QCM-D study of layer-by-layer assembly of polyelectrolyte blend films and their drug loading-release behavior

Preparation of multilayered polyelectrolyte and polyelectrolyte blend films and their drug uptake/release properties are studied using quartz crystal microbalance-dissipation (QCM-D). Polyvinylamine hydrochloride (PVA), polystyrene sulfonate sodium salt (PSS), and polyacrylic acid (PAA) were used as polyelectrolytes. Either films of the pure polyelectrolytes (PVA/PSS and PVA/PAA) or blends (PVA/PAA–PSS) were used. Our studies indicate that multilayer growth and drug loading/release properties of ibuprofen (IBF) can be successfully followed using QCM-D. Simultaneous UV–vis and QCM-D studies also show that the blend composition of the films always differs from the mixture composition of the dipping solution independent of pH of the dipping solutions. While PAA is more adsorbed at pH 5.5, PSS is almost completely adsorbed at pH 1.7. On the other hand, it is found that the films prepared from polyelectrolytes at pH 1.7 without salt are stable in neutral and acidic pH, while the lbl blend films prepared at pH 5.5 with or without salt decompose at pH 2 and 11. Pure PVA/PAA films exhibit a faster release of IBF than those of pure PVA/PSS and blend films due to the fact that the pH probably triggered a burst disintegration. IBF release characteristics of blend films differ from pure systems and a two-step release behavior is observed. It is emphasized that hydrogen bonding between PAA and IBF has an important role for the retarded IBF release from the blend films if PSS lead to hydrophobic interactions with the drug. In conclusion, pH stimuli lbl assembled films are prepared and their drug loading/release can be fine-tuned depending on multilayer structure.