title: Quantitative acid hydrolysis of DE-310, a macromolecular carrier system for the camptothecin analog DX-8951f.
abstract: DE-310 is a novel macromolecular prodrug of the topoisomerase-I inhibitor DX-8951. DX-8951 is covalently linked to carboxymethyl dextran polyalcohol (CM-Dex-PA) via a Gly-Gly-Phe-Gly (GGFG) tetrapeptide spacer. The present study was conducted to identify the portions of DX-8951 linked to DE-310, as well as to quantify the number of DX-8951 molecules associated with DE-310. Two different structures terminated with either glycolaldehyde (CM-GA-GGFG-DX-8951) or glycerol (CM-Glr-GGFG-DX-8951) are obtained when the polymer backbone is fragmented with 1 M HCl. The two products, i.e., CM-GA-GGFG-DX-8951 and CM-Glr-GGFG-DX-8951, indicate linkage of GGFG-DX-8951 with carboxymethyl (CM) group at C-2 and C-4 position of the glucose units, respectively. In the present study, CM-GA-GGFG-DX-8951 was reduced to CM-ethyleneglycol (EG)-GGFG-DX-8951 in order to improve stability prior to HPLC analysis. Hydrolysis results revealed that the amount of CM-GA-GGFG-DX-8951 liberated was 84.7 nmol/mg DE-310 and the amount of CM-Glr-GGFG-DX-8951 was 71.8 nmol/mg DE-310. Considering the ratio of generation between CM-GA-GGFG-DX8951 and CM-Glr-GGFG-DX8951, it suggested that slightly larger amount of GGFG-DX-8951 was linked to carboxymethyl groups at the C-2 position of glucose units in DE-310. The sum of the amounts of CM-GA-GGFG-DX-8951 and CM-Glr-GGFG-DX-8951 agrees well with the amount of G-DX-8951 produced from DE-310 by alpha-chymotrypsin treatment (157.5 nmol/mg DE-310). The data indicate that the established hydrolysis give a quantitative evaluation of the DX-8951 linked to DE-310.
authors.affiliation: New Product Research Laboratories III, Daiichi Pharmaceutical Co. Ltd., Tokyo R&D Center, Kita-Kasai 1-16-13, Edogawa-Ku, Tokyo 134-8630, Japan. shiosf62@daiichipharm.co.jp
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Shiose
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kuga
authors.forename: Fumiyoshi
authors.initials: F
authors.lastname: Yamashita
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Hashida
mesh_terms: D000143:Acids / Q000737:chemistry*; D002166:Camptothecin / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004337:Drug Carriers / Q000737:chemistry*; D004355:Drug Stability; D004791:Enzyme Inhibitors / Q000032:analysis* / Q000737:chemistry; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D011355:Prodrugs / Q000737:chemistry; D015203:Reproducibility of Results
chemical_list: D000143:Acids; D004337:Drug Carriers; D004791:Enzyme Inhibitors; D011355:Prodrugs; C095887:exatecan; D002166:Camptothecin