Adult age and ex vivo protein binding of lorazepam, oxazepam and temazepam in healthy subjects

Abstract

Aim: To see if adult age correlates with ex vivo protein binding of lorazepam, oxazepam and temazepam in healthy subjects.

Methods: Sixty healthy drug free subjects were recruited in the age groups 18-39, 40-64 and ≥65 years. Plasma albumin concentrations were determined. Ex vivo unbound fractions (f(u)) were assessed by spiking samples and measuring the free and total concentrations.

Results: No correlation of age with f(u) was seen. The study was powered to demonstrate a change in f(u) of ≥7-10%. A decline in plasma albumin concentration of ~0.03 g l(-1) year(-1) was seen with increasing age (P= 0.032) and was associated with increased f(u) of lorazepam (P= 0.009) and oxazepam (P= 0.014).

Conclusions: There was no association of adult age with ex vivo f(u) of lorazepam, oxazepam or temazepam in healthy subjects.