Biodegradable Polymer Releasing Antibiotic Developed for Drainage Catheter of Cerebrospinal Fluid:In Vitro Results

The authors developed a biodegradable polymer that releases an antibiotic (nalidixic acid) slowly and continuously, for prevention of catheter-induced infection during drainage of cerebrospinal fluid. We investigated the in vitro antibiotic releasing characteristics and bacterial killing effects of the new polymer against E. coli. The novel fluoroquinolone polymer was prepared using diisopropylcarbodiimide, poly (e-capro-lactone) diol, and nalidixic acid. FT-IR, mass spectrometry, and elemental analysis proved that the novel antibacterial polymer was prepared successfully without any side products. Negative MS showed that the released drug has a similar molecular weight (M.W.=232, 350) to pure drug (M.W.=232). In high pressure liquid chromatography, the released drug and drug-oligomer showed similar retention times (about 4.5-5 min) in comparison to pure drug (4.5 min). The released nalidixic acid and nalidixic acid derivatives have antibacterial characteristics against E. Coli, Staphylococcus aureus, and Salmonella typhi, of more than 3 months duration. This study suggests the possibility of applying this new polymer to manufacture drainage catheters that resist catheter-induced infection, by delivering antibiotics for a longer period of more than 1 month.

Development of Biodegradable Polymer Releasing Anticancer Drug for Intratumoral Chemotherapy of Brain Tumor-in Vitro Results

OBJECTIVE: The authors present two polymers as carriers of anti-neoplastic agents for intratumoral chemotherapy. We investigated in vitro tumor cytotoxicity againt C6 glioma cells with 20ul cis-platinum (CDDP)-polymer. METHODS: We firstly developed new two thermosensitive sol-gel reVersible polymer (poly-2 and poly-6) by random copolyerization from ethylene glycol and caprolactone polymer that is sol state over 50degrees C but changed gradually to gel less than 50degrees C We evaluated the time-related release profiles of 10mg cisplatin from CDDP-Poly 2 and CDDP-Poly 6 in 25ml of pH 7.4 phosphate buffer saline using UV spectrophotometer during 31days. We cultured C6 glioma cell line in 10cm round plates for 2 days and added 20microliter of CDDP-polymer containing 30uM of CDDP into the center of each plate. We counted C6 cell number every 12 hours for 72 hours at same 3 sites of each 6 well plates. RESULTS: UV spevtrophotometry showed total 12.6% of CDDP released from CDDP-poly 2 and total 56.9% of CDDP from CDDP-poly 6 on 31 days. Both carrier polymer showed total released amount of CDDP directly correlated with time without initial dumping effect. The CDDP released from 20microliter of CDDP-poly 2 and CDDP-poly 6 in 48 hours showed cytotoxicity to C6 glioma cells more than 50% in vitro cell culture system. CONCLUSION: This results suggest that less than 20microliter CDDP-polymer could be applied in vivo brain tumor model to show significant cytotoxicity.