title: Novel aqueous chitosan-based dispersions as efficient drug delivery systems for topical use. Rheological, textural and release studies.
abstract: The use of a novel cross-linked thiolated chitosan (CTS) was investigated as the main component of aqueous dispersions (at 1% and 3% w/v) for topical drug delivery systems. The nonionic theophiline (Th) and the cationic diltiazem(.)HCl (Dt) (at 0.5% w/v concentration) were used as model drugs. All aqueous dispersions behaved as viscoelastic fluids. The CTS 1% dispersions showed predominance of viscous component and low viscosity. However, in the CTS 3% dispersions, both the elastic component and high viscosities prevailed. So, texture parameters improved from CTS 1% to 3% dispersions and CTS 3%-Dt showed greater cohesion and adhesion than CTS 3%-Th, but always below CTS alone. All dispersions showed a Fickian diffusion mechanism. Despite release profiles of both drugs almost fully overlapped at 1% CTS, diffusion coefficients confirmed Dt released faster than Th at 3% CTS. The rheological behavior and the chemical nature of the drugs explained these results.
authors.affiliation: Dpto. de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García González no. 2, 41012 Sevilla, Spain. Electronic address: mjlucero@us.es.
authors.forename: M J
authors.initials: MJ
authors.lastname: Lucero
authors.affiliation: Dpto. Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García González no. 2, 41012 Sevilla, Spain. Electronic address: cferris@us.es.
authors.forename: C
authors.initials: C
authors.lastname: Ferris
authors.affiliation: Dpto. de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García González no. 2, 41012 Sevilla, Spain. Electronic address: csanchez17@us.es.
authors.forename: C A
authors.initials: CA
authors.lastname: Sánchez-Gutiérrez
authors.affiliation: Dpto. de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García González no. 2, 41012 Sevilla, Spain. Electronic address: mrosa@us.es.
authors.forename: M R
authors.initials: MR
authors.lastname: Jiménez-Castellanos
authors.affiliation: Dpto. Química Orgánica y Farmacéutica, Facultad de Farmacia, Universidad de Sevilla, Prof. García González no. 2, 41012 Sevilla, Spain. Electronic address: vdepaz@us.es.
authors.forename: M-V
authors.initials: MV
authors.lastname: de-Paz
mesh_terms: D000287:Administration, Topical; D048271:Chitosan / Q000737:chemistry*; D004110:Diltiazem / Q000008:administration & dosage / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D065546:Drug Liberation; D007700:Kinetics; D012212:Rheology; D014783:Viscosity; D014867:Water / Q000737:chemistry*
chemical_list: D004337:Drug Carriers; D014867:Water; D048271:Chitosan; D004110:Diltiazem
keywords: Anhydrous theophylline; Diltiazem hydrochloride; Drug release; Hydrogels; Rheological characterization; Thiolated-chitosan