PEG based anti-cancer drug conjugated prodrug micelles for the delivery of anti-cancer agents

Due to the high cost and uncertain success of new drug development, tremendous effort is devoted to increasing the efficacy of established anti-cancer drugs. Development of polymer prodrug conjugates has evolved recently in the nano-medicine field for cancer diagnosis and treatment. The major advantage of using polymer drug conjugates is that the chemical and physical properties of polymers can be tuned to increase the efficacy and to reduce the toxicity of the drug. The stimuli responsiveness provides the release of the prodrug in a controlled manner which avoids undesired side effects, organ damage, and toxicity caused by the fluctuations associated with periodic administration. A large number of anti-cancer drug polymer conjugates have been studied for cancer therapy due to their promising clinical applications in chemotherapy. In this paper, poly(ethylene glycol) (PEG) based anti-cancer drug conjugates will be discussed followed by a review of different types of PEG-b-poly(epsilon-caprolactone) (PEG-b-PCL) copolymer drug conjugates and histone deacetylase inhibitor polymer conjugates as novel therapeutics. The pH sensitive release of prodrugs will be discussed for polymer prodrug conjugates that are currently under investigation.