title: LC-MS/MS assay for quantitation of enalapril and enalaprilat in plasma for bioequivalence study in Indian subjects.
abstract: BACKGROUND
  Enalapril (EPL) is an angiotensin-converting enzyme inhibitor for the treatment of hypertension and chronic heart failure. Enalaprilat (EPLT) is an active metabolite that contributes to the overall activity of EPL.
  
  
  OBJECTIVE
  To quantitate EPL along with its metabolite EPLT using LC-MS/MS, a bioanalytical method was developed and validated with tolbutamide in human plasma using a protein precipitation technique.
  
  
  RESULTS
  The sensitive and selective method has an LLOQ of 1 ng/ml with a linearity range of 1-500 ng/ml for both EPL and EPLT using 300 µl of plasma without any matrix effect.
  
  
  CONCLUSIONS
  Linearity, specificity, accuracy, precision and stability, as well as its application to the analysis of plasma samples after oral administration of 20 mg of EPL maleate in healthy volunteers demonstrate applicability to bioavailability/bioequivalence studies.
authors.affiliation: Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India; Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
authors.forename: Dhiman
authors.initials: D
authors.lastname: Halder
authors.affiliation: Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India; Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
authors.forename: Shubhasis
authors.initials: S
authors.lastname: Dan
authors.affiliation: TAAB Biostudy Services, Kolkata 700032, India; TAAB Biostudy Services, Kolkata 700032, India.
authors.forename: Murari Mohun
authors.initials: MM
authors.lastname: Pal
authors.affiliation: Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India; Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
authors.forename: Easha
authors.initials: E
authors.lastname: Biswas
authors.affiliation: TAAB Biostudy Services, Kolkata 700032, India; TAAB Biostudy Services, Kolkata 700032, India.
authors.forename: Nilendra
authors.initials: N
authors.lastname: Chatterjee
authors.affiliation: Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India; Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
authors.forename: Pradipta
authors.initials: P
authors.lastname: Sarkar
authors.affiliation: Organic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata, India; Organic Chemistry Section, Department of Chemistry, Jadavpur University, Kolkata, India.
authors.forename: Umesh Chandra
authors.initials: UC
authors.lastname: Halder
authors.affiliation: Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India; Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University, Kolkata, India.
authors.forename: Tapan Kumar
authors.initials: TK
authors.lastname: Pal
keywords: LC–MS/MS; bioequivalence study enalapril; enalaprilat; human plasma; protein precipitation