Release of paeonol-β-CD complex from thermo-sensitive poly(N-isopropylacrylamide) hydrogels

• Published in: International journal of pharmaceutics Vol. 402; no. 1; pp. 123 - 128
• Main Authors: Tsao, Jung-Ying, Tsai, Hsieh-Ho, Wu, Chien-Pang, Lin, Pi-Yun, Su, Shan-Yu, Chen, Lieh-Der, Tsai, Fuu-Jen, Tsai, Yuhsin
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.12.2010; Elsevier
• Subjects: Acetophenones - administration & dosage; Acetophenones - chemistry; Acrylic Resins - chemistry; beta-Cyclodextrins - chemistry; Biological and medical sciences; Calorimetry, Differential Scanning; Chemical Precipitation; Cross-Linking Reagents - chemistry; Cyclodextrin; Drug Carriers - chemistry; General pharmacology; Hydrogels; Inclusion complex; Medical sciences; Paeonol; Pharmaceutical technology. Pharmaceutical industry; Pharmacology. Drug treatments; Poly(N-isopropylacrylamide); Release; Temperature; X-Ray Diffraction; Cyclodextrin; Paeonol; Poly(N-isopropylacrylamide); Release; Inclusion complex; Colloidal gel; Pharmaceutical technology; Dosage form; Oside polymer; Hydrogel; Inclusion compound; Acrylamide derivative polymer
• ISSN: 0378-5173; 1873-3476
• DOI: 10.1016/j.ijpharm.2010.09.033

As three-dimensional, cross-linked networks of water-solublepolymers, hydrogels can be made from a water-soluble polymer, encompassing a wide range of chemical compositions and bulk physical properties. By preparing an inclusion complex of paeonol (PAE) with β-cyclodextrin (β-CD), this study investigated its release behavior from thermo-sensitive poly(N-isopropylacrylamide) (PNIPAAm) hydrogels. The PAE–β-CD complex was prepared via coprecipitation. According to differential scanning calorimeter (DSC) and X-ray diffraction (XRD) results, the solid PAE–β-CD complex was found in the amorphous state, indicating that each PAE molecule was encapsulated by a β-CD molecule. The change of chemical shifts of H3 and H5 in proton nuclear magnetic resonance (H NMR) spectra indicated that PAE was inside the CD cavity. PNIPAAm hydrogels containing different cross-linker contents were then synthesized and had a similar lowest critical solution temperature (LCST) of around 33 °C. Experimental results of swelling and deswelling indicated that increasing the cross-linker content of the hydrogel decreased the swelling ratio and increased the water retention. According to experimental results of PAE–β-CD complex release, the release rate at 45 °C (>LCST) was higher than at 25 °C (<LCST). Moreover a lower cross-linker content the hydrogel contained implies a higher rate of PAE–β-CD complex release. Above results suggest that the release of PAE–β-CD complex is related to the volume contraction of the hydrogel, which is affected by hydrogel compositions and release temperatures.