Therapeutic application of injectable thermosensitive hydrogel in preventing local breast cancer recurrence and improving incision wound healing in a mouse model.

Many drug delivery systems (DDSs) have been investigated for local targeting of malignant disease with the intention of increasing anti-tumor activity and minimizing systemic toxicity. An injectable thermosensitive hydrogel was applied to prevent locoregional recurrence of 4T1 breast cancer in a mouse model. The presented hydrogel, which is based on poly(ethyleneglycol)-poly(ε-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE), flows freely at normal temperature, forms a gel within seconds in situ at body temperature, and eventually releases the drug in a consistent and sustained fashion as it gradually biodegrades. Locoregional recurrence after primary tumor removal was significantly inhibited in mice treated with the paclitaxel (PTX)-loaded PECE hydrogel subcutaneously (9.1%) administered, compared with the blank hydrogel (80.0%), systemic (77.8%) and locally (75.0%) administered PTX, and the control group (100%) (P < 0.01). In addition, tensile strength measurements of the surgical incisions showed that the PECE hydrogel accelerates wound healing at postoperative day 7 (P < 0.05), and days 4 and 14 (P > 0.05), in agreement with histopathological examinations. This novel DDSs represents a promising approach for local adjuvant therapy in malignant disease.