title: A solid-state NMR method to determine domain sizes in multi-component polymer formulations.
abstract: Polymer domain sizes are related to many of the physical properties of polymers. Here we present a solid-state NMR experiment that is capable of measuring domain sizes in multi-component mixtures. The method combines selective excitation of carbon magnetization to isolate a specific component with proton spin diffusion to report on domain size. We demonstrate the method in the context of controlled release formulations, which represents one of today's challenges in pharmaceutical science. We show that we can measure domain sizes of interest in the different components of industrial pharmaceutical formulations at natural isotopic abundance containing various (modified) cellulose derivatives, such as microcrystalline cellulose matrixes that are film-coated with a mixture of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC).
authors.affiliation: Université de Lyon, Institut de Science Analytiques, Centre de RMN à très hauts champs (CNRS/ENS Lyon/UCB Lyon1), Villeurbanne, France.
authors.forename: Judith
authors.initials: J
authors.lastname: Schlagnitweit
authors.affiliation: Université de Lyon, Institut de Science Analytiques, Centre de RMN à très hauts champs (CNRS/ENS Lyon/UCB Lyon1), Villeurbanne, France.
authors.forename: Mingxue
authors.initials: M
authors.lastname: Tang
authors.affiliation: Université de Lyon, Institut de Science Analytiques, Centre de RMN à très hauts champs (CNRS/ENS Lyon/UCB Lyon1), Villeurbanne, France.
authors.forename: Maria
authors.initials: M
authors.lastname: Baias
authors.affiliation: AstraZeneca R&D Pharmaceutical Development, Mölndal, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Richardson
authors.affiliation: AstraZeneca R&D Pharmaceutical Development, Mölndal, Sweden.
authors.forename: Staffan
authors.initials: S
authors.lastname: Schantz
authors.affiliation: Université de Lyon, Institut de Science Analytiques, Centre de RMN à très hauts champs (CNRS/ENS Lyon/UCB Lyon1), Villeurbanne, France; Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland. Electronic address: lyndon.emsley@epfl.ch.
authors.forename: Lyndon
authors.initials: L
authors.lastname: Emsley
mesh_terms: D000465:Algorithms; D002244:Carbon / Q000737:chemistry; D002482:Cellulose / Q000031:analogs & derivatives / Q000737:chemistry; D002626:Chemistry, Pharmaceutical; D003692:Delayed-Action Preparations; D005079:Excipients; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D011108:Polymers / Q000737:chemistry*
chemical_list: D003692:Delayed-Action Preparations; D005079:Excipients; D011108:Polymers; D002244:Carbon; C013517:ethyl cellulose; D002482:Cellulose; C008079:hydroxypropylcellulose; C109691:microcrystalline cellulose
keywords: Cellulose; Domain sizes; Solid-state NMR; Spin diffusion