Controlled loading and release of methylene blue for hydrogen-bonded LbL poly(vinyl pyrrolidone)/poly (acrylic acid) film

The layer-by-layer (LbL) assembled multilayer films are widely used in controlled drug delivery. Here, hydrogen-bonded LbL multilayer films were assembled through alternating deposition of poly(vinylpyrrolidone) (PVPON) and poly(acrylic acid) (PAA) on glass slides. Methylene blue (MB) was used as a model drug to investigate the loading and release ability of the prepared multilayer film. The results showed that the loading rate of MB was greatly influenced by pH value of the dye solution, and the release rate was controlled both by ionic strength and pH value of immersing solution. The result also indicated that the loading and release of MB were reversible and can be repeated many times. It suggested that the PVPON/PAA multilayer film had potential applications in drug delivery and controlled release.