compound of the formula B-L-A is provided, where B represents the residue of a small synthetic molecule, preferably one that is approved for human use, having a greater affinity for a particular site in a patient's body than for other sites in the patient's body, L represents a direct bond or a linking group, and A represents the residue of a pharmaceutically active compound.