title: A conventional HPLC-MS method for the simultaneous determination of ofloxacin and cefixime in plasma: Development and validation.
abstract: OBJECTIVE
  A simple, rapid, and sensitive high performance liquid chromatography-mass spectrometry (HPLC-MS) method was developed and validated for the simultaneous determination of ofloxacin (OFL) and cefixime (CEF) in human plasma using the moxifloxacin as internal standard.
  
  
  METHODS
  Analytes were separated using an Agilent LCMS system equipped with a Zorbax eclipse XBD C18 column (150 mm × 4.6 mm i.d., 5 μm) and using a mobile phase consisting of a mixture of acetonitrile, methanol and 0.5% formic acid in a ratio of 23:10:67% v/v and flow rate was set at 0.6 mL/min. Plasma samples were extracted using the protein precipitation with acetonitrile and analyzed by positive ion mode.
  
  
  RESULTS
  The linearity of the proposed method was investigated in the concentration range of 4-500 ng/mL (r = 0.9996) for OFL and 40-6000 ng/mL (r = 0.9998) for CEF. The lower limits of quantification were 4 ng/mL and 40 ng/mL for OFL and CEF respectively, which reach the level of both drugs possibly found in human plasma. Further, the reported method was validated as per the ICH guidelines and found to be well within the acceptable range.
  
  
  CONCLUSIONS
  The proposed method is simple, rapid, accurate, precise, and appropriate for pharmacokinetic and therapeutic drug monitoring in the clinical laboratories.
authors.affiliation: Department of Pharmaceutical Science, College of Clinical Pharmacy, King Faisal University, Al-Ahsa 31982, Saudi Arabia.
authors.forename: Mahesh V
authors.initials: MV
authors.lastname: Attimarad
authors.affiliation: Department of Chemistry, College of Science, King Faisal University, P. O. Box 400, Al-Ahsa 31982, Saudi Arabia.
authors.forename: Ahmed O
authors.initials: AO
authors.lastname: Alnajjar
keywords: Cefixime; HPLC-MS; ofloxacin; plasma; validation