In vitro controlled release of 5-aminosalicylate from ZnAl-NO3(-CO3) layered double hydroxide drug delivery system

In the field of pharmaceutical research and development, the development of nano drug carriers based on intercalation structures has become one of the important development directions. Hydrotalcite (LDHs) and its derivatives have the advantages of low cost, simple synthesis, high drug loading efficiency, good biocompatibility, and easy degradation, and have received widespread attention in the field of biomedicine. Based on this, we synthesized 5-aminosalicylate (5-ASA) intercalated NO 3 based and CO 3 based ZnAl-LDHs drug delivery systems using ion-exchange and chemical co-precipitation methods, respectively. The crystalline structure, morphology, thermal stability, and host-guest interaction were characterized in detail by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Ultraviolet visible spectroscopy (UV), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA) and X-ray photoelectron spectroscopic (XPS). The drug loading, drug release behavior and release kinetic of 5-ASA intercalated ZnAl-LDHs were studied. The characterization results indicated that the intercalation mode of the drug and the strength of the host-guest interaction are related to the interlayer anion type and synthesis process of ZnAl-LDHs. The amount of 5-ASA loaded into LDHs from an ion-exchange process was 28.6 and 13.8 wt% for NO 3 − and CO 3 2− based LDHs, respectively, whereas it was 6.9 and 10.4 wt% for co-precipitation process. The modeling kinetics results indicated that the release process of 5-ASA by ZnAl-LDHs intercalated with 5-ASA conforms to the parabolic diffusion model. These results indicated that the drug delivery system was controlled by diffusion of 5-ASA ions into aqueous solution through exchange with phosphate anions.