188Re-SOCTA-Chitosan and hepatoma animal model study

Objectives The study is to evaluate the labeling of chitosan with 188Re through a new bifunctional N2S2 ligand SOCTA. Chitosan, a kind of biodegradable biopolymer and aggregated in an alkaline environment,when it was labeled by radioisotopes and injected around tumor cells so that aggregated on the tumor,close-up of energy released to kill cancer cells. It can biodegradable over time, and reduce the harm of body.

Methods 188Re is an attractive radioisotope emitting 2.12 MeV β particles to result in the damage of cancer cell. SOCTA,(succinimidy-3,6-diaza-5-oxo-3-[2- ((tri-phenylmethyl)thio)ethyl]-8-[(triphenylmethyl)thio]octanoate),was used to as a bifunctional chelating agent to conjugate with Chitosan and 188Re.

Results The radiochemical purity of 188Re-SOCTA-Chitosan, checked by TLC, was more than 95%. Each SD rat was injected with 0.2~0.3mCi/0.1ml (n=25) of 188Re-SOCTA-Chitosan through intra tumor injection. 25 SD rat were equally separated into 5 groups and sacrificed at 1, 3, 6, 24 and 48 hours post-injection. Two rat were left to take the distribution image using micoSPECT/CT. The biodistribution data showed that 188Re-SOCTA-Chitosan has the tendency to accumulate at the tumor site. It was 12.46±3.68%, 9.74±4.40%, 3.87±3.29%, 4.15±1.52%, 5.30±1.65%(expressed as %ID/g) respectively in 1, 3, 6, 24 and 48 hours. From microSPECT/CT images, 188Re-SOCTA-Chitosan is stable distributed at tumor in 1~48 hours.

Conclusions The data showed that 188Re-SOCTA-Chitosan has the potential to be a therapeutic radiopharmaceutical for cancer treatment. We need long-term follow-up efficacy assessment of the future potential of drugs. Chitosan receive much attention in recent years, a natural polymer, in addition to as a health food products, food processing, environmental engineering, biochemical separation, biomedical materials, as well as the areas of drug release may have their applications, and future opportunities for unlimited if we can be in-depth study will be able to biotech industry in Taiwan has played a decisive role