title: [Study on the release and mechanism of carbon nanotubes loaded with verapamil hydrochloride in vitro].
abstract: OBJECTIVE
  The aim of this study was to load Verapamil Hydrochloride to carboxylated multi-walled carbon nanotubes( c-CNTs) and discuss the mechanism of drug release which could act as an effective basis for c-MWNTs used as drug carriers of controlled and sustained release delivery system.
  
  
  METHODS
  Raw CNTs were treated with mixed strong acid to obtain c-CNTs. Raman, IR, SEM and HR-TEM were used to characterize the CNTs and investigate the loading sites for drugs. The release behavior of the drug delivery system in vitro and the release model were studied.
  
  
  RESULTS
  The raw CNTs were successfully grafted with carboxyl group by acid treatment. The water-soluble ability of c-CNTs was greatly improved. The length of c-CNTs was 200-300nm. Meanwhile, the ends of c-CNTs were opened. The results of the drug loading experiment showed that the more adding drugs, the larger loading content of drugs. Most of the drugs were loaded into the inner pores of c-CNTs when adding drugs was no more than 0.1 as quantity as c-CNTs. As the quantity of adding drugs increased, the drugs were loaded both in the inner pores and on the out-wall of c-CNTs. The release results in vitro showed release mechanism had something with the quantity of adding drugs.
  
  
  CONCLUSIONS
  C-CNTs can be used as carriers of sustained and controlled release delivery system. Ideal release behavior of drugs can be achieved by choosing appropriate formula.
authors: Gansu Province Hospital of TCM, Lanzhou 730050, China. zhiziangel@163.com
authors: Jiu
authors: J
authors: Wang
authors: Ya-jing
authors: YJ
authors: Wang
authors: Ran
authors: R
authors: Ran
authors: Yuan-fen
authors: YF
authors: Liu
authors: Chun-li
authors: CL
authors: Zheng
authors: Li-qun
authors: LQ
authors: Jiang
authors: Jia-bi
authors: JB
authors: Zhu
mesh_terms: D003692:Delayed-Action Preparations; D004337:Drug Carriers / Q000737:chemistry*; D005240:Feasibility Studies; D006863:Hydrogen-Ion Concentration; D046529:Microscopy, Electron, Transmission; D036103:Nanotechnology / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D012995:Solubility; D013696:Temperature; D014700:Verapamil / Q000008:administration & dosage* / Q000737:chemistry* / Q000378:metabolism
chemical_list: D003692:Delayed-Action Preparations; D004337:Drug Carriers; D037742:Nanotubes, Carbon; D014700:Verapamil