Spectrophotometric method for the simultaneous determination of piroxicam and 2-aminopyridine

737-740A rapid and simple spectrophotometric method is proposed for the simultaneous determination of piroxicam (Pi) and 2-aminopyridine (2-Ap). Piroxicam is stable under basic hydrolysis, but yields 2-Ap as one of the degradation products under acid hydrolysis. The method is based on the measurement of absorbances of 2-Ap and Pi at 300 and 360 nm, respectively, and the calculations are based on the binary method. The absorbances of both compounds obey Beer-Lambert 's law over the concentration range of 5-25 µg L-1 with good linearity (r2>0.99). The recoveries are with in 100.8- 106.4% for Pi and are within 96.4-98.9% for 2- Ap. Precision is good with acceptable limits of detection (LOD) and quantitation (LOQ) for both compounds. The method has been applied for the determination of Pi and 2-Ap in piroxicam capsules. The average content of two different brands of piroxicam is 97.4 and 98.5% (n = 3), which complies with the USP 26 (92.5- 107.5%). Under the stress condition (refluxing with 0.1 N HCI), the percentages of piroxicam decrease from 100% (0 h) to 18.9% (21 h) and 2-Ap increase from 0% (0 h) to 63.6% (21 h)

Exploring chip-capillary electrophoresis-laser-induced fluorescence field-deployable platform flexibility: Separations of fluorescent dyes by chip-based non-aqueous capillary electrophoresis

Microfluidic chip electrophoresis (chip-CE) is a separation method that is compatible with portable and on-site analysis, however, only few commercial chip-CE systems with laser-induced fluorescence (LIF) and light emitting diode (LED) fluorescence detection are available. They are established for several application tailored methods limited to specific biopolymers (DNA, RNA and proteins), and correspondingly the range of their applications has been limited. In this work we address the lack of commercially available research-type flexible chip-CE platforms by exploring the limits of using an application-tailored system equipped with chips and methods designed for DNA separations as a generic chip-CE platform - this is a very significant issue that has not been widely studied. In the investigated Agilent Bioanalyzer chip-CE system, the fixed components are the Agilent chips and the detection (LIF at 635nm and LEDIF at 470nm), while the chemistry (electrolyte) and the programming of all the high voltages are flexible. Using standard DNA chips, we show that a generic CE function of the system is easily possible and we demonstrate an extension of the applicability to non-aqueous CE (NACE). We studied the chip compatibility with organic solvents (i.e. MeOH, ACN, DMF and DMSO) and demonstrated the chip compatibility with DMSO as a non-volatile and non-hazardous solvent with satisfactory stability of migration times over 50h. The generic CE capability is illustrated with separations of fluorescent basic blue dyes methylene blue (MB), toluidine blue (TB), nile blue (NB) and brilliant cresyl blue (BC). Further, the effects of the composition of the background electrolyte (BGE) on the separation were studied, including the contents of water (0-30%) and buffer composition. In background electrolytes containing typically 80mmol/L ammonium acetate and 870mmol/L acetic acid in 100% DMSO baseline separation of the dyes were achieved in 40s. Linearity was documented in the range of 5-28μmol/L, 10-100μmol/L, 1.56-50nmol/L and 5-75nmol/L (r2 values in the range 0.974-0.999), and limit of detection (LOD) values were 90nmol/L, 1μmol/L 1.4nmol/L, and 2nmol/L for MB, TB, NB and BC, respectively. © 2013 Elsevier B.V

Capillary Electrophoresis of Tropane Alkaloids and Glycoalkaloids Occurring in Solanaceae Plants

This chapter examines the role of capillary electrophoresis (CE) in the separation of tropane alkaloids, glycoalkaloids, and closely related compounds that have either pharmaceutical value or toxicological effects on humans. The latest significant developments in CE analysis have been selected and critically discussed. When the conventional CE mode was found unable to provide an acceptable selectivity towards the analytes, the addition of either an organic solvent, a chiral selector, or a surfactant to the running buffers was exploited. Likewise, nonaqueous CE (NACE) was also employed to increase solute solubilities and for a better compatibility of this media with mass spectrometry. It turns out that, upon selecting the most appropriate experimental conditions, the CE separation of tropane alkaloids and steroidal glycoalkaloids of Solanaceae plants was successfully accomplished. All major steps involved in the separation and detection of these secondary metabolites in complex samples are described and the relevant aspects of each application are examined with emphasis on the main aspects entailed a typical assay. More applications have yet to be developed in order to encourage more labs to exploit the tremendous potential of capillary electrophoresis