Bioevaluation of a novel [32P]‐CP‐PLLA microparticle for pancreatic cancer treatment

Abstract A novel [32P]‐CP‐PLLA ([32P]‐chromic phosphate‐poly‐L‐lactic acid) microparticle was designed and evaluated for the treatment of pancreatic carcinoma. The microparticle was prepared from [32P] chromic phosphate and poly‐L‐lactic acid. Bioelimination, biodistribution, SPECT image, and therapeutic effect were studied in mice bearing human pancreatic tumor xenografts. [32P]chromic phosphate ([32P]‐CP) colloid at the same radioactivity dose was compared as the control. High radioactivity (>95%ID) of [32P]‐CP‐PLLA was retained at the tumor, and almost no radioactivity excretion (<1%ID) was observed in urine and feces for 14 days, while radioactivity of [32P]‐CP colloid, was distributed to the liver, spleen, and lung (varied individual), and the excretion increased over 5%ID. Compared with controls, reduced tumor volumes were seen in the [32P]‐CP‐PLLA microparticle treatment group (P<0.01). Dose dependence was seen histologically. [32P]‐CP‐PLLA microparticle retained high activity and long‐term residence in tumor. With minimal distribution to normal organs [32P]‐CP‐PLLA microparticle is superior to [32P]‐CP colloid and is more suitable for brachytherapy in solid tumor. Drug Dev Res 71:364–370, 2010. © 2010 Wiley‐Liss, Inc.