Elucidation of two water leachable polymers impact on microporous membrane performance and drug permeation

The influence of two water-leachable pore-forming agents, polyvinylpyrrolidone (PVP) and poly(ethylene glycol) (PEG), on the performance of cellulose acetate (CA) microporous membranes was elucidated. Various compositions of CA/PVP and CA/PEG blended membranes were prepared and characterized by Fourier transform infrared (FTIR) spectroscope and differential scanning calorimetry (DSC). The FTIR data indicated the presence of interaction between CA and pore-forming agent via a hydrogen bond. The DSC thermal data implied that CA and PEG presented as two separated phases in the blended membranes. However, CA and PVP were miscible at the blended compositions. The extent of miscibility between CA and pore-forming agents dominated the leach degree of the latter. The microporous membranes prepared by solvent–casting–leaching showed that PEG was completely leached from CA/PEG blended membranes regardless of its initial blending level. On the contrary, the leach of PVP was dependent of the initial composition of CA/PVP blended membranes. The permeation of theophylline from CA/PEG microporous membranes was much faster than from CA/PVP ones especially when blending 40–50% pore-forming agent. Although the porosities of CA50%/PVP50% and CA50%/PEG50% microporous membranes were similar, less tortuosity and more interconnected channels in terms of higher ɛ/τ value of CA50%/PEG50% microporous membrane resulted in the highest drug permeation. The permeation of theophylline through CA microporous membranes showed a good linear correlation with the ɛ/τ values of all microporous membranes (r2 = 0.994).