Determination of Diazepam and associated compounds in pharmaceutical preparations

Permeability assessment of poorly water‐soluble compounds under solubilizing conditions: The reciprocal permeability approach

“…The solubility of DIA (p K a 3.3)25 in pH 7.4 KBR was 171.2 ± 0.4 µM (mean ± SD, n = 3). Solubility data for DIA in the presence of varying concentrations of PS‐80 was subsequently generated and used to determine the CMC of PS‐80, which was found to be 0.006% w/v.…”

Presence of synthetic pharmaceuticals as adulterants in slimming phytotherapeutic formulations and their analytical determination

“…Some advantages of CE, such as high-resolution power, short analysis time, and low consumption of chemicals and samples, make it an attractive method for this kind of investigation [36,38,39]. The most frequently used CE methods for the determination of adulterants are capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC) [19,[40][41][42][43][44][45][46][47]49]. A recent work published by de Carvalho et al [47] showed the possibility of using the CE with contactless conductivity detection (CE-C 4 D) as a screening method for eight adulterants (amfepramone, fenproporex, sibutramine, fluoxetine, bupropion, sertaline, paroxetine and flurazepam) in different phytotherapeutic formulations.…”

“…Table 2 summarizes the CE methods described in the literature for the determination of adulterants and includes their main analytical features. The summarized CE methods were developed for the screening and confirmation of the adulterants based on their migration times after the selective electrophoretic separation, followed by the quantification of the pharmaceuticals by using the addition of high purity reference standards [16,32,[44][45][46][47]49]. The use of CE-MS as a confirmation method for adulterants has not yet been described in the literature.…”

“…Solvent mixtures like water/methanol [3,41], water/ethanol [16,49], and methanol/THF [45] were also described in the literature for the adulterant analysis by CE methods. Here, the samples have to be sonicated for a defined period of time (10-60 min) and filtered through a 0.45 mm membrane prior to the injection in the electrophoretic systems.…”

Square-wave voltammetric techniques for determination of psychoactive 1,4-benzodiazepine drugs

“…Also, essential because of the presence of the phenyl rings, benzodiazepines have surface activity and are readily adsorbed on mercury. It is, therefore, not surprising that among other methods that have been used to determine benzodiazepines -immunoassay, chromatographic, and spectrophotometric [2,3,4,5,6,7,8] -electrochemical techniques using a mercury electrode seem to be efficient tools not only for solution studies but also for quantitative determination; these methods are also less time consuming [9]. In some studies the oxidative behaviour of those compounds at solid glassy carbon electrodes has been investigated [10,11] but less attention has been paid to studies of the electrochemical oxidation of the benzodiazepines.…”