Stability - indicating methods for the determination of lorazepam, delorazepam and tetrazepam

Two simple, rapid and accurate techniques have been developed for the determination of lorazepam, delorazepam and tetrazepam in the presence of their degradation products. The first one depends on the derivative ratio spectrophotometry while the second depends on spectrodensitometry. The validity of the proposed procedures was proved using standard addition technique and laboratory-prepared mixtures of the drugs and their degradation products. The proposed procedures were successfully applied for the drugs analysis in their tablet dosage form

Three different techniques for the analysis of chlordesmethyldiazepam

Three simple, rapid and accurate different techniques have been developed for the determination of chlordesmethyldiazepam. The first one depends on the spectrophotometric determination of the orange azodye resulting from the coupling of thymol with the acid-induced hydrolysis product of chlordesmethyldiazepam after conversion to the corresponding diazonium salt in alkaline medium. The second is the application of quantitative densitometry for the determination of chlordesmethyldiazepam in the presence of its degradation benzophenone product. While, the third technique implies HPLC resolution efficiency in the determination of chlordesmethyldiazepam in the determination of chlordesmethyldiazepam in the presence of its degradation benzophenone product

Stability indicating methods for the determination of bromazepam

Three simple, accurate and stability indicating methods were developed for the determination of bromazepam in the presence of its degradation product. The first method depends on measuring the peak height of the first derivative difference absorbance after complete acid hydrolysis at 420 nm. The second method utilizes densitometry after separation on precoated TLC plates, while the third implies HPLC using RP 18 column, acetonitrile/water [40:60] as a mobile phase and diode array detector

Spectrophotometric determination of midazolam using 2,3-dichloro-5,6-dicyano-P-benzoquinone

In the present work, substituted quinines such as 2,3-dichloro-5,6- dicyano-p-benzoquinone [DDQ] is utilized in spectrophotometric determination of midazolam through the formation of orange-red colored charge transfer complex. The color is characterized by a maximum absorbance at 462.5 nm. Different reaction parameters were investigated. The proposed procedure was successfully applied for the determination of midazolam in bulk powder over a concentration range of 66-330 mug ml-1 and in different pharmaceutical preparations