title: [Simultaneous determination of serum concentrations of amoxicillin and clavulanate potassium in human blood using high-performance liquid chromatography].
abstract: OBJECTIVE
  To establish a chromatography-based method for simultaneous analysis of the concentrations of amoxicillin and clavulanate potassium in human blood.
  
  
  METHODS
  With paracetamol as the internal control, human plasma samples, after treatment with methanol for protein sedimentation and centrifugation, were loaded for analysis with high-performance liquid chromatography (HPLC). HPLC analysis was carried out using a C18 column (5 µm, 4.6 mm×150 mm) with the mobile phase of acetonitrile-PBS (0.05 mol/L) of 10:90 (pH 2.3), UV detection wavelength of 220 nm, flow rate of 1.0 ml/min, and column temperature of 25 degrees celsius;.
  
  
  RESULTS
  The retention time of acetaminophen for potassium clavulanate, amoxicillin sodium and the internal control was 5.3, 7.2, and 8.5 min, respectively, and no interference by the endogenous impurities in the plasma samples was found. Amoxicillin sodium showed a good linearity within the concentration range of 0.52-4.16 µg/ml (r(2)=0.9996), and potassium clavulanate had a good linearity within the range of 0.266-2.14 µg/ml (r(2)=0.9998). The minimum detectable concentrations of amoxicillin sodium and potassium clavulanate were 0.065 µg/ml and 0.066 µg/ml, respectively. The relative recoveries of amoxicillin sodium were 95.9%-96.5% (n=5), and those of clavulanate potassium were 92.5%-98.8% (n=5); the intra- and inter-day RSD of amoxicillin sodium was 1.84%-6.4% and 2.1%-7.8%, as compared to that of potassium clavulanate of 3.57%-8.6% and 1.8%-9.1%, respectively.
  
  
  CONCLUSIONS
  This method is simple, accurate, sensitive, specific and reproducible for analyzing the concentrations of amoxicillin and clavulanate potassium simultaneously in human plasma.
authors.affiliation: Guangdong Academy of Medical Sciences, Guangdong General Hospital, Guangzhou 510080, China. lin_zuwen@163.com
authors.forename: Zu-wen
authors.initials: ZW
authors.lastname: Lin
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: Wei-juan
authors.initials: WJ
authors.lastname: Song
authors.forename: Hai-yan
authors.initials: HY
authors.lastname: Hu
authors.forename: Ying
authors.initials: Y
authors.lastname: Zeng
authors.forename: Bai-hong
authors.initials: BH
authors.lastname: Xu
mesh_terms: D000658:Amoxicillin / Q000097:blood*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019818:Clavulanic Acid / Q000097:blood*; D004355:Drug Stability; D006801:Humans
chemical_list: D019818:Clavulanic Acid; D000658:Amoxicillin