Liquid chromatography–tandem mass spectrometric method for determination of salivary 17α-hydroxyprogesterone: A noninvasive tool for evaluating efficacy of hormone replacement therapy in congenital adrenal hyperplasia

A sensitive liquid chromatography–electrospray ionization-tandem mass spectrometric (LC–ESI-MS–MS) method for the quantification of 17α-hydroxyprogesterone (17OHP) in human saliva has been developed and validated. The saliva was deproteinized with acetonitrile, purified using a Strata-X cartridge, derivatized with a highly proton-affinitive reagent, 2-hydrazinopyridine, and subjected to LC–MS–MS. Quantification was based on the selected reaction monitoring, and deuterated 17OHP was used as the internal standard. This method allowed the reproducible and accurate quantification of the salivary 17OHP using a 200-μl sample, and the limit of quantitation was 5.0 pg/ml. The developed method was applied to clinical studies. A linear relationship was found to be positive (r2 = 0.975) between the blood 17OHP level and the salivary 17OHP level measured using the proposed method. The result from the salivary 17OHP measurement in patients with congenital adrenal hyperplasia demonstrated that the proposed method is very useful for monitoring of the therapeutic efficacy during hormone replacement therapy.