Sequential drug release system: Targeting the tumor ECM for enhanced chemotherapy efficacy.

The dense extracellular matrix (ECM) of stroma-rich solid tumors acts as a significant barrier to effective chemotherapy by hindering drug penetration. In this study, a supramolecular hydrogel was successfully developed, enabling the codelivery and sequential release of hydrophilic and lipophilic drugs designed to target the ECM. The hydrogel is easy to prepare, has self-healing properties and excellent biocompatibility. Upon administration, the hydrogel first releases pirfenidone to inhibit collagen production, weakening the ECM, followed by the release of paclitaxel, which improves tumor penetration. The effectiveness of this sequential drug delivery system was validated in both oral squamous cell carcinoma and pancreatic cancer models, a classic example of a tumor with abundant ECM. In vitro experiments showed controlled sequential release profiles, whereas in vivo experiments using cell-derived and patient-derived xenograft models revealed that the hydrogel was more effective at tumor suppression compared to traditional methods. Single administration of the hydrogel led to long-term localized drug release, maintaining higher concentrations of chemotherapeutic agents in the tumor tissue and effectively reducing the tumor volume. This study provided a promising strategy to enhance chemotherapy in ECM-dense tumors, offering an efficient and minimally invasive method for localized, sustained-release cancer therapy.