Preparation of Eudragit L100 coated silica aerogel filled HPC/CS pH-sensitive composites for sustained release of 5-fluorouracil

The release rate and time are very important for the drug carriers, silica aerogel filled hydroxypropyl cellulose/ chitosan (SA/HPC/CS) composites were fabricated for the release of 5-fluorouracil (5-Fu), and the release rate and time were regulated with the content of SA, pH value and external coating material. Firstly, the 5-Fu loaded SA/HPC/CS composites and Eudragit L100 coated composites were prepared with cross-linking followed by freeze-drying, and characterized by SEM, FTIR, XRD, DSC, and TG. Then, the effect of SA content on the encapsulation efficiency of SA/HPC/CS@5-Fu was investigated, and 5-Fu release behavior under different pH values from these aerogel composites was evaluated with four kinetic models. In addition, to further solve the abrupt effect of the obtained composites, Eudragit L100 coated SA/HPC/CS@5-Fu was fabricated, the sustained release behavior revealed that the coating technique can effectively improve the release behavior and extend release time.