Abstract:
Block copolymers (BCPs) are a particular type of copolymers, wherein the chemically distinctive monomer units are assembled in discrete blocks along the polymer chain. BCPs are very important class of materials because of their ability to be organized into nanostructures and their uses in diverse applications such as lithography, porous material synthesis and in drug delivery. Among various controlled radical polymerization (CRP) techniques, the combination of ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP) have received remarkable attention with regard to macroinitiator and block copolymer synthesis. Aliphatic polyesters such as poly (L-lactic acid) (PLLA) and poly(ε–caprolactone) (PCL) are interesting polymers for pharmacological, biomedical, environmental, and agricultural applications due to their good mechanical properties, high drug permeability, and biocompatibility. On the other hand, Polymethylmethacrylate (PMMA) is an acrylic hydrophobic biostable polymer that is widely used in the biomedical field as bone cement in orthopedics and traumatology and as implant carrier for sustained local delivery of anti-inflammatory or antibiotic drugs. PCL-PMMA block copolymer can improve the mechanical properties with reduced toxicity, and able to provide a partial biodegradable character to control the release of bioactive molecules. In this sense, PCL-b-PMMA block copolymer was synthesized, Cytotoxicity was determined against Artemia salina. It was found that the polymer was less toxic than the solvent (Ethyl acetate) was used to dissolve it. Antibacterial activity was tested against different bacteria and the polymer showed slide antibacterial activity by itself. Generally, drugs are poorly soluble in water. Furthermore, most bio-molecules have a very short half-life in vivo. Consequently, these compounds should be administered by immersing in a polymeric matrix. Therefore, in this study encapsulation of a drug (PTX) with this synthesized block copolymer was carried out by micellization method and release rate profile was also investigated against both a physiological pH (7.2) and a cell pH (5). Drug release rate was found to be more in cell pH than that of in physiological pH with controlled manner.
Key words: Bifunctional initiators; Macroinitiator; Block copolymer; Cytotoxicity; Antibacterial activity; Controlled release; pH responsive; Living radical polymerization.