title: Comparing techniques for drug loading of shape-memory polymer networks--effect on their functionalities.
abstract: A family of oligo[(epsilon-caprolactone)-co-glycolide]dimethacrylate (oCG-DMA) derived networks of different glycolide contents as well as precursor molecular weights has been synthesized by crosslinking oCG-DMA, providing matrices of different hydrophilicity, network density, and morphology at body temperature. Such networks were loaded with a hydrophilic model drug, ethacridine lactate, either before crosslinking or afterwards by swelling in drug solution. Disadvantageous alterations of the shape-memory functionality and degradation characteristics were observed only in few loaded materials. Loading by swelling generally resulted in low payloads, which slightly increased for more hydrophilic polymer networks, and a substantial burst and fast subsequent release for all investigated materials. Loading before crosslinking gave almost no burst and higher subsequent release rates over longer periods of time. Overall, depending on the needs of a specific application, a material from this polymer family with the desired mechanical properties, shape-memory functionality, and degradation pattern can be selected and combined with drugs when considering that (i) loading by swelling is best suited for applications that require high initial doses and (ii) loading before crosslinking allows easy variation of payloads and low burst release for therapeutics that are non-sensitive to chemical alterations during crosslinking.
authors.affiliation: Center for Biomaterial Development, Institute of Polymer Research, GKSS Research Center Geesthacht GmbH, Kantstrasse 55, 14513 Teltow, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Wischke
authors.forename: Axel T
authors.initials: AT
authors.lastname: Neffe
authors.forename: Susi
authors.initials: S
authors.lastname: Steuer
authors.forename: Andreas
authors.initials: A
authors.lastname: Lendlein
mesh_terms: D011108:Polymers / Q000737:chemistry*; D012996:Solutions
chemical_list: D011108:Polymers; D012996:Solutions