title: Lysozyme-magnesium aluminum silicate microparticles: Molecular interaction, bioactivity and release studies.
abstract: The objectives of this study were to investigate the adsorption behavior of lysozyme (LSZ) onto magnesium aluminum silicate (MAS) at various pHs and to characterize the LSZ-MAS microparticles obtained from the molecular interaction between LSZ and MAS. The results showed that LSZ could be bound onto the MAS layers at different pHs, leading to the formation of LSZ-MAS microparticles. The higher preparation pH permitted greater adsorption affinity but a lower adsorption capacity of LSZ onto MAS. LSZ could interact with MAS via hydrogen bonds and electrostatic forces, resulting in the formation of intercalated nanocomposites. The particle size, %LSZ adsorbed, and LSZ release rate of LSZ-MAS microparticles increased when the LSZ-MAS ratio was increased. The secondary structure of LSZ bound onto the MAS layers in microparticles prepared at various pHs was altered compared with that of native LSZ. Moreover, the LSZ extracted from microparticles prepared at pH 4 showed an obvious change in the tertiary structure, leading to a decrease in the biological activity of the LSZ released. These findings suggested that LSZ can strongly interact with MAS to form microparticles that may potentially be used as delivery systems for sustained protein release.
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
authors.forename: Watchara
authors.initials: W
authors.lastname: Kanjanakawinkul
authors.affiliation: School of Pharmacy, University of Otago, Dunedin 9054, New Zealand.
authors.forename: Natalie J
authors.initials: NJ
authors.lastname: Medlicott
authors.affiliation: School of Pharmacy, University of Otago, Dunedin 9054, New Zealand; Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100 Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rades
authors.affiliation: Department of Manufacturing Pharmacy, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand.
authors.forename: Satit
authors.initials: S
authors.lastname: Puttipipatkhachorn
authors.affiliation: Faculty of Pharmaceutical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand. Electronic address: thaned@kku.ac.th.
authors.forename: Thaned
authors.initials: T
authors.lastname: Pongjanyakul
mesh_terms: D000327:Adsorption; D017607:Aluminum Compounds / Q000737:chemistry*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D017616:Magnesium Compounds / Q000737:chemistry*; D008958:Models, Molecular; D009113:Muramidase / Q000737:chemistry*; D053761:Nanocomposites / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D011487:Protein Conformation; D017640:Silicates / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D055672:Static Electricity
chemical_list: D017607:Aluminum Compounds; D017616:Magnesium Compounds; D017640:Silicates; C033065:aluminum magnesium silicate; D009113:Muramidase
keywords: Bioactivity; Lysozyme; Magnesium aluminum silicate; Microparticles; Protein conformation; Protein release