title: Analysis of the microcrystalline inclusion compounds of triclosan with β-cyclodextrin and its tris-O-methylated derivative.
abstract: Solid 1:1 inclusion compounds of triclosan with native and permethylated β-cyclodextrin (β-CD and TRIMEB) were prepared by co-crystallisation and co-evaporation, respectively, and studied by FT-IR and (13)C{(1)H} CP/MAS NMR spectroscopies, thermogravimetric analysis, X-ray diffraction and theoretical calculations. Results showed that triclosan inclusion into TRIMEB afforded an amorphous solid, whilst β-CD·triclosan is composed of microcrystals belonging to two different phases. In the phase featuring larger crystals, X-ray diffraction was carried out and the β-CD host units, packing head-to-head in infinite channels, were refined; the geometry for the included but highly disordered triclosan molecules was assessed by theoretical calculations. The bacterial growth inhibitory action of the inclusion compounds was studied in comparison to that of pure triclosan on Gram-negative (Salmonella, Escherichia) and Gram-positive strains (Bacillus, Listeria, Enterococcus and Staphylococcus) typically associated with human pathologies, and also on environmental bacteria isolated from different soil and water sources. The antimicrobial activities obtained in the present work showed that, of the two CD hosts, TRIMEB brings the most favourable carrier effect: it reduced the toxicity of triclosan against some of the environmental strains and afforded slightly higher action against virulent strains.
authors.affiliation: Department of Chemistry, CICECO, University of Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Ana I
authors.initials: AI
authors.lastname: Ramos
authors.forename: Teresa M
authors.initials: TM
authors.lastname: Braga
authors.forename: José A
authors.initials: JA
authors.lastname: Fernandes
authors.forename: Patrícia
authors.initials: P
authors.lastname: Silva
authors.forename: Paulo J
authors.initials: PJ
authors.lastname: Ribeiro-Claro
authors.forename: Filipe A
authors.initials: FA
authors.lastname: Almeida Paz
authors.forename: Maria
authors.initials: M
authors.lastname: de Fátima Silva Lopes
authors.forename: Susana S
authors.initials: SS
authors.lastname: Braga
mesh_terms: D000891:Anti-Infective Agents, Local / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D003460:Crystallization; D003505:Cyclodextrins / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D004783:Environmental Microbiology; D006090:Gram-Negative Bacteria / Q000187:drug effects / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000187:drug effects / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy; D010316:Particle Size; D017550:Spectroscopy, Fourier Transform Infrared; D013818:Thermogravimetry; D014260:Triclosan / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D014961:X-Ray Diffraction; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D000891:Anti-Infective Agents, Local; D003505:Cyclodextrins; D004337:Drug Carriers; D047392:beta-Cyclodextrins; C487420:heptakis(2,3,6-tri-O-methyl)cyclomaltoheptaose; D014260:Triclosan; C031215:betadex