title: Encapsulation of diclofenac sodium within polymer beads by silica species via vapour-phase synthesis.
abstract: The present study concerns the preparation of ternary composites via the in situ encapsulation of solid dispersion of diclofenac sodium within the acrylic polymer beads. The encapsulating species were produced through the hydrolysis and condensation of the silica precursors (tetraethoxysilane or ethyltriethoxysilane) introduced into the solid dispersion. The transformation of precursors occurred in the vapor phase of ammonia. A great advantage of the presented vapor-phase method is preventing the desorption of the highly soluble drug during gelation of silica precursors, which stands in contrast to the conventional sol-gel processes occurring in the solution. The conducted studies, involving the low temperature N2 sorption together with spectroscopic techniques, provide insight into the structural differences of drug loaded particles. They reveal that the formation of silica gel accompanies the conversion of the drug into its amorphous form. Finally, the desorption profiles of diclofenac sodium demonstrate that the deposition of silica gel successfully diminishes the degree of the initial drug desorption while significantly modifying its release rate.
authors.affiliation: Maria Curie-Sklodowska University, Faculty of Chemistry, Department of Adsorption, 3M. Curie-Sklodowska Sq., Lublin 20-031, Poland. Electronic address: agnieszka.kierys@umcs.lublin.pl.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kierys
authors.affiliation: Medical University of Lublin, Faculty of Pharmacy, Department of Applied Pharmacy, 1 Chodzki Str, Lublin 20-093, Poland. Electronic address: reginakasperek@umlub.pl.
authors.forename: Regina
authors.initials: R
authors.lastname: Kasperek
authors.affiliation: Maria Curie-Sklodowska University, Faculty of Chemistry, Department of Adsorption, 3M. Curie-Sklodowska Sq., Lublin 20-031, Poland. Electronic address: patrycja.kosik@umcs.pl.
authors.forename: Patrycja
authors.initials: P
authors.lastname: Krasucka
authors.affiliation: Maria Curie-Sklodowska University, Faculty of Chemistry, Department of Adsorption, 3M. Curie-Sklodowska Sq., Lublin 20-031, Poland. Electronic address: jacek.goworek@umcs.lublin.pl.
authors.forename: Jacek
authors.initials: J
authors.lastname: Goworek
mesh_terms: D000641:Ammonia / Q000737:chemistry; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D003692:Delayed-Action Preparations; D004008:Diclofenac / Q000737:chemistry*; D004337:Drug Carriers; D004339:Drug Compounding / Q000379:methods*; D065546:Drug Liberation; D005782:Gels; D007700:Kinetics; D044367:Phase Transition; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D014835:Volatilization
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005782:Gels; D012821:Silanes; D004008:Diclofenac; C040733:tetraethoxysilane; D012822:Silicon Dioxide; D000641:Ammonia
keywords: Diclofenac sodium; Polymer-drug-silica composite; Porous polymers; Vapor-phase synthesis