A Stability Indicating Method Development and Validation for The Simultaneous Estimation of Emtricitabine, Tenofovir Alafenamide and Doultegravir in Pharmaceutical Formulation by Ultra Performance Liquid Chromatography

A Precise, specific, linear, accurate and robust technique used to be developed for the simultaneous estimation of the, Emtricitabine, Tenofovir alafenamide and Doultegravir in pill dosage structure and Validated as per ICH Validation guidelines. Method was once optimised with the useful resource of Acquity BEH C18 125A° (100 × 2.1 mm, 1.7μ) column at a flow rate of 0.6ml/min, Mobile part was as soon as pH 3.8 Buffer, Methanol and Acetonitrile (50:40:10 respectively). The Column Oven temperature used to be maintained at 35°C and working wave dimension used to be selected at 274nm. The retention times of Emtricitabine, Tenofovir Alafenamide and Doultegravir have been determined to be 3.77, 6.34 and 7.67minutes respectively. The % RSD of the Emtricitabine, Tenofovir Alafenamide and Doultegravir had been and located to be 0.27%, 1.24% and 0.11% respectivelyIn Method precision Parameter, % Assay had been determined ninety five to 105.0% and p.c Recovery had been acquired as 98.9%, 100.4% and 100.0% for Emtricitabine, Tenofovir Alafenamide and Doultegravir respectively. Linearity was as soon as acquired as 0.999, 0.999 and 0.999 for Emtricitabine, Tenofovir Alafenamide and Doultegravir respectively. Analytical Range used to be determined from the linearity and accuracy for Emitricitabine used to be 50µg/mL to 150µg/mL, Tenofovir Alafenamide used to be as soon as 6.25µg/mL to 18.75µg/mL and Doultegravir was as soon as 12.5µg/mL to 37.5µg/mL.

Simultaneous Determination of Candesartan and Hydrochlorothiazide in Human Plasma by HPLC-MS/MS

Introduction. Combined drugs have the greatest efficacy and safety in arterial hypertension treatment. The combination of candesartan and hydrochlorothiazide (AT1-receptor antagonist and a thiazide diuretic, respectively) provides high efficiency of antihypertensive combination therapy, therefore it is widely used in medical practice. Developing a method for simultaneous determination of candesartan and hydrochlorithiazide in human blood plasma is necessary for performing the analytical part of pharmacokinetic studies and bioequivalence studies of multicomponent drugs.Aim. The aim of this study is to develop a method for quantitative determination of candesartan and hydrochlorothiazide in human plasma by high-performance liquid chromatography – tandem mass spectrometry (HPLC-MS/MS) for further bioequivalence studies.Materials and methods. Determination of candesartan and hydrochlorothiazide in human plasma by HPLC-MS/MS. The samples were processed by acetonitrile protein precipitation. Internal standard: mixed solution of valsartan and indapamide. Mobile phase: 0.1 % formic acid solution in water (eluent A), 0.1 % formic acid in acetonitrile (eluent B). Column: Phenomenex Luna Phenyl-Hexyl, 50x4.6 mm, 5 μm. Analytical range: 2.00– 300.00 ng/mL for candesartan, 2.00–200.00 ng/mL for hydrochlorothiazide in human plasma. Ionization source: electrospray ionization. Detection conditions: 441.10 → 192.00 m/z, 441.10 → 263.15 m/z (candesartan), 295.85 → 269.00 m/z (hydrochlorothiazide), 436.00 → 207.05 m/z (valsartan), 363.85 → 132.10, 363.85 → 189.00 m/z (indapamide).Results and discussion. This method was validated by selectivity, matrix effect, calibration curve, accuracy, precision, spike recovery, the lower limit of quantification, carry-over effect and stability. The developed method meets the requirements for conducting bioequivalence studies of medicinal products within the framework of the Eurasian Economic Union.Conclusion. The analytical range was 2.00–300.00 ng/mL for candesartan, 2.00–200.00 ng/mL for hydrochlorothiazide in human plasma. The method was applied in BE study of the combination of candesartan and hydrochlorothiazide.

Adsorption-Luminescent Determination of Y(III) Using 8-oxyquinoline Derivatives Fixed on the Silica Surface

Silicas, sequentially modified with polyhexamethylene guanidine and 8-hydroxyquinoline‑5-sulfonic acid (SiO2-PHMG‑oxine) or 7-iodine‑8-hydroxyquinoline‑5-sulfonic acid (SiO2-PHMG‑ferron), have been proposed for the adsorption-luminescent determination of Y(III) in natural waters. Complex compounds of Y(III) are formed on the surface of adsorbents during adsorption from solutions at pH 6–7, which luminesce in a yellow-green color (λlum = 485 nm (SiO2-PHMG‑oxine) and λlum = 490 nm (SiO2-PHMG‑ferron)). This is the basis for the method of its sorption-luminescent determination. The detection limit of Y(III), calculated according to the 3s criterion, is 1 μg/L (SiO2-PHMG‑oxine) and 2 μg/L (SiO2-PHMG‑ferron), the analytical range is 4–400 μg/L (SiO2-PHMG‑oxine) and 6–500 μg/L (SiO2-PHMG‑ferron). The developed methods were tested in the determination of yttrium in the Yenisei and Kacha rivers of the Krasnoyarsk Krai

A rapid and reliable multiplexed LC-MS/MS method for simultaneous analysis of six monoamines from brain tissues

Monoamines are a class of neuromodulators that are crucial for a variety of brain functions, including control of mood, movement, sleep and cognition. From mammals to insects, the nervous system is enriched in monoamines such as dopamine, serotonin and melatonin, analytes which range from being highly polar to non-polar. Here we developed a method using liquid chromatography coupled with mass spectrometry (LC-MS) to quantify in a single run the amounts of six distinct monoamines in extracts from dissected Drosophila and mouse brain tissues. The measured monoamines were dopamine (DA), serotonin (also known as 5-hydroxytryptamine (5-HT)), octopamine (OA, an insect equivalent of norepinephrine), tyramine (TA), melatonin (MT) and N-acetyl-hydroxy-serotonin (NAS). The analytical range of these monoamines was between 0.25 to 5.0 ng/mL.

EXPRESS: Time-resolved fluorescence immunoassay for urine retinol binding protein is more sensitive than polyclonal and monoclonal assays.

Background- Retinol-binding protein4 (RBP) assays using polyclonal antibodies (pRBP) have major problems of non-linearity of dilution and a very small useable dynamic range. Our objective was to develop a specific assay with a wider dynamic range to detect tubular proteinuria. Methods: mRBP (monoclonal capture and second antibody with colorimetric detection) and fRBP, (polyclonal capture and monoclonal second antibody with fluorescence detection) were developed and compared with pRBP. 488 patient samples were collected- 290 samples were analysed by mRBP and 198 samples with fRBP and compared with pRBP. Results: mRBP assay has the advantages of better linearity on dilution and wider analytical range over pRBP. It is limited by poor signal in the patients with albuminuria and glomerular proteinuria and inferior discrimination between patient groups. fRBP had an intra-assay and inter-assay CV of <6% and <8% respectively; and analytical range was 2.3-599 µg/L. fRBP was linear on dilution within the analytical range. Correlation (r) was 0.8722(95% CI 0.7621 to 0.9333, p< 0.0001), Mann-Whitney test revealed no significant difference (U= 18877, n=198, p = 0.5244) asserting that the medians of the two samples were identical. Bland-Altman test between pRBP and fRBP showed a mean negative bias of 16.43(CI -994 to 1027) μg/mmol Conclusion: The combination assay with fluorescence detection (fRBP) proved more discriminatory than a purely monoclonal system especially in patients with significant proteinuria and has advantages of better linearity on dilution and wider analytical range than the existing pRBP assay and compared extremely well with pRBP.

Evaluation of an automated immunoturbidimetric assay for detecting canine C-reactive protein

C-reactive protein (CRP) is a major acute-phase protein, and it is produced by the liver in response to a pro-inflammatory stimulus. Given that human and canine CRP have a similar molecular structure, the assays used for human CRP detection have been used to measure CRP concentrations in dogs. We evaluated the use of a human CRP assay (Biotecnica CRP assay) and validated its application in dogs. We analyzed 91 canine serum samples with a fully automated analyzer. Our validation was based on the evaluation of imprecision, limits of linearity, limits of quantification, and an evaluation of interferences. The new assay was also compared with the Randox CRP assay, a validated assay for the measurement of CRP. Intra- and inter-assay repeatability were <8% and <11%, respectively. The tested assay proportionally measured canine CRP in an analytical range up to 60 mg/L; however, hemoglobin, triglycerides, and bilirubin interfered with the determination. Good agreement, with the presence of proportional systematic bias, was observed between Biotecnica and Randox assays. The Biotecnica CRP assay provides reliable measurement of CRP in canine serum, provided that samples are free of interferents.

A Rapid LC–MS-MS Method for the Quantitation of Antiepileptic Drugs in Urine

Epilepsy is a common neurologic disease that requires treatment with one or more medications. Due to the polypharmaceutical treatments, potential side effects, and drug-drug interactions associated with these medications, therapeutic drug monitoring is important. Therapeutic drug monitoring is typically performed in blood due to established clinical ranges. While blood provides the benefit of determining clinical ranges, urine requires a less invasive collection method, which is attractive for medication monitoring. As urine does not typically have established clinical ranges, it has not become a preferred specimen for monitoring medication adherence. Thus, large urine clinical data sets are rarely published, making method development that addresses reasonable concentration ranges difficult. An initial method developed and validated in-house utilized a universal analytical range of 50–5,000 ng/mL for all antiepileptic drugs and metabolites of interest in this work, namely carbamazepine, carbamazepine-10,11-epoxide, eslicarbazepine, lamotrigine, levetiracetam, oxcarbazepine, phenytoin, 4-hydroxyphenytoin, and topiramate. This upper limit of the analytical range was too low leading to a repeat rate of 11.59% due to concentrations &gt;5,000 ng/mL. Therefore, a new, fast liquid chromatography–tandem mass spectrometry (LC–MS-MS) method with a run time under 4 minutes was developed and validated for the simultaneous quantification of the previously mentioned nine antiepileptic drugs and their metabolites. Urine samples were prepared by solid-phase extraction and analyzed using a Phenomenex Phenyl-Hexyl column with an Agilent 6460 LC–MS-MS instrument system. During method development and validation, the analytical range was optimized for each drug to reduce repeat analysis due to concentrations above the linear range and for carryover. This reduced the average daily repeat rate for antiepileptic testing from 11.59% to 4.82%. After validation, this method was used to test and analyze patient specimens over the course of approximately one year. The resulting concentration data were curated to eliminate specimens that could indicate an individual was noncompliant with their therapy (i.e., positive for illicit drugs) and yielded between 20 and 1,700 concentration points from the patient specimens, depending on the analyte. The resulting raw quantitative urine data set is presented as preliminary reference ranges to assist with interpreting urine drug concentrations for the nine aforementioned antiepileptic medications and metabolites.

Development of the method for spectrophotometric quantitative determination of the total flavonoids in Bupleurum multinerve herb

The article presents the method for the quantitative determination of flavonoids for the analysis of Bupleurum multinerve herb based on the method of differential spectrophotometry. The optimal conditions for analysis have been determined. They include extractant 40% ethyl alcohol, ratio of raw materials and extractant 1 : 100, extraction time of 60 minutes in the boiling water bath, complexing agent of 1 ml of 2% aluminum chloride. The use of rutin as a standard has been experimentally validated, analytical wavelength is 412 nm. The relative error of the mean result (for n = 9) was 3.20%. Validation studies of the method have shown that it meets the criteria: linearity (r = 0.99988), correctness, specificity, and precision. The analytical range of the method is 8.6726.08 g/ml. The method is recommended for the inclusion into the new edition of the Pharmacopoeia Monograph for this type of plant material.

A MODIFIED METHOD FOR STUDYING THE GLYCOXIDATION REACTION

The article considers a particular model of the glycation reaction, called glycoxidation and characterized by a significant involvement of oxidative reactions and the participation of transition metals. The enhancement of oxidative processes, which makes it possible to identify the reaction as glyoxidation, was realized by introducing copper (II) cations (CuSO 4 * 5H 2 O) into the reaction medium in a form accessible for interaction with the reaction participants. The main reagents in the glycoxidation reaction, in addition to CuSO 4 *5H 2 O are bovine serum albumin (1 g/l), glucose (0,5 M), HEPES buffer solution (24 g/l) dissolved in deionized water. The conditions have been selected under which the glycoxidation reaction linearly depends on the concentration of copper (II), which makes the cation activity a sensitive target when monitoring the reaction. The dependence of the reaction on the concentration of CuSO 4 * 5H 2 O under the presented experimental conditions has been confirmed experimentally and mathematically. An analytical range of concentrations of CuSO 4 *5H 2 O has been established, in which a linear dependence of AGE formation on concentration is observed. For the concentration of CuSO 4 *5H 2 O, which produces the greatest potentiating effect on the AGE formation (10 mg/l), the procedure was validated by the indices of internal laboratory reproducibility and convergence. The technique is of interest for investigation of the antiglycoxidative activity of novel compounds.

Linear discriminant analysis based on gas chromatographic measurements for geographical prediction of USA medical domestic cannabis

Fifty four domestically produced cannabis samples obtained from different USA states were quantitatively assayed by GC–FID to detect 22 active components: 15 terpenoids and 7 cannabinoids. The profiles of the selected compounds were used as inputs for samples grouping to their geographical origins and for building a geographical prediction model using Linear Discriminant Analysis. The proposed sample extraction and chromatographic separation was satisfactory to select 22 active ingredients with a wide analytical range between 5.0 and 1,000 µg/mL. Analysis of GC-profiles by Principle Component Analysis retained three significant variables for grouping job (Δ9-THC, CBN, and CBC) and the modest discrimination of samples based on their geographical origin was reported. PCA was able to separate many samples of Oregon and Vermont while a mixed classification was observed for the rest of samples. By using LDA as a supervised classification method, excellent separation of cannabis samples was attained leading to a classification of new samples not being included in the model. Using two principal components and LDA with GC–FID profiles correctly predict the geographical of 100% Washington cannabis, 86% of both Oregon and Vermont samples, and finally, 71% of Ohio samples.