A novel peptide from Periplaneta americana: Development of a long-acting formulation for ulcerative colitis therapy.

Ulcerative colitis (UC) brings a heavy burden to patients due to its long course, difficulty in cure, high relapse rate, and high carcinoma rate. Limitations of conventional drugs, including poor compliance and high recurrence, are now being addressed by modern approaches like immune-modulating therapies and refined surgical techniques. Therefore, there is an urgent clinical need for a new therapeutic strategy that is safe, long-acting, and has good compliance. In this study, we extracted and fractionated an peptide PAE-P6 with significant anti-inflammatory activity from Periplaneta americana extract (PAE), and it showed certain therapeutic effect in UC mice. To enhance the efficacy and stability of peptides in vivo, we further developed this peptide into a long-acting thermosensitive liposome gel formulation. Following rectal administration, this formulation demonstrated remarkable efficacy in a mouse model of UC by boosting the expression of anti-inflammatory factors, repairing tight junctions, regenerating mucin, and inhibiting the expression of pro-inflammatory factors. This study offers a promising strategy for targeted and sustained drug delivery in UC treatment.