Preparation and in-vitro release of chlorothiazide novel pH-sensitive chitosan-N,N′-dimethylacrylamide semi-interpenetrating network microspheres

pH-sensitive novel semi-interpenetrating networks (semi-IPN) of N,N′-dimethylacrylamide (NNDMA) and chitosan (CS) were prepared in the form of microspheres by water-in-oil (w/o) emulsion technique. Microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and X-ray diffractometry (X-RD) technique to confirm the crosslinking as well as polymorphism of chlorothiazide (CLT) drug. X-RD and DSC techniques indicated molecular level dispersion of CLT in the IPN matrix. Scanning electron micrographs (SEM) of the microspheres indicated smooth surfaces of the spherical microspheres. Cumulative release characteristics of the matrices for CLT, anti-hypertensive drug, were investigated in pH 1.2 and 7.4 media. Particle size and size distribution of the microspheres was measured by dynamic laser light diffraction technique. It was possible to release CLT in a controlled manner up to 12 h.