[Novel pharmaceutical and biomedical applications of plasma techniques].

The plasma-induced surface radicals formed on a variety of organic polymers have been studied in detail using electron-spin resonance (ESR) coupled with systematic computer simulations. On the basis of the findings from such studies on the nature of radical formation and radical reactivity, we were able to open up several novel pharmaceutical and biomedical applications in plasma treatment. In this review, applications using plasma-irradiated organic polymers are described, which include: 1) preparation of double-compressed tablets applicable for reservoir-type drug-delivery systems (DDS) for sustained and delayed release, intragastric floating DDS (FDDS) for oral controlled-release dosage forms with gastric retention capabilities, and fabrication of functionalized composite powders applicable for controlled drug release with the mechanical application of plasma-irradiated polymer powder; 2) an approach to "patient-tailored DDS," administered by taking into account that the environment (pH, transit time, etc.) in the gastrointestinal tract varies with each patient, based on the combination of the above-mentioned DDS devices; 3) plasma-assisted promotion of seed germination of herbal medicines with hard coats; and 4) fabrication of polymer surfaces with durable hydrophilicity and lubricity using plasma techniques and the immobilization of oligo-nucleotides on hydrophilic polymer surfaces thus prepared applicable to constructing DNA diagnosis systems.