Drug-protein binding in elderly subjects

Abstract

It is important to know the magnitude of serum-protein binding of drug dynamics in vivo. The authors investigated the effects of a variety of serum free fatty acids in elderly subjects. Serum albumin levels and ceftezole (CTZ)-protein binding in elderly subjects were lower than in younger subjects. No significant difference was noted between the two groups in regard to total free fatty acid (T-FFA) level. However, compared with younger subjects, palmitolic and oleic acid were higher and myristic and linoleic acid were lower in elderly subjects, suggesting that free fatty acid (FFA) undergoes qualitative changes due to ageing. In elderly subjects CTZ-binding correlated negatively with T-FFA, oleic acid and linoleic acid, but positively with stearic acid. Oleic acid decreased CTZ-protein binding. This decrease was higher than that due to decreased albumin levels in elderly subjects with albumin levels less than 4.0 g/dl. These findings indicated that reduced protein binding in elderly subjects is due to decreased serum albumin and changes in FFA constitution with ageing. Therefore it was suggested that drug-albumin binding may change due to the competitive action of albumin sites, and albumin-drug binding capacity. Since drug-protein binding capacity seriously affect metabolism, excretion, efficacy and side effects due to the presence of free drugs, these aspects require further investigation in elderly subjects.