External control of drug release. IV. Controlled release of 5-fluorouracil from a hydrophilic polymer matrix by microwave irradiation.

A polymeric system capable of delivering 5-fluorouracil (5-FU) at increased rates on demand by external microwave irradiation was developed. Sustained-release systems were made by incorporating 5-FU into an ethylene-vinyl alcohol copolymer. When exposed to release medium, the delivery systems released the drug slowly and continuously. Upon exposure to microwave irradiation, the drug was released at a much higher rate. Release rates returned to base line levels when the microwave irradiation was discontinued. This study demonstrated that release rates of 5-FU from a polymer matrix can be increased at desired times by external microwave irradiation.