Characteristics of waterborne Polyurethane/Poly(N-vinylpyrrolidone) composite films for wound-healing dressings

For ideal wound-healing dressings, a series of waterborne polyurethane (WBPU)/poIy(N-vinylpyrrolidone) (PVP) composite films (transparent film dressings) were prepared by in situ polymerization in an aqueous medium. Stable WBPU/PVP composites, which had a high remaining weight greater than 98.4%, were obtained. The maximum content of PVP for stable WBPU/PVP dispersions was found to be about 15 wt %. The water absorption (%) and equilibrium water content (%) of the WBPU/ PVP composite films remarkably increased in proportion to the PVP content and the time of water immersion. The maximum water absorption and equilibrium water content of the WBPU/PVP composite films were in the range of 21-158 and 22-56%, respectively. The water vapor transmission rate of the WBPU/PVP composite films was in the range of 1816-2728 g/m(2)/day. These results suggest that WBPU/PVP composite films may have high potential as new wound-dressing materials that provide and maintain the moist environment needed to prevent scab formation and dehydration of the wound bed. By a wound-healing evaluation using a full-thickness rat model experiment, it was found that a wound covered with a typical WBPU/ PVP composite film (15 wt % PVP) was completely filled with new epithelium without any significant adverse reactions. (C) 2007 Wiley Periodicals, Inc.