OBJECTIVE  This study aimed to explore the optimal process for preparing long-acting liposomes loaded with cockroach extract (CE-Lip) and to evaluate their therapeutic efficacy against ulcerative colitis (UC).

  METHODS  The CE-Lip was prepared using a thin film dispersion method. Orthogonal experiments were conducted to optimize the formulation and freeze-drying process of CE-Lip. Morphological characterization and in vitro release rate assessment were performed. The therapeutic efficacy of CE-Lip was evaluated using a mouse model of UC.

  RESULTS  The optimal preparation process involved a cholesterol-phospholipid mass ratio of 1 ∶ 5, an extract-phospholipid mass ratio of 1 ∶ 4, hydration time of 0.75 h, hydration volume of 3 mL, and hydration temperature of 30 ℃. The optimal freeze-drying process utilized a mixture of 5% mannitol and 10% trehalose as protective agents. The resulting CE-Lip exhibited an average particle size of (276.7±5.6) nm, with a vesicular structure. The stability of CE-Lip after freeze-drying was excellent, and its in vitro release rate was significantly lower than that of the raw material. Pharmacological results demonstrated that CE-Lip significantly reduced DAI scores, colon length, CMDI scores, TNF-α expression, and HS scores in UC mice, while increasing EGF expression and mucin expression in goblet cells.

  CONCLUSION  A simple, stable, and reproducible process for preparing CE-Lip is established. The resulting CE-Lip exhibits uniform size distribution, good stability, and sustained release effects. Compared to conventional formulations, CE-Lip significantly enhanced the therapeutic effect of CE against UC in mice. This study provides a foundation for further development and research of CE-Lip.