Abstract

In the present work gelatin (GT) and lignosulfonic acid (LSA) blend microspheres were developed by crosslinking
with glutaraldehyde (GA). Pyronaridine an antimalarial agent was loaded into these microspheres. Various
formulations were prepared by varying ratios of GT/LSA, GA and % pyronaridine loading. Microspheres were
characterized by Fourier transforms infrared (FT-IR) spectroscopy, differential scanning calorimetric, X-ray
diffraction (X-RD) and scanning electron microscopy (SEM). FT-IR spectroscopy confirmed the crosslinking and
presence of drug in the GT/LSA microspheres. X-RD studies were performed to understand the crystalline nature
of drug after encapsulation into interpenetrating polymer network (IPN) microspheres. SEM images gave the
beads with smooth surface. Drug release profiles of the IPN microspheres at pH 1.2 and 7.4 confirmed that
the microspheres formed are pH-sensitive, resulting in controlled release of drug during in vitro dissolution
experiments. It has been analyzed with an empirical equation to understand the diffusion nature of drug through
the GT/LSA microspheres. Both encapsulation efficiency and release patterns are found to be dependent on the
nature of the cross-linking agent as well as amount of drug loading and percentage of GT/LSA microspheres. In
vitro release studies indicated that the microspheres enhance the release rates of pyronaridine drug up to 10 h.