Abstract
Shirasu porous glass particles (SPG) having a lot of pores of 500Å in diameter were prepared as a new drug carrier for cancer chemotherapy, and their chemical and biological features were studied. The particles are composed of SiO2, Al2O3 and Bl2O3, and their mean diameter is 10μm. Bleomycin(BLM) was used as an anti-cancer agent. SPG and BLM were shaken in saline of thermoincubator for 1 hour so that SPG could effectively adsorb BLM (SPG-BLM). About 40% of BLM was adsorbed to SPG at 37°C. On the other hand, the desorption of BLM from SPG-BLM was occurred in keeping the sigmoid relationship with the degree of dilution. The desorption rate was 82%, when SPG-BLM was diluted 8 times in saline. While ELM was immediately solved in saline, only about 30% of BLM was released into saline from SPG-BLM through the dialytic membrane at room temperature during 14 days. The biological activity of BLM was measured by thin agar plate bioassay using Bacillus subtilis PCL-219. The higher the concentration of SPG-BLM, the more significant the activity of BLM. And the activity became marked with the passage of time. In an acute toxicity experiment, no remarkable side-effects were observed both pharmacologically and histopathologically. Consequently, it was suggested that SPG are useful as a drug carrier and that administration of SPG-BLM is an effective anti-cancer modality especially in local chemotherapy.
