No abstract

A simple, accurate and sensitive method for determination of bromhexine hydrochloride drug in aqueous solution has been described. The procedure has been based on the reaction of this drug with an excess amount of p-dimethylaminobenzaldehyde (DAB) in acidic medium (pH = 1.6) and the presence of sodium dodecyl sulfate (SDS). The produced yellow color from this reaction has been followed spectrophotometrically at an absorbance maximum of 430 nm. Microgram amounts of bromhexine hydrochloride can be estimated with an accuracy of better than ±1.5% and a relative standard deviation of less than 3.5%. The method has been used for the determination of 0.41-82.5 mg.mL -1 with a molar extinction coefficient of 4699.1-3602.3 L.mol -1 .cm -1 . An application of the developed procedure to bulk bromhexine hydrochloride and some of its pharmaceutical preparations has been carried out. The effect of the presence of some other surfactants and common pharmaceutical additives has been investigated. A comparison of the presented method with that in the absence of SDS and the standard method of the British Pharmacopoeia has been explored. The suggestion, according to the results, is to use the developed method as standard in pharmaceutical applications.

A simple, sensitive and green spectrophotometric method for the determination of metoclopramide hydrochloride (MTC) was developed. The method was based on the reaction of MTC with p-dimethylaminobenzaldehyde (DAB) in acidic aqueous medium (pH 2) in the presence of anionic surfactant sodium dodecyl sulfate (SDS) to give a yellow colored Schiff's base with a maximum absorbance at 452 nm. Obedience to Beer's law is achieved in the concentration range 0.2-18.0 µg mL -1 (5.6×10 -7 -5.1×10 -5 mol L -1 ), with relative error about 1%, relative standard deviation of less than 0.8% and molar absorptivity 3.02×10 4 L mol -1 cm -1 . The effect of the presence of some common pharmaceutical additives was investigated. The developed procedure was successfully applied to the determination of the drug in pharmaceutical formulations.

An accurate, cost-effective and simple method has been described for the quantitative determination of Tetracycline hydrochloride (TCs) in bulk and pharmaceutical samples using an aqueous medium. The proposed method is based on the nucleophilic substitution reaction of 9-chloroacridine (9-CA) as a chromogenic reagent with TCs in an aqueous solution forming a colored complex. The spectrum of the product shows maximum absorption at 385 nm against the blank. The linearity range of the calibration graph was (1-28) μg.mL -1 with a limited detection value (LOD) 0.138 μg.mL -1 . The results show the absence of interferences from the excipients compounds on the determination of the drug. The suggested method exhibited high reproducibility (RSD) 2.3 % with mean percentage recovery (R%) 99.95. Furthermore, the stability constant has been calculated to be 9.843×10 5 L.mol -1 and the reaction mechanism is proposed. A ratio of 1: 1 was found between the above drug and the reagent using Job and molar ratio methods. The accuracy and validity of the proposed method were further determined by performing a recovery experiment by the use of the standard addition method. It is found that the method does not require extraction process and it agree well standard addition method. Application of the suggested method to commercial pharmaceutical preparations (capsule and ointment) is presented.

A simple and accurate spectrophotometric method has been suggested for the determination of Mesalazine (MES), carbamazepine (CAM) and diclofenac sodium (DFS) in pure and pharmaceutical dosages. The method is based on the oxidation of drugs in acidic medium with known excess of N-bromosuccinimide (in case of MES), or bromate-bromide mixture (in case of CAM and DCF) and subsequent determination of unreacted oxidant by decolorization of nile blue dye (NB) and measure the absorbance of unoxidized dye at 640 nm. Calibration curves of the dye in the presence of studied drugs were rectilinear over the ranges 0.1-2.2, 0.4-2.4 and 0.6-2.8 µg ml-1 with molar absorptivity of 6.21×10 4 , 1.05×10 5 and 1.21×10 5 l.mol-1 .cm-1 for MES, CAM and DCF respectively. The common excipients and additives didn't interfere in their determination. The suggested method was successfully applied for determination of the studied drugs in their pharmaceutical forms resulted in a good agreement with standard British pharmacopeia method and standard addition procedure.