title: Preparation and characterisation of alendronate-loaded chitosan microparticles obtained through the spray drying technique.
abstract: Microparticles of chitosan (CHT) containing alendronate sodium (AL) were prepared in four drug:polymer ratios (1:1, 1:2, 1:4, 1:6) using the spray drying technique. The efficiency of the method was evaluated by determining production yield (about 70 %) and microencapsulation efficiency, which was almost 100 % in the case of all four of the formulations studied. Particles had a mean size of between 3.6 and 4.6 microm, and a near-spherical shape. The formulations with the highest content of AL (drug:polymer ratio 1:1 and 1:2) showed an asymmetrical distribution of particles, which were larger in size, and had a higher proportion of irregular particles than the other formulations. FT-IR analysis revealed an ionic interaction between AL and CHT. Differential scanning calorimetry and thermogravimetric analysis confirmed the microencapsulation of AL and the increased thermal stability of encapsulated AL. The dissolution profiles of AL from CHT microspheres, at pH values of 1.2 and 6.8, showed a delayed release of AL from microspheres, and the dissolution rate was dependent on the pH and the drug:polymer ratio. It can be concluded that spray drying is a suitable technique for preparing AL-loaded CHT microspheres, and that the drug:polymer ratio can be used to control the rate of AL release from microspheres.
authors.affiliation: Department of Pharmacy and Pharmaceutical Technology. Faculty of Pharmacy. University of Valencia. Avda. V. Andres Estellés s/n. 46100-Burjassot, Valencia, Spain.
authors.forename: Lacramioara
authors.initials: L
authors.lastname: Ochiuz
authors.forename: José-Esteban
authors.initials: JE
authors.lastname: Peris
mesh_terms: D019386:Alendronate / Q000008:administration & dosage* / Q000737:chemistry / Q000493:pharmacokinetics; D001682:Biological Availability; D002152:Calorimetry, Differential Scanning; D048271:Chitosan / Q000737:chemistry*; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D010316:Particle Size; D013055:Spectrophotometry, Infrared; D013499:Surface Properties; D013818:Thermogravimetry
chemical_list: D004337:Drug Carriers; D048271:Chitosan; D019386:Alendronate