A simple, rapid, accurate and precise spectrophotometric method is proposed for determining metoclopramide-hydrochloride (MCPH) in pure form and in pharmaceutical preparations .The method is based on oxidation-reduction reaction between metoclopramide-hydrochloride and cerium (IV) ion, then the subsequent reaction of cerium (III) and arsenazo III reagent in acidic medium to produce a blue-violet complex which is stable, water-soluble and has a maximum absorption at 654nm with a molar absorptivity of 9.36x10 4 l.mol-1 .cm-1 and Sandell's sensitivity of 0.0038 µg.cm-2. Beer's law is obeyed in concentration range from 1-30 µg metoclopramide-hydrochloride in final volume of 25 ml, (0.04-1.2) ppm with a relative standard deviation (RSD) (±1.80%-±3.98%) and the limit of detection (LOD) is 0.0095 µg/ml and the limit of quantitation (LOQ) is 0.0317 µg/ml. The method is suitable for the determination of metoclopramidehydrochloride in the presence of other ingredients that are usually present in dosage forms and the recoveries are obtained in the range of 97.6-101.0 %. The proposed method has been applied successfully to the determination of the intended compound in its pharmaceutical preparations (tablet and injection).

A New, sensitive spectrophotometric method for determination of Naproxen (Nap) has been proposed. The method is based on a modification of Naproxen into a hydroxy analog (mNap). The modified compound is coupled with the diazotized p-aminobenzoic acid (PABA) in alkaline medium, the resulting orange azo dye exhibit a maximum absorption at 500 nm. Beer's law is obeyed over the concentration range from 10 to 650 µg/20 ml, (i.e. 0.5-32.5 µg/ ml) with a good sensitivity (molar absorptivity 2.14x10 4 l.mol -1 .cm -1 ), good precision (RSD% better than ±1.93%) and high accuracy (relative error % better than 0.43%), Sandell's sensitivity index is 0.0107µg.cm -2 and the limit of detection (LOD) is 0.024 µg/ml and the limit of quantitation (LOQ) is 0.082 µg/ml. The method has been applied successfully for determination of Naproxen in dosage forms after extraction of the active ingredient.

A novel and secure indirect spectrophotometric technique for estimation of naproxen as a coupled compound with paracetamol as a unharmed diazotized reagent than organic reagents. Naproxen was first converted into an active form to act as coupling agent by reflux with hydrobromic acid (HBr) and acetic acid (CH3COOH) to yield the Hydroxy Form of Naproxen (HFN). The diazotized complex absorb light in wavelength 500 nm. Beer's law linearity is 10 to 200 µg/20ml, (i.e. 0.5-10.0 ppm), the molar absorptivity (ɛ) is 2.14x10 4 l/mol.cm, Sandell's sensitivity index (SSI) is 0.0094 µg/cm which indicate a high sensitivity, RSD more than ±0.36 % indicate good precision and higher accuracy (relative error more than 0.82 %), and LOD = 0.024 µg/ml and LOQ = 0.079 µg/ml. The technique has been used effectively for estimation of naproxen in tablets.