A Comparison of Drug Delivery Systems of Zr-Based MOFs and Halloysite Nanotubes: Evaluation of beta-Estradiol Encapsulation

The low cytotoxic Zr-based MOF PCN-221, which exhibited the ability to entrap beta-estradiol model drug, was studied as a drug delivery system. As a comparison, another drug carrier, halloysite nanotubes, was also investigated. Both PCN-221 and halloysite nanotubes were characterized by IR spectroscopy, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM). beta-estradiol was loaded mainly on skeleton and partially on the external surface of PCN-221. We show that controlled release of beta-estradiol from PCN-221 was observed over more than 31 days, compared with the 20 days release period from halloysite nanotubes, indicating PCN-221 are a superior carriers of beta-estradiol.