Determination of Cortisol Levels in a Small Volume of Saliva of COVID-19-Recovering Patients During Treatment with Psychotropic Drugs.

: Cortisol levels are increased in stressful situations but can also result from a history of COVID-19 infection. Long-term exposure to high cortisol levels has a destructive effect on the CNS (Central Nervous System) and can lead to depression, among other things. The most commonly used psychotropic drugs reduce cortisol concentrations. The aim of our study was to develop an analytical method to determine the level of the hormone in a small volume of saliva (200 µL) in COVID-19 patients using CNS-active drugs. Solid-phase extraction was used to isolate the analyte, and the determination was performed by liquid chromatography with a diode array detector (LC with DAD). : The developed method was validated. Its linearity was determined to be in the range of 4-500 ng/mL (R > 0.9986) and the intra- and inter-day precision expressed as coefficient of variation (CV%) did not exceed 12%. The method was then applied to determine cortisol levels in the saliva of post-COVID-19-recovered patients and healthy volunteers. The determined cortisol levels were 12.24 ± 7.33 ng/mL in the recovered patients and 4.11 ± 1.46 ng/mL in the healthy subjects, respectively. A comparison of the results showed that cortisol levels in the recovered patients and healthy volunteers were significantly different statistically. : The developed method allowed for the determination of cortisol in a small volume of saliva. Comparison of cortisol concentration in healthy individuals and COVID-19 recoveries indicates that the hormone level in both groups significantly differed statistically, and the psychotropic drugs used did not reduce cortisol concentration in COVID-19 patients. The results obtained indicate that the psychotropic drugs used did not reduce cortisol concentrations in COVID-19 patients.