title: Effect of PVP K-25 on the formation of the naproxen:beta-ciclodextrin complex.
abstract: The aim of this study was to investigate the effects of the presence of the water-soluble polymer polyvinylpyrrolidone K-25 (MW=24000g/mol) on the complexation of the AINE naproxen, in its sodium salt form, with the beta-cyclodextrin. The data revealed that the polyvinylpyrrolidone K-25 interacts with the drug as well as with the drug:beta-cyclodextrin inclusion complex. The polymer shows more affinity for the inclusion complex, K=(6.67+/-0.292) x 10(-5)M(-1) than for the free drug, (2.08+/-0.208) x 10(-5)M(-1). The presence of different proportions of polymer, in a range 0-1% (w/w) of polyvinylpyrrolidone, does not increase the ability of drug-cyclodextrin complexation but important changes in the driving force of complex formation were detected, depending on the percentage of polyvinylpyrrolidone K-25 present. At low polymer concentrations, the complexation process is driven entropically, while at higher PVP proportions it is enthalpically favored. In the ternary system, polyvinylpyrrolidone K-25 partially or totally coats the drug:beta-cyclodextrin inclusion complex interacting with the beta-cyclodextrin (through hydrogen bonds), and with the naproxen.
authors.affiliation: Departamento de Química Física, Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain.
authors.forename: Margarita
authors.initials: M
authors.lastname: Valero
authors.forename: Blanca I
authors.initials: BI
authors.lastname: Pérez-Revuelta
authors.forename: Licesio J
authors.initials: LJ
authors.lastname: Rodríguez
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry*; D004337:Drug Carriers; D005079:Excipients / Q000737:chemistry; D009288:Naproxen / Q000737:chemistry*; D016011:Normal Distribution; D011205:Povidone / Q000737:chemistry*; D012995:Solubility; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water; D047392:beta-Cyclodextrins
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D003505:Cyclodextrins; D004337:Drug Carriers; D005079:Excipients; D012996:Solutions; D047392:beta-Cyclodextrins; D014867:Water; D009288:Naproxen; D011205:Povidone; C031215:betadex