title: Preparation and Characterization of Silymarin Synchronized and Sustained Release Dropping Pill.
abstract: OBJECTIVE
  This study aimed to develop a synchronized and sustained-release silymarin dropping pill, and to evaluate its pharmacokinetic characteristics.
  
  
  METHODS
  Polyoxyethylene stearate, glyceryl monostearate, and stearic acid were used to prepare the dropping pills. X-ray powder diffraction, differential scanning calorimetry, and release were used to evaluate its physicochemical properties. The plasma concentration of silybin in beagle dogs after oral administration of silymarin dropping pills and silymarin capsule was determined by RP-HPLC.
  
  
  RESULTS
  Synchronized release was achieved with high similarity factor f2 values between every set of two of the five components. Mean plasma concentration-time curves of silymarin after oral administration of dropping pills in beagle dogs were in accordance with first-order absorption and open twocompartment model. The Tmax, Cmax, and AUC0-∞ of dropping pills in beagle dogs were 0.8750±0.13 h, 0.8183±0.07 μg·ml-1, and 2.274±0.90 μg·h·ml-1, respectively. Silymarin dropping pills prolonged in vivo exposure and reduced maximum in vivo concentration, achieving a stable level in the serum.
  
  
  CONCLUSIONS
  The combination of solid dispersion technique and dropping pill formulation allowed synchronized release of multiple components in herbal medicine, and has potential application in the development of sustained release in herbal medicine.
authors.affiliation: Department of Pharmacy, Fuzhou General Hospital of Nanjing Command PLA, Fuzhou 350025, China.
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Liu
authors.affiliation: Department of Pharmacy, Fuzhou General Hospital of Nanjing Command PLA, Fuzhou 350025, China.
authors.forename: Xue-Jing
authors.initials: XJ
authors.lastname: Li
authors.affiliation: Department of Pharmacy, Fuzhou General Hospital of Nanjing Command PLA, Fuzhou 350025, China.
authors.forename: Ai-Wen
authors.initials: AW
authors.lastname: Huang
authors.affiliation: Department of Pharmacy, Fuzhou General Hospital of Nanjing Command PLA, Fuzhou 350025, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Pharmacy, Fuzhou General Hospital of Nanjing Command PLA, Fuzhou 350025, China.
authors.forename: Hong-Tao
authors.initials: HT
authors.lastname: Song
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001682:Biological Availability; D003692:Delayed-Action Preparations; D004285:Dogs; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage* / Q000493:pharmacokinetics; D012838:Silymarin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D012995:Solubility
chemical_list: D003692:Delayed-Action Preparations; D004365:Drugs, Chinese Herbal; D012838:Silymarin
keywords: Bioavailability; dropping pills; silymarin; solid dispersion technique; sustained release; synchronized release