Biodegradable polysaccharide aerogels based on tragacanth and alginate as novel drug delivery systems

Tragacanth, an anionic polysaccharide, is a natural material widely investigated for the synthesis of aerogels as drug delivery vehicles. Its biocompatibility, biodegradability, and affordability are all key features for its use in pharmaceutical applications. In this study, tragacanth and tragacanth alginate composite aerogels were prepared using the sol-gel technique followed by supercritical drying. Paracetamol was selected as a model drug for drug loading and release studies owing to its high solubility in ethanol and low solubility in supercritical carbon dioxide. The paracetamol loading into the aerogel pores was confirmed by infrared spectroscopy (IR) and x-ray diffraction (XRD) spectra of the resulting samples. Scanning electron microscopy (SEM) images showed that all aerogels were porous with a macroporous-mesoporous network. Due to the high porosity of the prepared aerogels, a loading of 99 wt% (mg drug/mg aerogel) for tragacanth and 114 wt% (mg drug/mg aerogel) for composite aerogels was achieved. Moreover, the release rate of the drug could be modified by manipulating the aerogel composition. Tragacanth aerogels had a faster release rate, while the addition of alginate prolonged the release rate of the model drug. Various empirical release models were investigated and the release rate was found to follow the Korsmeyer-Peppas (Power Law) model suggesting a diffusion-based release kinetics. Based on the results, the feasibility of utilizing tragacanth for the preparation of drug-loaded aerogels was shown. Graphical Abstract