Abstract
The supramolecule has been paid much attention recently to form functional structures by the inter- and/or intra-molecular interactions. According to our previous research, it was found that the PVA solution forms the elastic and flexible hydrogel by ultra-high pressure treatment. The PVA nanospheres or nanoaggregates were also obtained by changing the treatment condition. In order to investigate the release properties of PVA hydrogels prepared by ultra-high pressure treatment, we used α-G Hesperidin and Oil Blue N as a water-soluble and an oil-soluble model drug, respectively. These model drugs were mixed with PVA solution and were treated under ultra-high pressure. In the case of oil-soluble drug, Oil Blue N was mixed with dodecane, and O/W emulsion was prepared by using a homogenizer before the treatment. The sustained release experiment was carried out by immersing the PVA hydrogels in ultra-pure water (water-soluble drug), or in the mixture solution of ethanol and water (oil-soluble drug). In the case of oil-soluble drug, the diameters of dodecane droplets in PVA hydrogels showed no change by ultra-high pressure treatment. The property of sustained release was discussed by Higuchi Plot. In the case of oil-soluble drug, the release rate was unchanged in spite that the operation conditions were varied in a wide range. The content of ethanol in the solution significantly affected the release rate. Whereas, in the case of water-soluble drug, especially in 5 w/v% PVA solution, the release rate slightly depended on the crosslinking degrees of PVA hydrogels. That is, we controlled the sustained release rate by changing the condition of the ultra-high pressure treatment.
