pH-Sensitive Polymeric Systems for Controlling Drug Release in Nocturnal Asthma Treatment

The aim of our study was to design pH-sensitive pulsatile drug delivery system which exposes a pulsed release of drug. Polyacrylic acid (PAA) is a pH-responsive weak polyelectrolyte polymer that exhibits a highly coiled conformation at low pH but a highly extended state at high pH. Binary blends of PAA and ethylcellulose (EC) with different ratios were used for coatings as pH sensitive polymeric systems efficiently controlling the release of drug from the coated film through a design of pulsed release with some pause intervals. Imaging analyses using scanning electron microscopy, near-infrared imaging, confocal laser scanning microscopy, and Fourier transform infrared spectroscopy confirmed the release behavior of the drug and fumaric acid from coated tablets.