Polymers in drug delivery

Polymeric systems have wide applications in drug delivery, both as soluble and as particulate systems. Polymers can also be used as coating agents to protect or deliver drugs to specific sites in the body. Particulate systems based on biodegradable polymers have recently become of special interest. Many of these systems are based on microparticles made from polylactide or polylactide-co-glycolide copolymers, although some new materials such as poly(organo) phosphazenes have been introduced. Recent research on the use of microparticles for drug targeting has seen the introduction of new poly(ethylene oxide) copolymers, such as polylactide—poly(ethylene oxide). In aqueous media these materials spontaneously form micelle-like particles where the core, made from the hydrophobic moiety of the copolymer, may encapsulate a drug.