[Injectable drug carriers with sustained release of cis-platinum]

The authors devised injectable drug carriers with sustained release of cis-platinum (CDDP). We formed the carriers using biodegradable medical materials applied clinically: namely, fibrin hydrogel clot (FC) made from tissue adhesive, and gelatin powder (Gp) for hemostasis. Two different types of carriers were prepared: plain fibrin hydrogel clots (FCs) and Gp-containing FCs. Each carrier was dehydrated and crushed into granules, then irradiated with ultraviolet (UV) rays. These modified materials were saturated with a CDDP solution to prepare CDDP-loaded injectable sol, which were incubated at 37 degrees C in our experimental fibrinolytic systems. We examined the in vitro release profile of the CDDP and antineoplastic activities with the drug delivered from the sol. The UV-treated materials gradually released the CDDP over more than 20-30 days. Non-UV-treated carriers released the drug within 3-5 days. More than 90% of the released CDDP was revealed to be a protein-binding type, which favorably inhibited the growth of cultured cancer cells. Conversely, the CDDP incubated with human plasma showed no inhibiting functions against the growth of cancer cells. Our newly devised material appears to have great potential for loco-regional cancer chemotherapy based on the principle of local drug delivery.