Study of urinary 6β-hydroxycortisol/cortisol ratio in spot urine sample as a biomarker of 3A4 enzyme activity in healthy and epileptic subjects of Egyptian population

The ratio of urinary 6β-hydroxycortisol/cortisol (6β-OHC/FC) in morning spot urine samples collected from 8:00 a.m. to 12:00 p.m. was studied using ELIZA kits (Stabiligen) in a group of healthy adult Egyptians (control group) of both sex (n = 65, age range: 16-48 years). The frequency distribution of urinary 6β-OHC/FC ratio was widely distributed among subjects with higher values in males in comparison to females. No bimodality in either sex was observed. Another group of adult epileptic patients (n = 16) was studied for the influence of chronic carbamazepine antiepileptic drug administration on urinary 6β-OHC/FC ratio in spot urine samples. The induction property of carbamazepine on CYP3A4 was observed through significant increase (p = 0.01) in 6β-OHC/FC ratio among epileptic patients in comparison with control subjects. In conclusion, the frequency distribution of urinary 6β-OHC/FC ratio among Egyptians shows sexual dimorphism. Also, measurement of urinary 6β-OHC/FC ratio provides a simple non-invasive method to monitor CYP3A4 enzyme induction during administration of carbamazepine antiepileptic drug.