Study on inclusion behavior and properties of tetrahydropalmatine with β-cyclodextrin and its derivatives / 中草药

ABSTRACT

Objective: To prepare tetrahydropalmatine (THP) and β-cyclodextrin (β-CD) and its derivatives inclusion complexes (HP-β-CD, DM-β-CD, and TM-β-CD and explore their inclusion behavior and properties. Methods: The inclusion complexes of THP with β-CD, HP-β-CD, DM-β-CD, and TM-β-CD were prepared by saturated solution. The inclusion ratio and stability constant of inclusion complexes were determined with the Job plot and UV-vis spectroscopy. The THP/CDs complexes were characterized and determinated by means of XRD, TG, and SEM. The molecular simulation was processed to investigate the inclusion behavior of THP and different CDs. The water solubility of the inclusion complexes was measured and the stability test was conducted in the simulated human gastric juice and intestinal fluid environment. Results: Job plot and UV-vis spectroscopy showed that inclusion ratio of host-guest inclusion complexes was 11. Molecular docking showed that the entire THP entered the macrophage port and run through the cavities of β-CD and DM-β-CD, with the two aromatic rings located at the large and small mouth, respectively. For HP-β-CD and TM-β-CD, the two nitrogen heterocycle of THP were “V” shaped inlaid into the CD cavity, and both aromatic rings were located at the large end of the CDs. Conclusion: The solubility of tetrahydropalmatine was increased from 0.30 mg/mL to 1.60, 3.40, 9.13, and 4.02 mg/mL for β-CD, HP-β-CD, DM-β-CD, and TM-β-CD, respectively. The thermal stability and biological environment stability had been significantly improved.