Validation of direct method to quantify dexamethasone in human aqueous humor by LC-MS/MS.

Aim: Dexamethasone (Dex) has been used for the treatment of ocular diseases, presenting concentrations up to 150 ng/ml in the biological matrix. Drug sampling has been performed from aqueous humor (AH), which the volume varies from 50 to 200 μl, becoming a challenge for analytical analyses.

Results: We developed and validated a direct and sensitive method by LC-MS/MS for Dex measurement in human AH, using water as surrogate matrix to reduce the sample volume applied in some validation assays.

High sensitivity method validated to quantify estradiol in human plasma by LC-MS/MS.

17β-Estradiol (E2) is an endogenous steroid in the human body. Its measurement is important for health and human biology understanding. However, E2 concentration in human plasma is in the range of pg/mL, which makes it difficult to detect.