VALIDATION OF STABILITY INDICATING RP-HPLC METHOD FOR THE SIMULTANEOUS ESTIMATION OF TELMISARTAN AND HYDROCHLOROTHIAZIDE CONTENT IN BULK AND PHARMACEUTICAL DOSAGE FORM

A simple, accurate, precise and rapid stability indicating reverse phase High performance chromatography method was used for estimation of Telmisartan and Hydrochlorothiazide in bulk and fixed-dose combination solid oral dosage form. The proposed analytical method has been validated for specificity, Linearity, Accuracy, Precision and Robustness. The chromatography was achieved in a GL science, Inertsil C8 (Length 125x Diameter 4.0mm Particle size 5µm) column with gradient flow. The optimal chromatographic condition consisted of mobile phase pH 3.0 at a flow rate of 1.2mL/min, with a column temperature of 40°C, run time 14 minutes and detector wavelength of 270nm.

The importance of sound velocity determination for bathymetric survey

Bathymetric surveys are carried out whenever there is a need to know the exact morphological trend of the seabed. For a correct operation of the echo sounder, which uses the principle of acoustic waves to scan the bottom and determine the depth, it is important to accurately determine the sound velocity in water, as it varies according to specific parameters (Density, Temperature, and Pressure). In this work, we want to analyse the role of sound velocity determination in bathymetric survey and its impact on the accuracy of depth measurement. The experiments are conducted on data set provided by “Istituto Idrografico della Marina Militare Italiana” (IIM), the official Hydrographic Office for Italy, and acquired in the Ligurian sea. In our case, the formulas of Chen & Millero (UNESCO), Medwin, and Mackenzie were applied. The introduction of errors on chemical-physical parameters of the water column (Temperature, Pressure, Salinity, Depth) simulating inaccurate measurements, produces considerable impacts on sound velocity determination and subsequently a decrease of the depth value accuracy. The results remark the need to use precise probes and accurate procedures to obtain reliable depth data.

Quantification and Stability Indicating Method Development and Validation of Vismodegib in Bulk and Pharmaceutical Dosage Form by Ultra Performance Liquid Chromatography

Background: Vismodegib (VMD) is a drug of choice for the treatment of basal-cell carcinoma. Present studies carried out to estimate VMD by RP-UPLC technique and to develop a simple, précised, accurate method for routine analysis. Methods: For this purpose Chromatographic conditions used were stationary phase STD BEH C18 column (100 mm x 2.1 mm, 1.8m), a mixture of Methanol:KH2PO4 taken in the ratio 50:50%v/v as a mobile phase with a pH 7.4 and flow rate was maintained at 0.3ml/min, detection wave length was Acquity TUV 254nm, column temperature was set to 30oC and diluent was mobile phase, Conditions were finalized as optimized method. Results: System suitability parameters were studied by injecting the standard six times. Linearity study was carried out between 25% to150% (37.5-225µg/ml) levels, R2 value was found to be as 0.9992. Precision was found to be 0.6 for repeatability and 0.4 for intermediate precision. LOD and LOQ are 0.33 µg/ml and 0.99 µg/ml respectively and results were well under the acceptance criteria. Conclusion: By using above method assay of marketed formulation was carried out and was found 100.12%. Degradation studies of VMD were done, in all conditions purity threshold was more than purity angle and within the acceptable range. The developed method was simple and can be used for routine analysis.

Microwave Assisted Extraction of Berberine and Preparation of Berberine Hydrochloride from Berberis Aristata Variety of Nepal, and Quantification using RP-HPLC and HPTLC Methods

Berberis aristata a Himalayan woody spiny shrub with yellow flowers and red berries commonly called as Daruharidra in Sanskrit and locally in Nepal is called as Chutro or Chitra. The root and stem are the two parts widely used in traditional medicines of India and China. Berberine is the key active ingredient present in stem and root parts. Berberine hydrochloride is the derivative of berberine. The present study aimed to study the microwave assisted extraction of berberine and its conversion into berberine hydrochloride and quantifying by RP-HPLC and HPTLC methods.In the present paper we have mentioned microwave assisted extraction of berberine and preparation of berberine hydrochloride in detail. Berberine extracted from roots of Berberis aristata using microwave assisted extraction in 80% ethanol to obtain 20% pure berberine crude by HPTLC densitometry at 350 nm absorption. The crude berberine was further purified to berberine hydrochloride by adding 10% Hcl in aqueous solution of berberine and allowed to crystallize at 5 0C over 24 hours. The crystals were further purified and recrystallized in ethanol and subjected to RP-HPLC. Reverse phase HPLC was carried out on Shimadzu UV detector at wave length of 265 nm using Acetonitrile-0.1% phosphoric acid solution (50:50) (add 0.1g sodium dodecyl sulfonate per 100ml) as the mobile phase; Phenomenex RP-column (250 mm × 4.6 mm, 5 μm), With flow rate 1.0 mL/minute, 5 µL injection volume, column temperature 25 0C for run time of 35 minutes, and retention time of berberine hydrochloride was 12.008 minutes with purity of 82% and recovery of 90% yield obtained.

Stability-indicating method development and validation for the concurrent determination of darunavir, cobicistat, emtricitabine and tenofovir alafenamide by UPLC in bulk and tablet dosage forms

Background Tablet dosage forms containing combination of darunavir a protease inhibitor, cobicistat a cytochrome P450 3A inhibitor, emtricitabine and tenofovir alafenamide which were nucleoside reverse transcriptase inhibitors were approved by USFDA on 1st July 2018 to suppress the viral load in HIV patients. It can be used as a complete regimen for the treatment of HIV-1 infection in adults and paediatric patients weighing at least 40 kg. An UPLC method was developed, and separation was done on SB C8 column of dimensions 50 × 2.1 × 1.8 μ with mobile phase 0.01 N potassium dihydrogen ortho phosphate (pH-4.8) and acetonitrile in 60:40 ratio, at a flow rate of 0.3 mL/min and an injection volume of 2 μL. The column temperature was maintained at 30 °C, and detection wavelength was 267 nm. The method was validated according to ICH guidelines. Results The retention times were 1.031, 1.341, 1.630 and 2.153 min, and they were linear in the concentration range of 1.25–7.5 μg/mL, 18.75–112.5 μg/mL, 25–150 μg/mL and 100–600 μg/mL for tenofovir alafenamide, cobicistat, emtricitabine and darunavir, respectively. The intraday and interday precisions were found to be within acceptable limits. LOD was found to be 0.06 μg/mL, 0.51 μg/mL, 1.31 μg/mL and 3.01 μg/mL, and LOQ was 0.19 μg/mL, 1.54 μg/mL, 3.96 μg/mL and 9.13 μg/mL for tenofovir alafenamide, cobicistat, emtricitabine and darunavir. The correlation coefficients were found to be more than 0.999, and recovery was more than 99.52% indicating the method was accurate. Forced degradation studies reveal that the drugs are unstable under acidic conditions. The method was simple, accurate, precise, stable and can be analysed in less runtime of 4 min. Conclusions The flexibility, accuracy and precision of the developed method ensure its applicability in routine analysis of tablet dosage forms. Graphical Abstract

Analytical Separation of Closantel Enantiomers by HPLC

Closantel is an antiparasitic drug marketed in a racemic form with one chiral center. It is meaningful to develop a method for separating and analyzing the closantel enantiomers. In this work, two enantiomeric separation methods of closantel were explored by normal-phase high-performance liquid chromatography. The influences of the chiral stationary phase (CSP) structure, the mobile phase composition, the nature and proportion of different mobile phase modifiers (alcohols and acids), and the column temperature on the enantiomeric separation of closantel were investigated in detail. The two enantiomers were successfully separated on the novel CSP of isopropyl derivatives of cyclofructan 6 and n-hexane-isopropanol-trifluoroacetic acid (97:3:0.1, v/v/v) as a mobile phase with a resolution (Rs) of about 2.48. The enantiomers were also well separated on the CSP of tris-carbamates of amylose with a higher Rs (about 3.79) when a mixture of n-hexane-isopropanol-trifluoroacetic acid (55:45:0.1, v/v/v) was used as mobile phase. Thus, the proposed separation methods can facilitate molecular pharmacological and biological research on closantel and its enantiomers.

Equivalent Method Development and Cross Validation of Pharmacopoeial Method of Montelukast Sodium

The purpose of this exploration research work article is to develop equivalent method and evaluate its equivalency (Cross validation) against pharmacopoeial method of Montelukast sodium for the evaluation and assessment of process related impurities i.e. Methyl MLK impurity in Montelukast sodium by HPLC method and its principles. The method mentioned in European Pharmacopoeia (EP) and United States Pharmacopoeia (USP) does not sufficiently separates impurity C and impurity D , as these impurities elutes under the main peak and the pharmacopoeial methods were also not able to detect the Methyl MLK impurity which is not listed in USP monograph. So our prime design of experiment is to develop of new high-performance liquid chromatographic (HPLC) method which eliminates the drawback of two pharmacopoeial methods and this proposed created strategy is fit for recognition and detection of Methyl MLK impurity and separation of all process related impurities of Montelukast sodium mentioned in EP and USP monographs. An efficient strategy screening and scouting in which various C-18 columns were tried and tested. LUNA C-18 column utilized in RP HPLC mode ended up being the phenomenal decision for the technique streamlining. The proportion of acetonitrile and trifluoroacetic acid (TFA) in water and in the mobile phase, column temperature, flow rate and diluents were considered as basic strategy boundary. The method developed equivalency was checked in terms of Specificity, LOD, Quantitation (LOQ), Precision, Linearity, Relative response factor (RRF), and Accuracy.

Determination of Levamisole and Mebendazole and Its Two Metabolite Residues in Three Poultry Species by HPLC-MS/MS

A high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed to simultaneously analyze levamisole (LMS) and mebendazole (MBZ) and its two metabolites, 5-hydroxymebendazole (HMBZ) and 2-amino-5-benzoylbenzimidazole (AMBZ), in poultry muscle (chicken, duck and goose). In the sample preparation process, basic ethyl acetate was used as the extraction agent, and the extracted samples were back-extracted with hydrochloric acid, purified by Oasis MCX solid-phase extraction (SPE) cartridges, and reconstituted in the initial mobile phase after being blown dry with nitrogen. Chromatographic separation was performed on an Xbridge C18 column (4.6 mm × 150 mm, 5 μm) with 0.1% formic acid in water and acetonitrile as the mobile phases, and gradient elution was performed at a flow rate of 0.6 mL/min and a column temperature of 35 °C. In blank poultry muscle samples, the spiked concentrations of LMS, MBZ, HMBZ, and AMBZ were within the range of the limit of quantitation (LOQ) to 25 μg/kg. The peak areas of the four target drugs had a good linear relationship with the concentration, and the determination coefficient (R2) values were higher than 0.9990. The average recoveries of LMS, MBZ, HMBZ, and AMBZ were 86.77–96.94%; the intraday relative standard deviations (RSDs) were 1.75–4.99% at LOQ, 0.5 maximum residue limit (MRL), 1.0 MRL, and 2.0 MRL; the interday RSDs were 2.54–5.52%; and the LODs and LOQs were 0.04–0.30 μg/kg and 0.12–0.80 μg/kg, respectively.

Therapeutic monitoring of mycophenolic acid in renal transplanted patients by a validated HPLC method

Introduction: Mycophenolate mofetil and its active metabolite mycophenolic acid are routinely used as immunosuppressant drugs in solid organ transplantation in a fixed daily dose regimen in association with cyclosporine, tacrolimus and steroids. Therapeutic drug monitoring for mycophenolic acid concentration has been suggested to optimize outcomes by reducing rejection and drug related toxicities in clinical renal transplantation. Aim: To determine the predose concentration of mycophenolic acid in renal transplanted patients by a validated proposed high-performance liquid chromatography (HPLC) method and to estimate the interindividual variability based on the therapeutic target. Materials and methods: An HPLC method combined with protein precipitation has been validated for mycophenolic acid determination in the human plasma obtained from 21 renal transplant recipients. HPLC analysis was carried out using the chromatographic system Agilent Technologies 1200 DAD. Samples were injected manually, and the compounds were separated on a LiChrosphere® select B C18 analytical column. The mobile phase was 45:55 (v/v) acetonitrile-buffer phosphate, pH 2.5, flow rate of 1.0 mL/min and column temperature of 30°C. Detection was performed at 215 nm. Whole blood samples were collected into vacutainers containing EDTA and separated at 6000 g for 10 minutes. A 200-μL aliquot of patient plasma was transferred to a tube, followed by addition of 10 μL of naproxen as internal standard and 400 μL of acetonitrile (v/v) as a protein precipitating agent. Each tube was vortex-mixed for 30 sec and then centrifuged for 10 min at 10000 rpm. 20 μL of the supernatant was injected into the HPLC system for analysis. Results: The method showed appropriate linearity for MPA with correlation coefficient greater than 0.999. High inter-patient variability is observed with 18% of patients within the target trough concentration range, 27% of patients below the target trough concentration range and 54% over the range with risk of toxicity. Conclusions: Therapeutic monitoring of MPA might contribute to a better management of renal transplant recipient with the goal of optimizing therapeutic regimens in order to reduce the risk of rejection and MPA‐related toxicity.

Depth- and temperature-specific fatty acid adaptations in ctenophores from extreme habitats

Animals are known to regulate the composition of their cell membranes to maintain key biophysical properties in response to changes in temperature. For deep-sea marine organisms, high hydrostatic pressure represents an additional, yet much more poorly understood, perturbant of cell membrane structure. Previous studies in fish and marine microbes have reported correlations with temperature and depth of membrane-fluidizing lipid components, such as polyunsaturated fatty acids. Because little has been done to isolate the separate effects of temperature and pressure on the lipid pool, it is still not understood whether these two environmental factors elicit independent or overlapping biochemical adaptive responses. Here, we use the taxonomic and habitat diversity of the phylum Ctenophora to test whether distinct low-temperature and high-pressure signatures can be detected in fatty acid profiles. We measured the fatty acid composition of 105 individual ctenophores, representing twenty-one species, from deep and shallow Arctic, temperate, and tropical sampling locales (sea surface temperature -2° to 28° C). In tropical and temperate regions, remotely operated submersibles (ROVs) enabled sampling down to 4000 meters. Among specimens with body temperatures 7.5°C or colder, depth predicted fatty acid unsaturation level. In the upper 200 m of the water column, temperature predicted fatty acid chain length. Taken together, our findings suggest that lipid metabolism may be specialized with respect to multiple physical variables in diverse marine environments. Largely distinct modes of adaptation to depth and cold imply that polar marine invertebrates may not find a ready refugium from climate change in the deep.