title: Syntheses and characterization of amphiphilic quaternary ammonium chitosan derivatives.
abstract: Amphiphilic chitosan derivatives possess improved physico-chemical properties and could be used as carriers in drug delivery systems. The aim of this study was to investigate the behaviour of an amphiphilic system involving (5-pentyl) trimethylammonium and dodecyl aldehyde-modified chitosan. Amphiphilic chitosan derivatives were synthesized and characterized by (1)HNMR and ATR-FTIR spectroscopy. Self-assembled aggregates formed in aqueous solution have hydrophobic cores that were characterized by fluorescence spectroscopy using pyrene as probe and dynamic light scattering (DLS). The critical aggregation concentration of the aggregates in water varied from 0.004 to 0.037g/L and the average size distribution was in the 230-500nm range. The ζ-potential (+15.5 to +44.8mV) confirmed that the surfaces of the aggregates were positively charged and stable in physiological-like environments. TEM images suggest that the aggregates have a spherical shape, showing good agreement with DLS results. These results suggest that the synthesized copolymers have the capability of being used as carriers for hydrophobic drugs.
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, 13560-970 São Carlos, SP, Brazil. Electronic address: oliveira.ibilce@hotmail.com.
authors.forename: Rafael
authors.initials: R
authors.lastname: de Oliveira Pedro
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, 13560-970 São Carlos, SP, Brazil. Electronic address: carla@iqsc.usp.br.
authors.forename: Carla C
authors.initials: CC
authors.lastname: Schmitt
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, Caixa Postal 780, 13560-970 São Carlos, SP, Brazil. Electronic address: neumann@iqsc.usp.br.
authors.forename: Miguel G
authors.initials: MG
authors.lastname: Neumann
mesh_terms: D064751:Ammonium Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D048271:Chitosan / Q000138:chemical synthesis*; D004337:Drug Carriers / Q000138:chemical synthesis* / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry
chemical_list: D064751:Ammonium Compounds; D004337:Drug Carriers; D011108:Polymers; D048271:Chitosan
keywords: (5-Bromopentyl)trimethylammonium bromide (PubChem CID: 11098210); Amphiphilic derivatives; Chitosan; Chitosan (PubChem CID: 71853); Dodecyl aldehyde (PubChem CID: 8194); Fluorescence; Nanoaggregates; Pyrene (PubChem CID: 31423)