A batch and flow injection (FI) methods with spectrophotometric detection is proposed for determining of two of phenolic drugs: salbutamol sulphate(SLB)and pyridoxine hydrochloride(PYD) in pure and in pharmaceutical formulations. The methods utilized an oxidative-coupling reaction based upon oxidation of 2,4-dinitrophenylhydrazine (DNPH) with sodium periodate, where an electrophilic intermediate (diazonium salt of the reagent) is produced, which couples with either SLB or PYD in the presence of sodium hydroxide yielding a highly colored condensation product. The absorbance is measured after 15min at 525and515 nm for SLB and PYD respectively. Calibration graphs for both batch and FIA methods were linear over the concentration ranges of 1-24μg/ml for SLB and 0.4-16μg/ml for PYD, and of 30-1100μg/ml for SLB and20-1200μg/ml for PYD respectively. A detection limits of 0.580μg/ml SLB and 0.150μg/ml PYD for batch method, and 15.32μg/ml SLB and12.21μg/ml PYD for FIA method. The proposed methods were applied successfully to the determination of SLB and PYD in pharmaceutical preparations and were compared statistically with reference methods by means of t- test and F- test and were found not to differ significantly at 95% confidence level. The procedures are characterized by its simplicity, accuracy and precision. The results obtained were in good agreement with those obtained using reference methods for comparison.
A new spectrophotometric method for the determination of allopurinol drug was investigated. The proposed method was based on the reaction of the intended drug with catechol and Fe(II) to form a blue soluble complex which was measured at λmax 580 nm. A graph of absorbance versus concentration shown that Beer’s law was obeyed over the concentration range of 2–10 μg ml–1 with molar absorptivity of 9.4 x 103 l mol–1 cm–1 and Sandell sensitivity of 1.4 x 10–2 μg cm–2. A recovery percentage of 100% with RSD of 1.0%–1.3% was obtained. The proposed method was applied successfully for the determination of allopurinol drug in tablets with a good accuracy and
a simple accurate and sensitive spectrophotometric method for the determination of promethazine HCI has been developed the method is based on the oxidative coupling reaction of promethazine
A rapid and sensitive method for the determination of amoxicillin trihydrate (AMXT) based on the diazo-coupling reaction was studied. Sulphanilic acid diazotizes with nitrite ion in acidic medium to produce a water soluble, colorless diazonium ion, which subsequently coupled with AMXT to form a colored azo dye in the alkaline medium, having maximum absorption at 455 nm. The calibration graph showed that Beer's law is obeyed over the concentration range of 0.3 – 30.0 μg/mL of AMXT, with the detection limit of 0.15 μg/mL and molar absorptivity was 2.3 × 104 L/mol.cm. The accuracy and the precision were acceptable depending upon the values of error percentage and relative standard deviation. The influence of common interfer
... Show MoreThis paper concerned with development of a spectrophotometric method for the determination of paracetamol, based on the diazotisation and coupling reaction with anthranilic acid in basic medium, to form an intense yellow coloured, water-soluble and stable azo-dye which shows a maximum absorption at 421nm. Beer’s law is obeyed over the concentration range of 1.0-10 µg/ml; with molar absorptivity of 2.1772×104 L.mol -1.cm-1 and Sandell’s sensitivity index 6.9446 µg.cm-2. The method has been applied successfully for the determination of paracetamol in pharmaceutical formulation.
A new simple and sensitive spectrophotometric method for the determination of trace amount of Co(II) in the ethanol absolute solution have been developed. The method is based on the reaction of Co(II) with ethyl cyano(2-methyl carboxylate phenyl azo acetate) (ECA) in acid medium of hydrochloric acid (0.1 M) givining maximum absorbance at ((λmax = 656 nm). Beer's law is obeyed over the concentration range (5-60) (μg / ml) with molar absorptivity of (1.5263 × 103 L mol-1 cm-1) and correlation coefficient (0.9995). The precision (RSD% ˂ 1%). The stoichiometry of complex was confirmed by Job's method which indicated the ratio of metal to reagent is (2:1). The studied effect of interference elements Zn(II), Cu(II), Na(I), K(I), Ca(II) and Mg
... Show More
An accurate and sensitive spectrophotometric method has been developed for the determination of cefotaxime (CEF) in pure and pharmaceutical samples. The suggested method depended on the coupling reaction between diazotized cefotaxime and 3,5-dimethyl phenol (3,5-DMPH) in basic medium to form light orange, water soluble dye, that is stable and has a maximum absorbance at 497nm. The calibration graph was liner over the concentration range (1-70) µg.mL-1 with LOD of 0.750 µg.mL-1 and LOQ of. 2.740 µg. mL-1, sandal sensitivity of 0.0526 µg. cm-2 . molar absorptivity 11328 Lmol-1 cm-1 . The stoichiometry composition was found by Jobs a
... Show More A simple, accurate and precise spectrophotometric method has been proposed for the determination of Mefenamic acid(MA) in dosage forms. Proposed method based on the reaction of cited drug with 1,2-Naphthoquinone-4-Sulfonic sodium (NQS). The optimum experimental condition have been studied. Beer's Law is obeyed in the concentration range 0.5-10.0 µg/mL at 450nm with detection limit of 0.189µg/mL. Effect of pH, reaction time, and volume of NQS on the determination of Mefenamic acid, have been examined. The proposed method has been successfully applied for the determination of Mefenamic acid in pharmaceutical preparations.