Abstract
As part of our continuing work on plasma chemistry and its application for the preparation of new pharmaceutically useful materials, we have examined preparations of multilayered particles applicable for DDS by use of plasma processing, and found that controlled-release tablet can be obtained by oxygen plasma irradiation (radio-frequency discharges operating at 13.56 MHz) on the outermost layer of the double-compressed tablet which were fabricated from theophylline tablet as a core material and a mixture of plasma-degradable polyoxymethylene (POM) and plasma-crosslinkable-polystyrene (PST) as a wall material. Dissolution test clearly indicated that the theophylline has been released from the tablet through the resulting micropore, whilst the release from untreated tablets was negligible. It was also found that dissolution profiles of theophylline can readily be controlled by the selection of a variety of factors for tablet fabrications as well as plasma operational conditions. One of the advantages of the present method over other methods is the avoidance of direct plasmaexposure to the drug.
