title: Validated LC coupled to ESI-MS/MS analysis for fentanyl in human plasma and UV analysis in applied reservoir transdermal patches using a simple and rapid procedure.
abstract: OBJECTIVE
  Fentanyl has been used for cancer pain in transdermal formulation. The aim of the present study was to establish an analytical method for fentanyl in human plasma and in an applied transdermal reservoir patch (Reservoir-TTS), as well as for therapeutic monitoring of fentanyl in cancer patients.
  
  
  METHODS
  Electro-spray ionization mass spectrometric (ESI-MS/MS) analysis followed solid phase extraction (SPE) from human plasma and drug reservoir extraction from an applied Reservoir-TTS. Each separation was completed within 9 min using an ODS column (particle size, 3 microm, 2.0 mm i.d. x 75 mm) with 25% acetonitrile containing 5 mm ammonium acetate at pH 3.5. In the ESI-MS/MS analysis, the calibration curve for fentanyl was linear over a concentration range of 0.05-7.2 ng/mL in human plasma. The extraction efficiency of fentanyl in the human plasma was more than 95%. The intra- and interassay precision and accuracy were within 7% and 97.3-101.2%, respectively. The lower LOQ for fentanyl was 0.05 ng/mL in the human plasma. The extraction of the 25 microg/h and 50 microg/h Reservoir-TTS gave reproducible recoveries of 88.3% and 90.9%, respectively. The plasma concentration of fentanyl showed large interindividual variation in 31 patients with cancer pain.
  
  
  CONCLUSIONS
  The method described is simple, accurate, and reproducible, and should be helpful for the therapeutic monitoring of fentanyl in cancer patients.
authors.affiliation: Department of Hospital Pharmacy, Hamamatsu University School of Medicine, Higashi-ku, Hamamatsu, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takashina
authors.forename: T
authors.initials: T
authors.lastname: Naito
authors.forename: Y
authors.initials: Y
authors.lastname: Mino
authors.forename: Y
authors.initials: Y
authors.lastname: Kagawa
authors.forename: J
authors.initials: J
authors.lastname: Kawakami
mesh_terms: D000279:Administration, Cutaneous; D002138:Calibration; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D005283:Fentanyl / Q000032:analysis* / Q000097:blood / Q000737:chemistry; D006801:Humans; D009369:Neoplasms / Q000503:physiopathology; D010148:Intractable Pain / Q000188:drug therapy; D015203:Reproducibility of Results; D052616:Solid Phase Extraction; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013056:Spectrophotometry, Ultraviolet
chemical_list: D005283:Fentanyl