Three sensitive, selective and reproducible stability-indicating methods are presented for determination of nitazoxanide (NTZ), a new anti-protozoal drug, in presence of its degradation products. Method A utilizes the first derivative of ratio spectra spectrophotometry by measurement of the amplitude at 364.4 nm using one of the degradation products as a divisor. Method B is a chemometric-assisted spectrophotometry, where principal component regression (PCR) and partial least squares (PLS) were applied. These two approaches were successfully applied to quantify NTZ in presence of degradation products using the information included in the absorption spectra in the range 260-360 nm. Method C is based on the separation of NTZ from its degradation products followed by densitometric measurement of the bands at 254 nm. The separation was carried out on silica gel 60F254, using chloroform-methanol-ammonia solution-glacial acetic acid (95:5:1:1 by volume, pH=5.80) as a developing system. These methods are suitable as stability-indicating methods for the determination of NTZ in presence of its degradation products either in bulk powder or in pharmaceutical formulations. Statistical analysis of the results has been carried out revealing high accuracy and good precision.

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.