Polymer mediated transport of the Hsp90 inhibitor LB76, a polar cyclic peptide, produces an Hsp90 cellular phenotype.

LB76 is a cyclic peptide that shows great promise as a selective heat shock protein 90 (Hsp90) inhibitor. However despite strong binding to and inhibition of Hsp90 in cell lysate its polar structure prevents it from crossing the cell membrane. We have developed a pH responsive polymer nanoparticle that effectively encapsulates LB76 from solution without need for purification.