Design and In Vitro Evaluation of Cross-Linked Poly(HEMA)-Pectin Nano-Composites for Targeted Delivery of Potassium Channel Blockers in Cancer Therapy

Abstract

Potassium (K+) channel blockers are promising anticancer agents but suffer from off-target toxicities. We designed cross-linked poly-2-Hydroxyethyl methacrylate (HEMA)–pectin nanogels (HPN) to deliver two model blockers—dofetilide (Dof) and azimilide (Azi)—and evaluated their physicochemical properties, release behavior, and in vitro anticancer activity. HPN was synthesized by surfactant-assisted aqueous nanogel polymerization and comprehensively characterized (FTIR, DLS, TEM/SEM, XRD, BET). The particles were monodispersed with a mean diameter ~230 nm, compatible with tumor accumulation via the Enhanced Permeability and Retention (EPR) effect, and exhibited a microporous matrix suitable for controlled release. Drug loading was higher for Dof than for Azi, with DL% values of 82.30 ± 3.1% and 17.84 ± 2.9%, respectively. Release kinetics diverged: Azi-HPN followed primarily first-order diffusion with a rapid burst, whereas Dof-HPN showed mixed zero/first-order behavior. Cytotoxicity was assessed in A549 lung cancer and BEAS-2B bronchial epithelial cells. Both free and nano-formulated blockers were selectively toxic to A549 with minimal effects on BEAS-2B. Notably, a hormesis-like pattern (low-dose stimulation/high-dose inhibition in MTT) was evident for free Dof and Azi; encapsulation attenuated this effect for Dof but not for Azi. Co-administration with paclitaxel (Ptx) potentiated Dof-HPN cytotoxicity in A549 but did not enhance Azi-HPN, suggesting mechanism-dependent drug-drug interactions. Overall, HPN provides a biocompatible platform that improves K+ blocker delivery.