Determination of Dexamethasone Sodium Phosphate in Medicament by Fluorescence Probe of Tb³⁺-Tiron Complex

Abstract

A sensitive method by fluorescence quenching for the determination of dexamethasone sodium phosphate is proposed. The method is based on the ability of phosphate to inhibit the formation of a strong fluorescent complex of Tb³⁺ with tiron. The fluorescence intensity trends equilibrium after a 20-minutes reaction of dexamethasone sodium phosphate and Tb³⁺-tiron complex. The optimal conditions for the determination of dexamethasone sodium phosphate are studied. Under optimal conditions, the linear range is 2.5 × 10⁻⁷–4 × 10⁻⁶ mol/L and the detection limit is 6.2 × 10⁻⁸ mol/L, and the relative size distribution (RSD) of 11 times determination are 2.2% and 0.8% for 5 × 10⁻⁷ mol/L and 1 × 10⁻⁶ mol/L, respectively. The developed method is successfully applied to assay the dexamethasone sodium phosphate content in pharmaceutical injections.

Keywords:

• Dexamethasone sodium phosphate
• fluorescence quenching
• medicament
• Tb³⁺-tiron complex

Notes

^aExpressed in mg per ml.