Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2487472 | Journal of Pharmaceutical Sciences | 2008 | 11 Pages |
Abstract
The effect of physical crossâlinking was studied on the formation and properties of thermosensitive polymer particles of poly(Nâvinylcaprolactam), PVCL, and PVCL grafted with poly(ethylene oxide) macromonomer, PVCLâgraftâC11EO42. Loading and release of model drugs into/from the hydrogel particles were evaluated. Thermosensitive particles were stabilized by crossâlinkers, the most feasible of which was salicylic acid (SA). At 23°C, below the lower critical solution temperature (LCST) of the thermosensitive polymers, stability of the hydrogels was poor, whereas at 37°C stable hydrogel particles were formed. All the drugs and also the crossâlinker (SA) were released more efficiently from the PVCL particles compared to the PVCLâgraftâC11EO42 particles. Drug concentration and pH affected clearly the rate and extent of drug release in physiological buffer. The higher drug release from the PVCL was based on the more open gelâlike structure as opposed to PVCLâgraftâC11EO42 particles. Complex formation between the crossâlinker and the polymers was due to the hydrogen bonding between the hydroxyl groups of SA and Hâbond acceptors of the PVCL. In the case of PVCLâgraftâC11EO42, the ethylene oxide chain provided more opportunities for Hâbonding in comparison to the pure PVCL, creating more stable complexes (more tightly packed particles) leading to sustained drug release.
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Authors
Henna Vihola, Antti Laukkanen, Heikki Tenhu, Jouni Hirvonen,