Isolation and Structural Elucidation of Impurity in Sulfonamide Intermediate of Glyburide

A reproducible isolation method by Reverse Phase (RP) preparative HPLC technique for the isolation of one crucial impurity at 1.65 RRT (Relative Retention Time) in sulfonamide stage of Glyburide API (Active Pharmaceuticals Ingredient) was developed. Preparative chromatography was done on Luna C8, 10µm (250 mm x 21.2mm) preparative HPLC column with acetonitrile: water in 70:30 % v/v proportion as a mobile phase and 8 ml/min as a flow rate. This impurity was detected at 300 nm UV-wavelength maximum. This impurity was isolated from synthesized crude impurity of sulfonamide stage of Glyburide substance by preparative HPLC by injecting 50 mg/ml concentration over 5 ml fixed loop. Isolated impurity was elucidated as N-methyl impurity of sulfonamide intermediate of Glyburide API by means of chromatographic and spectral data. Structural elucidation carried out by spectral data was reviewed. This impurity was analyzed by reverse phase HPLC for purity analysis. A Inertsil C8 (250 x 4.6) mm, 5µ particle size was employed for separation. The mobile phase consisted of Water: Acetonitrile: Methanol in the ratio of 60:15:25 % v/v. The flow rate was set at 1 ml/min. Detection was carried out at 300 nm. 10µL of 2 mg/ml concentration of sample in methanol was injected. The column oven temperature was at 25°C.

Analytical Method Development and Validation for Estimation of Mifepristone in Pure and Pharmaceutical Dosage Form

Mifepristone structurally belongs to the class of anti-progesterone steroids, which are used as an oral contraceptive. The reverse phase HPLC method was designed in a simplified and rapid way for the estimation of Mifepristone in bulk as well as tablets. The method was established using a Kromasil C18 column of dimensions of 250mm×4.6mm and a particle size of 5m.The used mobile phase was Acetonitrile: Water (70:30, v/v). The pump was pumped at 1 ml/min at a temperature of about 30 ± 2 °C and the eluted analyte was identified at 305 nm. Mifepristone eluted with a mean retention time of 6.27 minutes. The intended method was validated as per ICH (International Council for Harmonisation) guidelines, indicating a high degree of specificity, system suitability, accuracy, precision, and robustness. The LOD (Limit of detection) was found to be 0.7238 ppm and the limit of measurement was 0.9562 ppm. The method linearity was found to be between 1-6µg/ml, with an R2 of 0.9923. In accuracy studies, the percent recovery was found to be between 99.39% - 100.50%. The method was discovered to be precise as the values of the percent RSD were found to be less than 2.0% for both intraday and interday. The method was discovered to be reliable and robust. Mifepristone in marketed pharmaceutical tablet dosage form was effectively quantified using the established Reverse Phase HPLC method.

Optimasi Sintesis Ligan Diheksilditiofosfat (DHDTP) Menggunakan Response Surface Method (RSM)

Dihexyldithiophosphate (DHDTP) ligand is one of the homologues of dialkyldithiophosphate which is potentially better as an extractant in solvent extraction. The longer the chain in the dialkyldithophosphate compound, ability to dissolve into the organic phase is increasing compared to the shorter chain. The purpose of this study is to synthesize DHDTP ligands and find out the optimum reaction conditions to produce DHDTP ligands with optimal purity using the BoxBehnken (BBD) response surface method (RSM). DHDTP ligands are synthesized from P2S5 by reflux after addition of n-hexanol under a nitrogen gas environment. Ammonium carbonate is added to the reflux to pH 7, then evaporated to remove the solvent. The synthesized DHDTP ligand was then purified by column chromatography with a mobile phase methanol : aquadest (2.5% gradient). DHDTP ligands were examined for purity using a reverse phase HPLC with a mobile phase methanol: aquadest 3: 2. The purity of the best DHDTP synthesis results obtained was 87.34%. The DHDTP ligand formed was characterized to confirm the structure of its ligand compound by using a UV spectrophotometer in which the synthesis product showed maximum absorption at a wavelength of 212 nm and mass spectroscopy ES- with m / z 297.1687.

RP-HPLC Method for Quantification of Emtricitabine and Tenofovir Alafenamide Fumarate Drug Substance and Tablet Dosage Form

Aim: The primary objective of the research work is to develop a effective, sensitive, economical and simple reverse phase HPLC method to estimate Emtricitabine and tenofovir alafenamide fumarate in its pure and binary mixture of tablets. Study Design: HPLC based Quantification Studies. Place and Duration of Study: 1Department of Chemistry, Acharya Nagarjuna University,Guntur, Andhra Pradesh between April 2019 and August 2020. Methodology: Separation of the analytes were done by using Eclipse XDB-Phenyl (250 x 4.6mm, 5µ,100 A0) column and a mobile phase ratio of 30:10:70 percentage of 0.1% trifluoro acetic acid: acetonitile: methanol at a flow rate of 1 ml/min. The injected standard and sample solutions were detected 260nm wavelength. Results: The retention time of Emtricitabine and tenofovir alafenamide fumarate were found at 2.3min and 2.8 min respectively. The method has good linearity range about 50 to 150µg/ml of Emtricitabine and 6.5 to 19.5 µg/ml of tenofovir alafenamide fumarate. The method has validated as per ICH guidelines and all the validation parameterwere satisfy the ICH Q2 specification acceptance limits Conclusion: The developed method said to be highly sensitive, accurate, specific and robust, therefore this method has high probability to adopt in pharmaceutical industry for regular analysis of Emtricitabine and tenofovir alafenamide.

Streamlined three step total vitamin C analysis by HILIC-UV for laboratory testing

Objectives In the clinical setting, the analysis and quantification of vitamin C (ascorbic acid) poses several challenges including analyte instability and poor retention by reverse phase HPLC systems. In this article we describe a rapid hydrophilic interaction chromatography ultraviolet method for the measurement of total vitamin C in plasma which overcomes these issues. Methods Ascorbic acid and the internal standard were separated under isocratic conditions using a Waters BEH-Amide column and a mobile phase containing 0.005 M potassium phosphate in 80% acetonitrile. Results The proposed method was validated and showed good precision (coefficient of variation <5%), accuracy (>99%), and analyte stability after extraction (>24 h). Conclusions The simple sample preparation allows full automation and rapid analytical run times of the assay and is therefore suitable for a high-throughput clinical chromatography laboratory.

Identification, mapping and relative quantitation of SARS-CoV-2 Spike glycopeptides by Mass-Retention Time Fingerprinting

We describe an analytical method for the identification, mapping and relative quantitation of glycopeptides from SARS-CoV-2 Spike protein. The method may be executed using a LC-TOF mass spectrometer, requires no specialized knowledge of glycan analysis and exploits the differential resolving power of reverse phase HPLC. While this separation technique resolves peptides with high efficiency, glycans are resolved poorly, if at all. Consequently, glycopeptides consisting of the same peptide bearing different glycan structures will all possess very similar retention times and co-elute. Rather than a disadvantage, we show that shared retention time can be used to map multiple glycan species to the same peptide and location. In combination with MSMS and pseudo MS3, we have constructed a detailed mass-retention time database for Spike glycopeptides. This database allows any accurate mass LC-MS laboratory to reliably identify and quantify Spike glycopeptides from a single overnight elastase digest in less than 90 minutes.

Isocratic Reverse-Phase HPLC Method for Determination of Aspirin, Paracetamol, and Naproxen

Nonsteroidal anti-inflammatory drugs (NSAIDs), which block the activity of cyclooxygenase (COX) isoenzymes and inhibit the synthesis of prostaglandin, have been used for pain relief. We have developed a method to separate a mixture of three NSAIDs, such as aspirin, paracetamol, and naproxen, using reverse-phase high-performance liquid chromatography (RP-HPLC). An isocratic mobile phase consisting of acidic water and acetonitrile was selected to run at a low flow rate, such as 0.8 mL/min. The mixture of three NSAIDs was injected at a low volume into a C18 column that was 150 mm in length and characterized using a UV detector at 230 nm. We identified three peaks in the chromatogram indicating the three compounds. The elution time of the peaks was less than 10 minutes. To identify multiple peaks on the isocratic flow using a short column, further studies are required regarding the proposed method to generate microfluidic devices for nanoLC.