Sodium alginate/poly(4-vinylpyridine) polyelectrolyte multilayer films: Preparation, characterization and...

Polyelectrolyte multilayer (PEC) films of sodium alginate (Na-Alg) and poly(4-vinylpyridine) (P₄VP) were prepared and were loaded with an antibacterial agent, ciprofloxacin HCl (CIP.HCl) aiming to design new hydrophilic films with controlled physicochemical properties and drug release behaviour that may find application as components of transdermal drug delivery systems. The PEC films were characterized by SEM, XRD, TGA, AFM and FTIR spectroscopy. The hydrophilicity of the PEC films was examined by using contact angle measurement. The number of layers and the nature of the outer layer affect the physicochemical characteristics, CIP.HCl loading and release behaviour of the films. The three layer film PEC-3, which is composed of Na-Alg outer layer deposited on a P₄VP/Na-Alg double layer, is characterized by the lowest roughness (Rq = 16.3 nm) and the most hydrophilic surface with a contact angle value of 38.1° among all other films. Its crystallinity index is 0.36, and starts to degrade at 195 °C. It exhibits 130-135% equilibrium swelling capacity in acid buffer and water respectively. PEC-3 is the film with the highest drug loading capacity and drug loading efficiency values of 3.51% and 87% respectively. A cumulative drug release of 65% is obtained from PEC-3 within 24 h in pH = 1.2 buffer solution.