title: Tetramethylpyrazine-Loaded Hydrogels: Preparation, Penetration Through a Subcutaneous-Mucous-Membrane Model, and a Molecular Dynamics Simulation.
abstract: Tetramethylpyrazine (TMP) was extracted from Ligusticum chuanxiong hort. The compound is known to have a variety of medicinal functions; in particular, it is used for the treatment of cerebral ischemic diseases. TMP-loaded hydrogels offer an excellent preparation with the capacity to bypass the blood-brain barrier, allowing treatment of the brain through intranasal administration. We prepared TMP-loaded hydrogels using carbomer 940 and evaluated the release of TMP from the hydrogel. We determined the release rate using Franz-type diffusion cell experiments with a subcutaneous-mucous-membrane model and also by a molecular dynamics (MD) simulation. In general, the former method was more complicated than the latter was. The dynamic behavior of TMP release from the hydrogel was revealed by analysis of the mean square displacement of the trajectory in the MD simulation. The coefficient of TMP diffusion from the hydrogel was calculated at different temperatures (277, 298, and 310 K) by using MD software. The results showed that the coefficient of diffusion increased with an increase in temperature. This trend was observed both experimentally and in the MD simulation. Therefore, the MD simulation was a complementary method to verify the experimental data.
authors.affiliation: College of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230038, People's Republic of China. sm_shine@163.com.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Xia
authors.affiliation: Zhaoke (Hefei) Pharmaceutical Co. Ltd, Hefei, 230088, People's Republic of China.
authors.forename: Yinxiang
authors.initials: Y
authors.lastname: Xu
authors.affiliation: College of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230038, People's Republic of China.
authors.forename: Zhiqing
authors.initials: Z
authors.lastname: Cheng
authors.affiliation: School of Life Science, University of Science and Technology of China, Hefei, 230027, People's Republic of China.
authors.forename: Yongfeng
authors.initials: Y
authors.lastname: Cheng
mesh_terms: D000818:Animals; D004058:Diffusion; D065546:Drug Liberation; D020100:Hydrogels / Q000737:chemistry; D030004:Ligusticum / Q000737:chemistry; D051379:Mice; D008813:Mice, Inbred ICR; D056004:Molecular Dynamics Simulation; D009092:Mucous Membrane / Q000378:metabolism; D011719:Pyrazines / Q000008:administration & dosage* / Q000737:chemistry; D012867:Skin / Q000378:metabolism
chemical_list: D020100:Hydrogels; D011719:Pyrazines; C017953:tetramethylpyrazine
keywords: Franz-type diffusion cell; carbomer 940; molecular dynamics simulation; release; tetramethylpyrazine (TMP)-loaded hydrogel