A rapid, simple, and sensitive spectrophotometric and high performance liquid chromatographic methods have been developed for the quantitative determination of metoclopramide hydrochloride (MCP) in both pure and dosage forms. The spectrophotometric method is based on diazotization of (MCP) and then coupling with 2,4dihydroxyacetophenone in alkaline medium. The resulting azodye exhibits maximum absorption at 450 nm with a molar absorptivity of 2.48 X 10 4 l.mol-1 .cm-1. Beer's law is obeyed over the range 10-300µg/25 ml, i.e., 0.4-12 ppm with a relative standard deviation (RSD)of better than±1.092% and relative error better than-1.1%. HPLC method has been developed for the measurement of (MCP), the analysis was achieved on a C 8 column using acetonitrile, water, and methanol in the ratio of 40:50:10 (V:V:V) (in the presence of 1% of sodium acetate) as a mobile phase by isocratic elution at 1 ml/min. flow rate, and detection was done spectrophotometrically at 308 nm. A linear relationship is obeyed over the range 0.18-0.8 ppm with a relative standard deviation (RSD) of better than ±3.7% and relative error better than-1.6%. Both methods were applied successfully to the assay of (MCP) in pharmaceutical preparations in the form of syrup, injection, and tablet.

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.

Loperamide hydrochloride (LopH) has been determined by oxidative -coupling reaction using phenothiazine reagent in the presence of potassium dichromate as an oxidant to create a greenish-blue soluble complex measured at 625 nm., linearity range is from0.8 to 40 µg.ml -1 of LopH. The molar absorptivity is 0.3799×10 4 l.mol -1 .cm -1 , Sandell's sensitivity is 0.1351µg cm -2, limit of detection and limit of quantitation are 0.33918, and 1.1306 µg.ml -1 respectively. The method is new ,simple, sensitive and it has been applied successfully for determination of LopH in pharmaceutical preparation of three dosage forms of LopH; Loperamide 2 mg/tablets Medochemie Ltd, Limassol-Cyprus (Europe), Loperamide 2 mg/tablets Safa Co. -Diala (Iraq) and Loperamide 2 mg/capsules Janssen pharmaceuticals (Belgium).

Determination of vitamin B6 (pyridoxine hydrochloride) was described using high performance liquid chromatographic method. The analysis was achieved by cosmos IL 5C18-MS-II column (250 mm x 4.6 mm i. d., 5µm particle size) at room temperature. The mobile phase used was Acetonitrile, buffer solution (Citric acid, Na2HPO4 pH4) buffer solution in the ratio (70:30) (V: V). the flow rate was set to 1.25 mL.min-1 and the retention time 1.82 min with UV-detection at 282 nm. Beer's law was obeyed over the concentration range 10-1250 µg.mL-1. The method was accurate (relative error % less than 0.05%), precise (RSD better than ±1.05%), average recovery 100.05%, with a limit of detection and quantification of 2.2μg.ml−1, and 7.34μg.mL−1 respectively. The proposed method was successfully applied to determine the pyridoxine hydrochloride in pharmaceutical preparations in both forms of tablet and injection

A simple, precise, and friendly environmental method for the determination of paracetamol and tramadol hydrochloride in pharmaceutical preparations has been worked out. The method is based on the determination of paracetamol at 242 nm and replaces its concentration in a multicomponent system equation for determination of both paracetamol and tramadol at 227 nm. Beer's law for paracetamol was obeyed over the concentration range 8-25 ppm at 242 nm and 4-16 ppm at 227 nm ,for tramadol it is obeyed over the range 2-14 ppm at 227 nm, water is used as a solvent for dissolution. The method is applicable to the determination of paracetamol and tramadol in their pharmaceutical preparations without prior separation steps from excipients as well as for determination of paracetamol in the presence of tramadol. The average recoveries for determination of mentioned drugs were 94.20-100.14%, and the average relative standard deviation of the method was better than ± 0.646%.