Tailoring of Drug Release Kinetics by Partition Effect via Drug Immobilization

Drug laden films have been widely used in biomedical applications for therapy purposes. One of the key challenges is to realize zero-order sustained release profile for prolonged therapeutic effect. One of the approaches is to load the drug into microspheres and then embed drug laden microspheres into the film so that the drug has to partition into the film before it can be released. A partition control scheme is recently reported, which reduces drug partition coefficient and leaves drug diffusivity intact by drug immobilization. Therefore it is hypothesized that the drug release duration and order of the release profile of polymeric film embedded with drug laden microspheres could be tailored by immobilizing certain amount of drug inside the film. This paper realizes the near zero-order release profile with suitable amount of immobilization; moreover the total duration of the drug release can be extended from a few hours to more than half a month after applying the partition control scheme.