Fig. 6.
Structures of PK1 and PK2, first HPMA copolymers evaluated in clinical trials [68]. Conjugate PK1 contains doxorubicin bound to HPMA copolymer via a tetrapeptide sequence stable in the blood stream but susceptible to enzymatically catalyzed hydrolysis in the lysosomes. Conjugate PK2 contains in addition side-chains terminated in N-acylated galactosamine complementary to the asialoglycoprotein receptor on hepatocytes.
