Development & Validation of HPLC method for simultaneous estimation of Drotaverine & Omeprazole

A simple and accurate method was developed for simultaneous estimation of Drotaverine & Omeprazole. The chromatography parameters includes stainless steel column Develosil ODS HG-5 RP C18, 5m, 15cmx4.6mm i.d and acetonitrile: potassium dihydrogen phosphate buffer (0.02M, pH 3.0) (55:45v/v) as mobile phase at a flow rate (1.0 ml/minute). The determinations were performed using UV-Vis detector set at 273 nm. The developed HPLC method showed specificity and selectivity with good precision and accuracy, which makes it very suitable for quantification of Drotaverine & Omeprazole.

Stability indicating RP-HPLC method development for docetaxel trihydrate

The purpose of present study was to develop RP-HPLC method for estimation of docetaxel trihydrate which should be a suitable, simple, precise, accurate, robust, and reproducible. The samples were assayed by the Shimadzu HPLC instrument - LC-20AD (Japan) equipped with Shimadzu SPD-M20A UV-VIS detector operated at wavelength of 230 nm. The binary gradiant pump was used for the analytical method development. The reverse phase stainless steel column (150 × 4.6 mm) packed with 5 μm particles (C-8, LiCrosphore® 100, Germany) was used to take chromatograph. A mobile phase consisting of acetonitrile/phosphate buffer 20 mM, (45:55, v/v), pH 3.5 adjusted with o-phosphoric acid at a flow rate of 1 mL/min. The method was validated by system suitability and reproducibility. The linearity was also determined using samples with five different concentrations of 20, 40, 60, 80 and 100 µg/mL. The results of the study showed that the developed RP-HPLC method is simple and robust which is useful for the estimation of docetaxel trihydrate in bulk drug and in pharmaceutical dosage form. The results of stability show that the method has stability over a period of 48 h at room temperature. Keyword: Docetxel trihydrate, RP-HPLC method, validation, stability

Extraction Efficiency of a Commercial Espresso Machine Compared to a Stainless-Steel Column Pressurized Hot Water Extraction (PHWE) System for the Determination of 23 Pharmaceuticals, Antibiotics and Hormones in Sewage Sludge

Two green chemistry extraction systems, an in-house stainless-steel column Pressurized Hot Water Extraction system (PHWE) and a commercially available Espresso machine were applied for analysing 23 active pharmaceutical ingredients (APIs) in sewage sludge. Final analysis was performed on UPLC-MS/MS using two different chromatographic methods: acid and basic. When analysing all 23 APIs in sewage sludge both extraction methods showed good repeatability. The PHWE method allowed for a more complete extraction of APIs that were more tightly bound to the matrix, as exemplified by much higher concentrations of e.g., ketoconazole, citalopram and ciprofloxacin. In total, 19 out of 23 investigated APIs were quantified in sewage sludge, and with a few exceptions the PHWE method was more exhaustive. Mean absolute recoveries of 7 spiked labelled APIs were lower for the PHWE method than the Espresso method. Under acid chromatographic conditions mean recoveries were 16% and 24%, respectively, but increased to 24% and 37% under basic conditions. The difference between the PHWE method and the Espresso method might be interpreted as the Espresso method giving higher extraction efficiency; however, TIC scans of extracts revealed a much higher matrix co-extraction for the PHWE method. Attempts were made to correlate occurrence of compounds in sewage sludge with chemical properties of the 23 APIs and there are strong indications that both the number of aromatic rings and the presence of a positive charge is important for the sorption processes to sewage sludge.

Preparation and evaluation of a green solvent-based molecularly imprinted monolithic column for the recognition of proteins by high-performance liquid chromatography

A protein-based molecularly imprinted monolithic column was synthesized based on ionic liquids (ILs) and deep eutectic solvents (DESs) in a stainless steel column (50 mm × 4.6 mm id).

Experimental Investigation Into Creep Buckling of a Stainless Steel Plate Column Under Axial Compression at Extremely High Temperatures

This study aims to investigate the creep buckling behavior of a stainless steel column under axial compressive loading at extremely high temperatures. Creep buckling failure time of a slender column with a rectangular cross section was experimentally measured under three different temperature conditions, namely, 800, 900, and 1000 °C. At each temperature, axial compressive loads with magnitudes ranging between 15% and 80% of the buckling loads were applied to the top of the column, and the creep buckling failure time was measured to examine its relationship with the compressive load. The stainless steel column was found to fail within a relatively short time compared to that of creep deformation under tensile loading. An increase in the temperature of the column was found to accelerate creep buckling failure. The in-plane and out-of-plane column displacements, which respectively, corresponded to the axial and lateral displacements, were monitored during the entire experiment. The creep buckling behavior of the column was also visualized by a high-speed camera. Based on the Larson–Miller parameters (LMP) determined from the experimental results, an empirical correlation for predicting the creep buckling failure time was developed. Another empirical correlation for predicting the creep buckling failure time based on the lateral deflection rate was also derived.

Preparation of a restricted access material–macroporous hybrid monolithic column – for on-line solid-phase extraction of the sulfonamides residues from honey

A novel RAM–HMC with superior enrichment and clean-up efficiency was prepared by an in situ method in a stainless-steel column, and used as a pre-column for on-line solid-phase extraction of sulfonamides residues from honey.

Quantitative Analysis of Resorcinol from Marketed Hair Tonic Using Liquid Chromatographic Technique

Quantitative estimation of resorcinol from marketed pharmaceutical formulation has been reported in this study. Resorcinol as a pharmaceutical ingredient has a broad spectrum of application but its application is limited due to its toxic side effects. Method for the accurate estimation of resorcinol is therefore essential. In the current study we have developed a chromatographic technique for its estimation from a marketed hair tonic meant for the treatment of several dermatological diseases of the scalp. A stainless steel column 25 cm in length and 4 mm internal diameter packed with octadecylsilane (5 µm) was used for this purpose. The mobile phase was a mixture of phosphate buffer of pH 2.8 and acetonitrile. The flow rate was 0.6 mL·min−1 and the detection wavelength was 280 nm. The method was found to be linear between concentration range 10.28 µg·mL−1 to 71.96 µg·mL−1 with r2 value 0.999. The accuracy of the method and the intraday and interday precession study presents the applicability of the method for the estimation of resorcinol from any pharmaceutical and cosmetic product containing resorcinol.

Separation ofcis- andtrans-Asarone fromAcorus tatarinowiiby Preparative Gas Chromatography

A preparative gas chromatography (pGC) method was developed for the separation of isomers (cis- andtrans-asarone) from essential oil ofAcorus tatarinowii. The oil was primarily fractionated by silica gel chromatography using different ratios of petroleum ether and ethyl acetate as gradient elution solvents. And then the fraction that contains mixture of the isomers was further separated by pGC. The compounds were separated on a stainless steel column packed with 10% OV-101 (3 m × 6 mm, i.d.), and then the effluent was split into two gas flows. One percent of the effluent passed to the flame ionization detector (FID) for detection and the remaining 99% was directed to the fraction collector. Two isomers were collected after 90 single injections (5 uL) with the yield of 178 mg and 82 mg, respectively. Furthermore, the structures of the obtained compounds were identified ascis- andtrans-asarone by1H- and13C-NMR spectra, respectively.