The authors have been devising novel dosage forms with a sustained release of aqueous cis-platinum (CDDP), following the concept of a drug delivery system. First, we prepared biodegradable vehicles with clinically available fibrin and gelatin materials that were used with the ultraviolet (UV)-cross linking technique. Then, each carrier was loaded with CDDP to form new drugs. We basically studied degradability of the carrier, a release profile of the CDDP, and antineoplastic activities with the system. The new drugs gradually disintegrated to dissolve completely within 10-15 days, and 80-90% of the loaded CDDP was delivered in the same period. The released CDDP showed antineoplastic activities, both in vitro and in vivo, while the CDDP directly reacted with human plasma revealed little evidence of anticancer function. The scanning electron microscopic studies suggested that the release profile of the CDDP was closely related with the degradability of the carrier. We presume that UV-modification techniques play important roles in preparation of the new drug carriers. Our newly devised CDDP releasing system is promising as novel cancer chemotherapy.