Ternary naproxen:β-cyclodextrin:polyethylene: glycol complex formation
[EN]The aim of this study was to investigate the effect of the presence of the water-soluble polymer polyethylene glycol (PEG)—MW=35000 g/mol—on the complexation of the phototoxic anti-inflammatory drug naproxen, in its sodium salt form, with β-cyclodextrin (β-CD). The data revealed that the polymer...
| Authors: | , , |
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| Format: | article |
| Status: | Published version |
| Publication Date: | 2003 |
| Country: | España |
| Institution: | Universidad de Salamanca (USAL) |
| Repository: | GREDOS. Repositorio Institucional de la Universidad de Salamanca |
| OAI Identifier: | oai:dnet:gredos______::d22b5b4552cd259b2c010e91268cd7fc |
| Online Access: | http://hdl.handle.net/10366/171030 |
| Access Level: | Open access |
| Keyword: | Naproxen Polyethylene glycol β-cyclodextrin Polyethylene Glycols glicoles de polietileno naproxeno |
| Summary: | [EN]The aim of this study was to investigate the effect of the presence of the water-soluble polymer polyethylene glycol (PEG)—MW=35000 g/mol—on the complexation of the phototoxic anti-inflammatory drug naproxen, in its sodium salt form, with β-cyclodextrin (β-CD). The data revealed that the polymer does not interact with the uncomplexed naproxen whereas it does with the β-CD. The presence of different proportions of PEG, in the 0–1% (w/w) range, systematically lowers Kapp of the formation of the naproxen:β-CD inclusion complex. The reason for the decrease in the complexed drug is the presence of other competing equilibria, the first one is an interaction of the polymer with the β-CD, which in turn reduces the amount of free CD available for including the naproxen, and the second is the formation of a naproxen:β-CD:PEG ternary complex with lower affinity than the binary complex. The binding constant of these processes are K2=(4.5±1.0)×105 M−1 and K3=870±19 M−1, respectively. In addition the presence of the PEG produces an important change in the driving force of the complex formation. In this case the process is enthalpically unfavoured and entropically favoured; these are typical characteristics of processes governed by hydrophobic interactions. |
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