Development and bioavailability testing of an estetrol and estetrol-zinc-containing vaginal hydrogel: a novel hydroxyethyl cellulose and hydroxypropyl-β-cyclodextrin-based formulation

The authors aim to develop a novel hydroxyethyl cellulose-based vaginal hydrogel containing estetrol and estetrol-zinc to improve drug retention, bioavailability, and patient compliance for treating genitourinary syndrome of menopause. Their study demonstrates that the formulation is biocompatible, enhances estetrol solubility, and allows for sustained drug release while minimizing systemic exposure. Future clinical trials are needed to validate the in vivo effectiveness and long-term safety of this hydrogel.