title: Imaging of drug loading distributions in individual microspheres of calcium silicate hydrate--an X-ray spectromicroscopy study.
abstract: Imaging is one of the most direct and ideal ways to track drug loading distributions in drug carriers on the molecular level, which will facilitate the optimization of drug carriers and drug loading capacities. Herein, we report the mapping of an individual mesoporous calcium silicate hydrate (CSH) microsphere before and after the loading of ibuprofen (IBU) and the interactions between drug carriers and drug molecules simultaneously by scanning transmission X-ray microscopy (STXM). Nanoscaled X-ray absorption near edge structure (XANES) spectroscopy clearly indicates that IBU is bonded to calcium and silicate sites via carboxylic acid groups. More importantly, STXM has been successfully used to determine the absolute thickness of IBU, revealing its distribution in the CSH microsphere.
authors: Department of Chemistry, University of Western Ontario, London, Ontario N6A 5B7, Canada. tsham@uwo.ca.
authors: Xiaoxuan
authors: X
authors: Guo
authors: Zhiqiang
authors: Z
authors: Wang
authors: Jin
authors: J
authors: Wu
authors: Jian
authors: J
authors: Wang
authors: Ying-Jie
authors: YJ
authors: Zhu
authors: Tsun-Kong
authors: TK
authors: Sham
mesh_terms: D017610:Calcium Compounds / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry; D004337:Drug Carriers; D016503:Drug Delivery Systems; D004577:Electron Probe Microanalysis; D006801:Humans; D007052:Ibuprofen / Q000008:administration & dosage; D046529:Microscopy, Electron, Transmission; D008863:Microspheres; D049329:Nanostructures / Q000737:chemistry; D011208:Powders; D017640:Silicates / Q000737:chemistry*; D014466:Ultraviolet Rays
chemical_list: D017610:Calcium Compounds; D002264:Carboxylic Acids; D004337:Drug Carriers; D011208:Powders; D017640:Silicates; C031293:calcium silicate; D007052:Ibuprofen