title: Characterization and Bioavailability Study of Baicalin-mesoporous Carbon Nanopowder Solid Dispersion.
abstract: BACKGROUND
  Baicalin is the main bioactive constitute of the dried roots ofScutellaria baicalensisand possesses various biological activities. However, the poor water solubility and low oral bioavailability limit its efficacy.
  
  
  OBJECTIVE
  The present study was conducted to enhance the dissolution and oral bioavailability of baicalin (BA) through a novel mesoporous carbon nanopowder (MCN) drug carrier.
  
  
  METHODS
  Solid dispersions (SDs) of BA with MCN were prepared using a solvent evaporation method. The physical state of the formulations was investigated using SEM, differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). The pharmaceutical performance of pure BA, physical mixture (PM) and SDs was evaluated by performing anin-vitrodissolution test. The pharmacokinetic studies were conducted in SD rats and the analysis of the biological samples was performed on an Acquity UPLC-MS system. The intestinal and renal toxicity test of MCN was also evaluated.
  
  
  RESULTS
  The drug release profile indicated that the BA dissolution rate from SDs with a BA/MCN ratio of 1:6 greatly increased in comparison with that of the pure crystalline drug. Furthermore, a pharmacokinetic analysis in rats showed that the BA area under the concentration-time curve for SDs of MCN/BA was 1.83 times larger than that of pure BA. In comparison with the pure drug, the MCN-BA system significantly shortened the time toTmaxand generated higherCmax. There was no intestinal and renal toxicity of MCN.
  
  
  CONCLUSIONS
  These results indicated that the oral bioavailability of BA was remarkably improved by the MCN carrier. Additionally, intestinal toxicity test showed that MCN produced no toxicity in the gastrointestinal tract. Our results show that MCN-based SDs could be used to enhance the bioavailability of drugs with poor water solubility.
  
  
  CONCLUSIONS
  The drug release profile indicated that the BA dissolution rate from SDs with a BA/MCN ratio of 1:6 greatly increased in comparison with that of the pure crystalline drug.Furthermore, a pharmacokinetic analysis in rats showed that the BA area under the concentration-time curve for SDs of MCN/BA was 1.83 times larger than that of pure BA.In comparison with the pure drug, the MCN-BA system significantly shortened the time toTmaxand generated higherCmaxAbbreviations used:BA: baicalin, MCN: mesoporous carbon nanopowder, SDs: solid dispersions, SEM: scanning electron microscopy, DSC: differential scanning calorimetry, XRD: powder X-ray diffraction, HPLC: high-performance liquid chromatography, PM: physical mixture, S.D.: standard deviation, ANOVA: analysis of variance, RSD: relative standard deviation, ESI: electrospray ionization, IS: internal standard, MRM: multiple reaction monitoring.
authors.affiliation: Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, P.R. China; Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Province Academy of Chinese Medicine, Nanjing, Jiangsu, P.R. China.
authors.forename: Li
authors.initials: L
authors.lastname: Cui
authors.affiliation: Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, P.R. China; Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Province Academy of Chinese Medicine, Nanjing, Jiangsu, P.R. China.
authors.forename: E
authors.initials: E
authors.lastname: Sune
authors.affiliation: Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, P.R. China; Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Province Academy of Chinese Medicine, Nanjing, Jiangsu, P.R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Song
authors.affiliation: Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, P.R. China; Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Province Academy of Chinese Medicine, Nanjing, Jiangsu, P.R. China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, P.R. China; Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Province Academy of Chinese Medicine, Nanjing, Jiangsu, P.R. China.
authors.forename: Xiao-Bin
authors.initials: XB
authors.lastname: Jia
authors.affiliation: Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, P.R. China; Key Laboratory of New Drug Delivery System of Chinese Materia Medica, Jiangsu Province Academy of Chinese Medicine, Nanjing, Jiangsu, P.R. China.
authors.forename: Zhen-Hai
authors.initials: ZH
authors.lastname: Zhang
keywords: Baicalin; dissolution; mesoporous carbon nanopowder; oral bioavailability; solid dispersion