title: Formulation and characterization of bufadienolides-loaded nanostructured lipid carriers.
abstract: OBJECTIVE
  The aim of this study was to design bufadienolides-loaded nanostructured lipid carriers (BU-NLCs) to reduce the degradation of drugs in rat plasma.
  
  
  METHODS
  BU-NLCs were prepared by a modified melt-emulsification ultrasonic technique and then characterized by particle size distribution, zeta potential, entrapment efficiency, differential scanning calorimetry, and X-ray diffraction.
  
  
  RESULTS
  The optimal formulation consisted of glyceryl monostearate 1.8%, medium-chain triglyceride 0.75%, oleic acid 0.45%, Lipoid E-80 1.5%, Pluronic F68 1.0%, and sodium deoxycholate 0.25%. The particle size distribution and the range of zeta potential of BU-NLCs were 104.1 +/- 51.2 nm and -15 to -20 mV, respectively. The entrapment efficiencies of the bufadienolides were all above 85%. In the enzymolysis study, the chemical stability of cinobufagin (C) in BU-NLCs was enhanced by being encapsulated in particles of NLC and adjusting the pH of the surrounding environment to 7.0. The half-life of C was 17-fold longer than that in bufadienolides solution. The in vitro release showed that the release from BU-NLCs was slower than from bufadienolides solution and followed the Weibull equation. Differential scanning calorimetry and X-ray diffraction showed that BU-NLC was in an amorphous state after lyophilization.
  
  
  CONCLUSIONS
  These results indicated that NLC could be developed as a carrier with improved drug plasma stability and offering controlled drug release.
authors.affiliation: Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, PR China.
authors.forename: Fang
authors.initials: F
authors.lastname: Li
authors.forename: Yanjiao
authors.initials: Y
authors.lastname: Wang
authors.forename: Zitong
authors.initials: Z
authors.lastname: Liu
authors.forename: Xia
authors.initials: X
authors.lastname: Lin
authors.forename: Haibing
authors.initials: H
authors.lastname: He
authors.forename: Xing
authors.initials: X
authors.lastname: Tang
mesh_terms: D000664:Amphibian Venoms; D000818:Animals; D002018:Bufanolides / Q000737:chemistry* / Q000493:pharmacokinetics; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004337:Drug Carriers / Q000737:chemistry* / Q000493:pharmacokinetics; D006801:Humans; D008055:Lipids; D049329:Nanostructures / Q000737:chemistry*; D051381:Rats; D014961:X-Ray Diffraction
chemical_list: D000664:Amphibian Venoms; D002018:Bufanolides; D004337:Drug Carriers; D008055:Lipids