Solid-Phase Extraction and HPLC-DAD for Determination of Salbutamol in Urine Samples

Validation of a solid-phase extraction and a high-performance liquid chromatographic assay for determination of Salbutamol in urine samples is described. HPLC-DAD method was established for determination of Salbutamol in urine samples following inhaled administration by 0.5 and 24 h after cleanup procedure. Agilent ODS 5 μm, 4.6×250 mm, C-18 stationary phase with a mobile phase consisting of a mixture of acetonitrile and water (adjusted to pH = 3 using orthophosphoric acid) (90: 10, v/v) at a flow rate 1 mLD min with detection at 220 nm and Bambuterol HCl as an internal standard were used for development of the method. Solid phase extraction was performed using Oasis MCX cartridge for both un-metabolized Salbutamol (excreted after 0.5 h) and metabolized Salbutamol (excreted after 24 h) with mean percentage recoveries of 92.24% and 91.52%, respectively. The method described permits the detection of Salbutamol in human urine at concentration as low as 0.15 μg/mL. The proposed method was successfully applied for determination of Salbutamol in urine samples after inhalation of a metered dose inhaler (MDI) of Ventolin® to healthy volunteer after 0.5 and 24 h. The proposed method can be used for pharmacokinetic study of Salbutamol and determination of its relative deposition in the lung.