title: Microencapsulation by spray coagulation of diltiazem HCl in calcium alginate-coated chitosan.
abstract: The aim of this work was to develop a procedure for encapsulation of diltiazem HCl by spray coagulation. Factors affecting the formulations such as the effect of NaCl on the solubility of diltiazem in alginate solution, surface tension, pH, viscosity of the coagulation medium, and the effect of drug load on drug release were studied. The drug load was increased substantially from 10 up to 320 mg/mL by adding 1.2% w/v NaCl in 1% w/v alginate solution. More stable microcapsules were obtained at pH 4.6 (acetate buffer) than at a pH 2.8 (lactic acid), and the microencapsulation process was favored by the type of chitosan that produced low turbidity and viscosity in the coagulation medium. A dose of 50 mg/mL of diltiazem HCl, 1.2% w/v NaCl, and chitosan CS allowed higher amount of drug to be encapsulated. The high water solubility of diltiazem HCl leads to fast release from the microcapsules.
authors.affiliation: Laboratorio de Operaciones Unitarias, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Casilla 233, Santiago 1, Chile. ctapia@uchile.cl
authors.forename: Cristián
authors.initials: C
authors.lastname: Tapia
authors.forename: Víctor
authors.initials: V
authors.lastname: Montezuma
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Yazdani-Pedram
mesh_terms: D000464:Alginates / Q000737:chemistry*; D048271:Chitosan / Q000737:chemistry*; D004110:Diltiazem / Q000737:chemistry*; D004339:Drug Compounding; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D012995:Solubility; D017550:Spectroscopy, Fourier Transform Infrared; D013500:Surface Tension; D014783:Viscosity
chemical_list: D000464:Alginates; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D048271:Chitosan; D004110:Diltiazem