Synthesis of Well-Defined pH-Sensitive Poly(N-vinylpyrrolidone)-b-Poly(4- vinylpyridine) Copolymers and Their Drug Delivery Application

Abstract

Drug delivery of anticancer drugs using drug loaded nanocarrier has been widely used because of minimizing side effects resulting from their direct injection. Since tumor tissue has lower pH than normal tissue, that why the use of pHresponsiveness blocks copolymer micelles are great and smart material for nanocarrier in drug delivery. So, we synthesized the new poly(N-vinylpyrrolidone)-block-poly(4- vinylpyridine) amphiphilic diblock copolymers (PNVP-b-P4VP), via combination of reversible addition fragmentation chain transfer (RAFT) and atom transfer radical polymerization (ATRP) using difunctional chloroamide-xanthate iniferter, and studies micelles formation in water. Note that PNVP shows much higher water solubility and high stability against various environments (e.g., lypoprotectivity, cryoprotectivity) than commonly used hydrophilic poly(ethylene glycol) (PEG). The micelle formation in water with cores consisting of P4VP and shells with PNVP was investigated by dynamic light scattering (DLS), atomic force microscopy (AFM), and scanning electron microscopy (SEM). After doxorubicin was loaded into P4VP cores, we performed drug release, at various pHs. We found drug release only in pH < 6.8, confirming potential of pH-sensitive micellar drug delivery.