In this study, itaconic acid (IA) was grafted on poly(vinyl alcohol) (PVA) at two different grafting percentages, 7.0% (w/w) and 14.0% (w/w), and membranes were prepared from the grafted copolymer (PVA-g-IA). Performances of PVA and PVA-g-IA membranes for the transdermal release of salicylic acid (SA) at in vitro conditions were investigated by using 2.0 mg/mL SA solutions. Effect of the pH on the release of SA was studied by keeping pH of donor and acceptor solutions in a range of (2.1-7.4). Permeation studies were also carried on at different SA concentrations. Effect of temperature on the release of SA was investigated in the temperature range of (32-39) (61)8C. Results showed that presence of IA decreased the release of SA from the PVA membranes and 73% SA was released at the end of 48 h at (32 6 1)8C from the IA-1 membranes. pH affected the release of SA through the grafted membranes and studies showed that release of SA was high with donor solution pH of 2.1. When the pH of donor and receiver solutions were kept at the same pH value, the overall SA% in permeate increased. Increase in concentration of SA decreased the release of SA for the studied membranes. Release of SA from PVA-g-IA membranes was temperature sensitive and increase in temperature from (32 6 1)8C to (39 6 1)8C increased the release percentage of SA by 24% (w/w). The overall activation energy for the permeation of SA through IA-1 membrane was found to be 22.97 kJ/mol.

In this study, acrylamide (AAm) was grafted onto poly(vinyl alcohol) (PVA) in solution with UV radiation, and membranes were prepared from the graft copolymer (PVA-g-AAm) for transdermal release of salicylic acid (SA) at in vitro conditions. Permeation studies were carried out using a Franz-type diffusion cell. Release characteristics of SA through PVA and PVA-g-AAm membranes were studied using 2.0 mg/mL SA solutions. Effects of the presence of AAm in the copolymer, pH of donor and acceptor solution, and concentration of SA and temperature on the release of SA were investigated. Permeation of SA through the membranes was found to be pH-dependent, and increase in pH generally increased the release percentage of SA, and the presence of AAm in the membrane positively affected the permeation. The effect of concentrations of SA on the permeation was also searched using saturated solution of SA, and permeated amount of SA was found to be less than in the case of unsaturated SA solution. Studies showed that the release of SA from PVA-g-AAm membranes was temperature-sensitive and increase in temperature increased the permeation rate. 82.76% (w/w) SA was released at the end of 24 h at (39 6 1)8C, and the overall activation energy for the permeation of SA through PVA-g-AAm membranes was found to be 19.65 kJ/mol.