title: Hydration induced material transfer in membranes of osmotic pump tablets measured by synchrotron radiation based FTIR.
abstract: Osmotic pump tablets are reliable oral controlled drug delivery systems based on their semipermeable membrane coating. This research used synchrotron radiation-based Fourier transform infrared (SR-FTIR) microspectroscopy and imaging to investigate the hydration induced material transfer in the membranes of osmotic pump tablets. SR-FTIR was applied to record and map the chemical information of a micro-region of the membranes, composed of cellulose acetate (CA, as the water insoluble matrix) and polyethylene glycol (PEG, as the soluble pore forming agent and plasticizing agent). The microstructure and chemical change of membranes hydrated for 0, 5, 10 and 30min were measured using SR-FTIR, combined with scanning electronic microscopy and atom force microscopy. The SR-FTIR microspectroscopy results indicated that there was a major change at the absorption range of 2700-3100cm(-1) in the membranes after different periods of hydration time. The absorption bands at 2870-2880cm(-1) and 2950-2960cm(-1) were assigned to represent CA and PEG, respectively. The chemical group signal distribution illustrated by the ratio of PEG to CA demonstrated that the trigger of drug release in the preliminary stage was due to the rapid transfer of PEG into liquid medium with a sharp decrease of PEG in the membranes. The SR-FTIR mapping results have demonstrated the hydration induced material transfer in the membranes of osmotic pump tablets and enabled reassessment of the drug release mechanism of membrane controlled osmotic pump systems.
authors.affiliation: School of Life Sciences, Jilin University, Changchun 130012, China; Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China.
authors.forename: Li
authors.initials: L
authors.lastname: Wu
authors.affiliation: Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China; Institute of Pharmaceutical Innovation, University of Bradford, Bradford, West Yorkshire BD7 1DP, United Kingdom.
authors.forename: Xianzhen
authors.initials: X
authors.lastname: Yin
authors.affiliation: Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China; Institute of Pharmaceutical Innovation, University of Bradford, Bradford, West Yorkshire BD7 1DP, United Kingdom.
authors.forename: Zhen
authors.initials: Z
authors.lastname: Guo
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
authors.forename: Yajun
authors.initials: Y
authors.lastname: Tong
authors.affiliation: Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Feng
authors.affiliation: Institute of Pharmaceutical Innovation, University of Bradford, Bradford, West Yorkshire BD7 1DP, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: York
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China.
authors.forename: Tiqiao
authors.initials: T
authors.lastname: Xiao
authors.affiliation: Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China. Electronic address: minchen@sinap.ac.cn.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.affiliation: School of Life Sciences, Jilin University, Changchun 130012, China. Electronic address: gujk@jlu.edu.cn.
authors.forename: Jingkai
authors.initials: J
authors.lastname: Gu
authors.affiliation: School of Life Sciences, Jilin University, Changchun 130012, China; Center for Drug Delivery Systems, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201210, China. Electronic address: jwzhang@simm.ac.cn.
authors.forename: Jiwen
authors.initials: J
authors.lastname: Zhang
mesh_terms: D002216:Captopril / Q000737:chemistry; D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000737:chemistry; D065546:Drug Liberation; D009995:Osmosis; D011092:Polyethylene Glycols / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared; D017356:Synchrotrons; D013607:Tablets / Q000737:chemistry*
chemical_list: D003692:Delayed-Action Preparations; D013607:Tablets; C005062:acetylcellulose; D011092:Polyethylene Glycols; D002482:Cellulose; D002216:Captopril
keywords: Cellulose acetate; Osmotic pump tablet; Polyethylene glycol; Semipermeable membrane; Synchrotron radiation based Fourier transform infrared spectroscopy