A simple, fast and sensitive spectrophotometric method has been applied for the determination of tetracycline hydrochloride in its pure form and in pharmaceutical preparations. The method based on coupling reaction of the antibiotic with diazotized anthranilic acid to form a stable yellow azo dye which shows a maximum absorption at 419 nm. Uni- and multivariate approaches were followed in optimizing the experimental conditions. Under optimum experimental conditions obtained via multivariate (Central Composite Design), the linearity of the constructed calibration curve was in the range of 0.560 μg.mL-1 with molar absorptivity of 14619 L.mol-1.cm-1 and the value of detection limit was 0.2813μg.mL-1. The capability of the metho

Determining the actual amounts of active ingredients in various pharmaceutical commercial forms is still receiving a lot of attention. Two flow injection analysis (FIA) methods were suggested for determination of mesalazine (MES) in pharmaceutical forms. Normal and reverse FIA systems (nFIA and rFIA) combined with UV-Vis spectrophotometric technique were used for the analysis. The methods involved using two mods of FIA systems for measuring a colored product result from coupling of MES with 2,2'-dihydroxybiphenyl after oxidized with sodium periodate in alkaline medium. The absorbance of the red colored dye was measured at maximum wavelength of 500 nm. The calibration graphs for MES were linear in the ranges 2.5-200 and 0.5-60 µg/mL with

Two methods have been applied for the spectrophotometric determination of atropine, in
bulk sample and in dosage form. The methods are accurate, simple, rapid, inexpensive and
sensitive. The first method depending on the extraction of the formed ion-pair complex with
bromphenol blue (BPB) as a chromogenic reagent in chloroform, use phthalate buffer of pH
3.0; which showed absorbance maxima at 413 nm against reagent blank. The calibration
graph is linear in the ranges of 0.5-40 µg.mL
-1
with detection limit of 0.363µg.mL
-1
. The
second method depending on the measure of the absorbance maxima of the formed charge-transfer complex with 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) at 457 nm against

A simple, and rapid spectrophotometric method for the estimation of paracetamol has been developed. The methods is based on diazotisation of 2,4-dichloroaniline followed by a coupling reaction with paracetamol in sodium hydroxide medium. All variables affecting the reaction conditions were carefully studied. Beer's law is obeyed in the concentration range of 4-350 ?gml?1 at 490 nm .The method is successfully employed for the determination of paracetamol in pharmaceutical preparations. No interferes observed in the proposed method. Analytical parameters such as accuracy and precision have been established for the method and evaluated statistically to assess the application of the method.

Amiodarone hydrochloride (AH) has been determined spectrophotometrically Using methyl orange (MO).  In our previous researches MO was used for determination of Mexiletine Hydrochloride [1]. The method based on complexation between MO and AH.  After shaking and diluting the complex solution with D.W, the pH was adjusted with NaOH and HCl to pH 3. The colored complex formed between AH and the reagent were transferred into separating funnels and extracted using 5.5ml CH2Cl2 and were shaken for (5 minutes).  The extracted organic layer was used for preparation of the calibration curves for spectrophotometric measurements of AH at 434nm.  The blanks were carried out in exactly the same way throughout the whole procedure.&n

Spectrophotometric  methods  were  developed   for    the determination of rantidine-HCl in pharmaceutical tablets. These methods were based on the reaction of DDQ and p-chloranil with rantidine-HCl, resulting in the formation of an orange-red and purple colored products which are quantified spectrophotometrically at 460 and 540nm in DDQ and p-chloranil, respectively. A graph of absorbance versus concentration show that Beer’s law is obeyed in a concentration ranges of 20-160 and (30-120)g/ml with molar absorptivities of 2.631 x 103 and 1.052 x 103l .mol-1-cm-1 for DDQ and  p-chloranil, respectively. The optimum conditions for  color development  are described and 

  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.
 

            A new, simple, rapid and sensitive spectrophotometric method for the determination of sulfamethoxazole in both pure form and pharmaceutical preparations has been reported.The adapted technique based on utilization 4-aminobenzene sulfonic acid as a new modern chromogenic through an oxidative coupling reaction with sulfamethoxazole and potassium iodate in basic media to form orange soluble dye product with absorption maxima at 490 nm. Subject to Beer's law in the range 2–32μg mL^-1. The values of molarabsorption coefficient (ε) and correlation coefficient were found to be 9.118 × 10³ and0.9999 respectively whereas the Sandels index was