ABSTRACT
Objective: Optimize to obtain the in situ gel of matrine with thermosensitivity and rectal retention of bioadhesion rectum. Methods: Thermosensitive gel was prepared by cold method, and then using gelation temperature as an indicator, central combination design-response surface method (CCD-RSM) was used to optimize the dosage of P407, P188, and CMC-Na. Texture Analyzer was used to measure the gel strength and adhesion of prescription, the rectal retention was investigated by rectal administration, and the release rate was explored by modified paddle method. Results: The optimal prescription was matrine 2%, CMC-Na 1.0%, P188 1.3%, P407 16.5%, and benzalkonium bromide 0.02%. The prescription gel did not leak after rectal administration in rats, which can remain in the body for more than 6 h, in vitro release in line with Weibull model. Conclusion: The optimized matrine-loaded thermosensitive in situ gel could meet the requirement of rectal administration.