title: Human saliva cortisone and cortisol simultaneous analysis using reverse phase HPLC technique.
abstract: BACKGROUND
  Hyper-hypo tension (like Cushing's syndrome, apparent mineralocorticoid excess syndrome and Addison's disease) diagnostic laboratory requires cortisol (F) analysis. The simultaneous analysis of human saliva F and cortisone (E), the inactive F metabolite, by solid phase extraction and RP-HPLC was studied.
  
  
  METHODS
  Saliva/standard samples were C18-SPE extracted, dried and resuspended. E and F were analysed by isocratic RP-HPLC (acetonitrile/water 27/73%) and UV detection. In the morning and in the evening Salivette stimulated saliva specimens were collected from healthy volunteers.
  
  
  RESULTS
  The E and F calibration curve ranges were 11.0-110.0 and 5.5-55.0 nmol/l respectively. The LOD was 0.2 and 0.1 nmol/l for E and F respectively. The intra and inter assay CVs were respectively 2.7-6.6 and 5.6-7.0% for E and 5.8-7.0 and 11.7-13.1% for F. The E and F spiked saliva sample recovery was 99% and 88% respectively. Saliva specimen stability was validated. E and F saliva levels in healthy volunteers were significantly (p<0.001) higher at 8 a.m. compared with 11 p.m. (26.4+/-8.9 vs. 4.3+/-2.9 nmol/l for E; 11.1+/-4.0 vs. 2.5+/-1.5 nmol/l for F, respectively).
  
  
  CONCLUSIONS
  This method is suitable for periodic analyses in a clinical biochemistry laboratory for endocrinology investigation purposes, simultaneously analysing E and F levels in a saliva specimen.
authors.affiliation: Section of Clinical Biochemistry, Department of Medical Diagnostic Sciences and Special Therapies, University of Padua, 35100 Padua, Italy. eliof.depalo@unipd.it
authors.forename: Elio F
authors.initials: EF
authors.lastname: De Palo
authors.forename: Giorgia
authors.initials: G
authors.lastname: Antonelli
authors.forename: Arianna
authors.initials: A
authors.lastname: Benetazzo
authors.forename: Maddalena
authors.initials: M
authors.lastname: Prearo
authors.forename: Rosalba
authors.initials: R
authors.lastname: Gatti
mesh_terms: D000328:Adult; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003348:Cortisone / Q000032:analysis*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000032:analysis*; D057927:Hydrophobic and Hydrophilic Interactions; D007201:Indicator Dilution Techniques; D008297:Male; D012463:Saliva / Q000737:chemistry*; D052616:Solid Phase Extraction
chemical_list: D003348:Cortisone; D006854:Hydrocortisone