Use of palladacycle complexes anchored on chitosan as oral antineoplasic drugs with colon-specific carriers

• Grant number: 09/13256-8
• Support Opportunities: Scholarships in Brazil - Master
• Start date: August 01, 2010
• End date: February 29, 2012
• Field of knowledge: Biological Sciences - Pharmacology - Biochemical and Molecular Pharmacology
• Principal Investigator: Elaine Guadelupe Rodrigues
• Grantee: Daniel Moreno Garcia
• Host Institution: Pró-Reitoria de Pesquisa, Pós-Graduação e Extensão e Assuntos Comunitários. Universidade de Mogi das Cruzes (UMC). Mogi das Cruzes , SP, Brazil

Abstract

The use of natural polysaccharides such as chitosan has recently been widely used as systems for specific colon drug delivery. This is due among other things, the presence in the colon of a specific microflora which consists of a large number and variety of bacteria capable of secreting a wide range of different enzymes, for example, ²-glucuronidase, ²-xylosidase, ±-arabinosidase, among others, are able to degrade chitosan thus causing a reduction of its molecular weight, a loss of mechanical strength and is therefore unable to maintain its structure in any anchored drug. Chitosan is a non-toxic polymer, biodegradable, obtained by deacetylation of chitin, a natural biopolymer derived mainly from the exoskeleton of crustaceans and cell walls of fungi and insects. Thus, we intend with development of this project, synthesizing new antitumour cyclopalladated compounds derived from the cyclometallation agent N, N-diethyl-phenylamide, anchored on chitosan. This palladacycle has a pro-chiral center, containing a carbonyl group and a similar structure to active compounds that we have synthesized involving N, N-dimethyl-1-phenethylamine. Due the presence of carbonyl group in the molecule of this organometallic complex, it may be anchored on the surface of chitosan, using ATPES (3-aminopropyl triethoxy silane) as anchoring agent. Once obtained the anchored cyclopalladated complex, biphosphine derivatives will be synthezised by use of the ligands DPPE (1,2-diphenylphosphino-ethane) and DPPF (1,1 '-bis-diphenylphosphino) ferrocene. The biphosphine complexes will be assayed in-vitro and in-vivo as potential anticancer agents, specially the colon neoplasy. Our Research Group on Organometallic Compounds (CIIB/ Universidade de Mogi das Cruzes) has achieved many advances in mechanistic elucidating and "design" of new organometallic drugs involving palladacycle compounds. The success of the projects in this area has resulted in an international patent on behalf of FAPESP. Currently, we have joint projects involving UMC, INCA, and FIOCRUZ in Rio de Janeiro besides being inserted in the INCT for Cancer Control. Phase-I clinical trials of our main complexes are being begun. In this stage of development, find the way of administration and appropriate biological vehicles of the drugs constitute important technological difficulties as well as in the so-called "State of the Art" of this project. (AU)