Delivery of soluble ethinylestradiol complex by pH-responsive core-shell composite hydrogel capsules

Ethinylestradiol (EE) is a potent estrogen widely used to treat diseases such as breast cancer, prostate cancer, and menopausal syndrome. The poor aqueous solubility of EE leads to erratic oral absorption, resulting in suboptimal plasma levels. Developing a formulation to enhance the solubility of EE in the gastrointestinal tract would be beneficial to increase the bioavailability of EE. Thereafter, we prepare diethylenetriamine-β-cyclodextrin/ethinylestradiol (DETA-β-CD/EE) complex, aiming to increase the solubility of EE in water, and design and prepare core-shell composite hydrogel capsules with aldocellulose and hydroxyethyl cellulose as the core and sodium alginate as the shell. The stability, swelling, drug release behavior and biocompatibility of the core-shell hydrogel capsules are carefully investigated. And the results show that the prepared hydrogel capsules have the controlled and sustained release ability of soluble DETA-β-CD/EE, can achieve pH-responding to intestinal fluid, and are non-toxic to normal human cells.