A simple, specific, accurate, precise stability indicating reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the simultaneous determination of pyridoxine hydrochloride (PYH) and meclizine hydrochloride (MEH). An isocratic separation of PYH and MEH were achieved on C 18, 250 × 4.6 mm ID, 5 m particle size columns at column oven temperature 37 ∘ C with a flow rate of 0.5 mL min −1 and using a diode array detector to monitor the detection at 254 nm. The mobile phase consisted of buffer : acetonitrile : trifluoroacetic acid at a ratio of 30 : 70 : 0.1 (v/v). The retention times of PYH and MEH was found to be 5.25 and 10.14 min, respectively. Suitability, specificity, linearity, accuracy, precision, stability, and sensitivity of this method for the quantitative determination of the drugs were proved by validation in accordance with the requirements laid down by International Conference on Harmonization (ICH) Q2 (R1) guidelines. The proposed method is reliable and robust and can be used as quality control tool for the estimation of these drugs in combined pharmaceutical solid dosage forms.

Polycyclic aromatic hydrocarbons (PAHs) are semivolatile organic compounds (SVOCs) categorized as persistent organic pollutants (POPs). PAHs are ubiquitous in terrestrial, atmospheric, and particularly aquatic environments throughout the world and have been detected in lakes, ground waters, and rivers. This research work involved the analysis of five PAHs, anthracene, fluorene, naphthalene, phenanthrene, and pyrene, in water sample collected from the river Buriganga, Bangladesh. The extraction of water samples was carried out by reversed phase solid-phase extraction (RP-SPE) technique with C-18 SPE cartridges. A solvent mixture of dichloromethane and hexane (1 : 2) with a flow rate of 0.5 mL/min was used as eluent. Percentage recoveries of five PAHs for this technique were in the range of 81.47 ± 1.16 to 98.60 ± 0.61%. PAHs quantification was achieved by using an ion trap gas chromatography mass spectrometer (GC-MS) interfaced to gas chromatography (GC) equipped with a fused silica capillary column. Helium was used as carrier gas with a flow rate of 1.0 mL/min. The commonly detected PAH compounds in the river water were anthracene, naphthalene, and phenanthrene at the concentration ranges of 0.451 to 3.201, 0.033 to 3.1131, and 0.320 to 2.546 μg/mL, respectively. The results reflect that PAHs presented in this river water were mostly from petrogenic and pyrogenic sources.

The purpose of this study was to develop and validate a new reversed phase high performance liquid chromatographic (RP-HPLC) method to quantify in vitro dissolution assay of rabeprazole sodium in pharmaceutical tablet dosage form. Method development was performed on C 18, 100 × 4.6 mm ID, and 10 μm particle size column, and injection volume was 20 μL using a diode array detector (DAD) to monitor the detection at 280 nm. The mobile phase consisted of buffer: acetonitrile at a ratio of 60 : 40 (v/v), and the flow rate was maintained at 1.0 mL/min. The method was validated in terms of suitability, linearity, specificity, accuracy, precision, stability, and sensitivity. Linearity was observed over the range of concentration 0.05–12.0 μg/mL, and the correlation coefficient was found excellent >0.999. The method was specific with respect to rabeprazole sodium, and the peak purity was found 99.99%. The method was precise and had relative standard deviations (RSD) less than 2%. Accuracy was found in the range of 99.9 to 101.9%. The method was robust in different variable conditions and reproducible. This proposed fast, reliable, cost-effective method can be used as quality control tool for the estimation of rabeprazole sodium in routine dissolution test analysis.

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Background The present work describes the development and validation of a new, specific, accurate, and precise stability-indicating RP-HPLC method for the simultaneous estimation of Esomeprazole (ESP) and Naproxen (NAP) in modified-release bi-layer tablet dosage form. Analytical Quality by Design concept was implemented through the method development exercise to establish the robustness of the method. Results Method development was performed on C18, 250 × 4.6 mm ID, and 5 µm particle size column with 10 µl injection volume using a photodiode array (PDA) detector to monitor the detection at 280 nm. The mobile phase consisted of the buffer: methanol at a ratio of 50: 50 (v/v), and the flow rate was maintained at 1.5 ml/min, and the column oven temperature was maintained at 30 °C. The retention times for NAP and ESP were found 5.9 ± 0.1 and 8.9 ± 0.1 min, respectively. The method was validated in terms of system suitability, specificity, accuracy, linearity, precision, and solution stability. Linearity was observed over the range of concentration 8–12 µg/ml for ESP and 200–300 µg/ml for NAP, and the correlation coefficient (R2) was found excellent > 0.999. The method was specific to ESP and NAP, and the peak purity was found 99.97% for ESP and 100.00% for NAP. The method was precise and had %RSD less than 2. Recovery study for accuracy with placebo was found in the range of 99.63–100.36% for ESP and 99.91–100.43% for NAP. Conclusion This proposed fast, reliable, cost-effective method can be used as a quality control tool for the simultaneous determination of Esomeprazole and Naproxen in routine laboratory analysis. Graphical Abstract