A METHOD FOR PRESERVING SALIVA SAMPLES AT AMBIENT-TEMPERATURES

To facilitate biochemical and biopharmaceutical studies when cold stor age is unavailable, we assessed the stability of saliva samples contai ning preservatives stored at room temperature over a 1-year period. Tw o preservative mixtures were evaluated: sodium benzoate and citric aci d (P1), and ethyl and propyl paraben (P2). Saliva samples were spiked with acetaminophen (APAP) or antipyrine (AP) and stored in preservativ e-coated vials and examined for concentrations of APAP, AP, melatonin, and cortisol at regular intervals as a function of preservative type and storage duration. Samples were stored at room temperature or at -2 0 degrees C (positive control) and analyzed periodically for APAP and AP by high-performance liquid chromatography and for melatonin and cor tisol by radioimmunoassay. The effectiveness of the preservatives was determined by calculating the value of samples stored at room temperat ure in terms of percent of control (-20 degrees C) values. P1 effectiv ely maintained the stability of APAP (100%) and AP (100%) for 360 days at room temperature; concentrations in samples at room temperature on day 360 were comparable to those on day 01. P1 also effectively maint ained melatonin (100%) and cortisol (95%) concentrations for 180 days at room temperature. P2 preserved AP and cortisol in saliva for 60 day s, but APAP for only 14 days.