title: Aqueous chromatography system using pH- and temperature-responsive stationary phase with ion-exchange groups.
abstract: We report on the development of a novel analytical HPLC technique of nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, ketoprofen and naproxen, with an isocratic aqueous mobile phase. In this study, we designed a new pH- and temperature-responsive copolymer of N-isopropylacrylamide (NIPAAm), butyl methacrylate (BMA) and N,N-dimethylaminopropylacrylamide (DMAPAAm). The copolymer was modified with cross-linked poly(NIPAAm-co-BMA-co-DMAPAAm) (IBD) hydrogel on to aminopropyl silica beads, and the products were evaluated as HPLC packing materials for an ion-exchange- and temperature-responsive chromatography. The property of the surface of the stationary phase was altered from hydrophilic to hydrophobic, and from charged to non-charged by changes in the temperature and pH. In addition, it is possible that ion-exchange groups can appear or be hidden on the polymer chain surface by temperature changes. The interactions of NSAIDs with this stationary phase were controlled by the temperature and the pH with a constant aqueous mobile phase. PH- and temperature-responsive chromatography is expected to be useful for the separation of pharmaceuticals and biomolecules.
authors.affiliation: Department of Physical Pharmaceutical Chemistry, Kyoritsu University of Pharmacy, Minato-ku, Tokyo, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Ayano
authors.forename: Kyoko
authors.initials: K
authors.lastname: Nambu
authors.forename: Chikako
authors.initials: C
authors.lastname: Sakamoto
authors.forename: Hideko
authors.initials: H
authors.lastname: Kanazawa
authors.forename: Akihiko
authors.initials: A
authors.lastname: Kikuchi
authors.forename: Teruo
authors.initials: T
authors.lastname: Okano
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins / Q000737:chemistry*; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000302:isolation & purification; D001554:Benzene / Q000302:isolation & purification; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003348:Cortisone / Q000302:isolation & purification; D003907:Dexamethasone / Q000302:isolation & purification; D006854:Hydrocortisone / Q000031:analogs & derivatives / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D008689:Methacrylates / Q000737:chemistry*; D011241:Prednisone / Q000302:isolation & purification; D012822:Silicon Dioxide; D013696:Temperature; D013739:Testosterone / Q000302:isolation & purification
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D000894:Anti-Inflammatory Agents, Non-Steroidal; D008689:Methacrylates; C513218:poly(N-isopropylacrylamide-co-butyl methacrylate-co-N,N-dimethylaminopropylacrylamide); C052970:poly-N-isopropylacrylamide; C021650:hydrocortisone acetate; D013739:Testosterone; D012822:Silicon Dioxide; D003907:Dexamethasone; D001554:Benzene; D003348:Cortisone; D011241:Prednisone; D006854:Hydrocortisone