title: Preclinical antitumor activity of a nanoparticulate SN38.
abstract: The present studies were carried out to examine the efficacy of a nanoparticulate formulation of SN38, the potent topoisomerase I inhibitor and active metabolite of irinotecan. Metabolism of irinotecan to SN38 is inefficient and subject to considerable patient-to-patient variability. One approach to more controlled administration of the anticancer agent is direct administration of the active SN38. A nanoparticulate formulation of SN38 was prepared by a method of precipitation with compressed antisolvent. Nanoparticulate SN38 efficiently inhibited the proliferation of colorectal, ovarian, and mesothelial cancer cell lines in vitro. Concentrations resulting in 50 % inhibition of proliferation were approximately 1000 fold lower for nanoparticulate SN38 compared to irinotecan. In vivo effects were examined using colorectal and ovarian mouse model systems. In a mouse model of peritoneally disseminated ovarian cancer intraperitoneal administration of irinotecan was favorable to intravenous delivery however intraperitoneal delivery of nanoparticulate SN38 was significantly more effective than intraperitoneal irinotecan. In addition, in a mouse colorectal cancer model administration of nanoparticulate SN38 once weekly exhibited greater activity compared to daily or weekly administration of irinotecan. Additional studies demonstrated nanoparticulate SN38 administered as a combination therapy with mitomycin C was more effective than the combination of irinotecan and mitomycin C. Results from the present studies using preclinical colorectal and ovarian cancer model systems demonstrate the efficacy of nanoparticulate SN38 and substantiate continued development.
authors.affiliation: Department of Surgery, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Mazin F
authors.initials: MF
authors.lastname: Al-Kasspooles
authors.forename: Stephen K
authors.initials: SK
authors.lastname: Williamson
authors.forename: David
authors.initials: D
authors.lastname: Henry
authors.forename: Jahna
authors.initials: J
authors.lastname: Howell
authors.forename: Fengui
authors.initials: F
authors.lastname: Niu
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Decedue
authors.forename: Katherine F
authors.initials: KF
authors.lastname: Roby
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D049109:Cell Proliferation / Q000187:drug effects; D005260:Female; D045325:HCT116 Cells; D006801:Humans; D000077146:Irinotecan; D051379:Mice; D016685:Mitomycin / Q000494:pharmacology / Q000627:therapeutic use; D053758:Nanoparticles / Q000737:chemistry / Q000627:therapeutic use*; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology; D016019:Survival Analysis; D023041:Xenograft Model Antitumor Assays
chemical_list: D016685:Mitomycin; D000077146:Irinotecan; D002166:Camptothecin