Huperzine A, Enteric Sustained Release Tablets

Huperzine A is a powerful selective inhibitor of acetylcholinesterase and an effective component of the Chinese traditional medicines, which has good therapeutic effect on clinical therapy to the alzheimer's disease.HPLC method was applied to determinate preparation content, drug release, related substances and drug concentration in vivo. The method was sensitive and accurate which could meet the requirement of the analysis.The absorption sites and kinetics were studied from various intestinal segments' ligations using recirculating perfusion method in rats. The result demonstrated that two drugs had similar absorptive feature: better absorption in the small intestine and no special absorption site. The mechanism of the intestinal absorption about both drugs was the passive diffusion.Huperzine A sustained released tablet of daily administration was designed and prepared by using hydroxypropyl methylcellulose (HPMC) as basic matrix material. On the basis of single-factor tests about prescription and techniques, huperzine A sustained released tablet was designed and prepared according to addenda XIXD of CHP2005 and the quality criteria of tablets was established. By analysis of release data using different equations, huperzine A released by diffusion combined with erosion from HPMC matrix, and erosion release played an important role.Stability studies of preparation were shown that light and moisture had little effect, but moisture resistant should be paid attention; and temperature had more effect on the preparation, so it was necessary that the preparation was stocked in cool place.The relative bioavailability and pharmacokinetics studies of huperzine A were performed in six healthy dogs, using ordinary tablets as the reference. The HPLC method was developed for determining huperzine A in dog plasma. T_max of huperzine A in self-made tablets and reference tablets were 9.33±1.63 h, 3±0.92 h, respectively; C_max were 1.95±0.29 ng/ml,6.23±0.91 ng/ml; AUC_0-t were 28.29±2.03 ng·h /ml,27.45±1.83 ng·h /ml,...