Synthetic Polymers as Targetable Carriers for Drugs

The cellular phenomena of pinocytosis and lysosomal digestion are described, with particular emphasis on the handling of soluble macromolecules by living cells. A drug delivery system based on poly(hydroxypropylmethacrylamide) conjugated to drug analogues by oligopeptide sequences has been evaluated. The conjugates, which are stable in the bloodstream, are captured by pinocvtosis and taken to the lysosomal compartment of cells. There theoligopeptide sequences are hydrolysed by the lysosomal enzymes and the drug analogues released. Targeting has been demonstrated by incorporation into the polymer of side-chains bearing moieties that lead to non-specific or cellspecific adsorptive pinocytosis.