scholarly journals Determination of pKa and Degradation Products of the Mutated BRAF Inhibitor Vemurafenib and UPLC Assay in Human Urine

2020 ◽  
pp. 18-27
Author(s):  
Senem Şanli ◽  
Ayşe Özdemir ◽  
Gülşen Güven ◽  
Süleyman Gökçe
Keyword(s):  
Oxidative Stress ◽  
Human Urine ◽  
Mobile Phase ◽  
Degradation Products ◽  
Braf Inhibitor ◽  
Retention Factor ◽  
Stress Conditions ◽  
Pka Value ◽  
And Oxidative Stress

In this study, the pKa value of vemurafenib was determined by the dependence of the retention factor on the pH of the mobile phase. The change of pKa in the different acetonitrile fraction ranging between 57.5 and 62.5% (v/v) was studied by using an LC-UV method. Additionally, a simple, reliable, and rapid UPLC method has been developed for the determination of vemurafenib in human urine. Efavirenz was used as an internal standart. For vemurafenib and efavirenz, selectivity factors were found as 1.204. The asymmetry and capacity factors were obtained as 1.100 and 7.532 for vemurafenib. Vemurafenib was exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were detected by LC/MS/MS method.

RP-HPLC METHOD FOR DETERMINATION OF TOLPERISONE HYDROCHLORIDE IN TABLET FORMULATION

INDIAN DRUGS ◽  
2016 ◽  
Vol 53 (10) ◽  
pp. 48-53
Author(s):  
S. P Padmane ◽  
◽  
A. A Thakur ◽  
R. N. Alaspure ◽  
M. R. Tajne
Keyword(s):  
Oxidative Stress ◽  
Degradation Products ◽  
Hplc Method ◽  
Tablet Formulation ◽  
Stress Conditions ◽  
Stability Indicating ◽  
Rp Hplc ◽  
Effluent Flow Rate ◽  
And Oxidative Stress

The study describes a validated stability indicating reverse-phase HPLC method for the estimation of tolperisone in bulk and in tablet formulation. The proposed RP-HPLC method utilizes a Hypersil C18 column (250 × 4.6 mm, 5 μm), optimum mobile phase consisted of methanol: acetonitrile: water (containing triethylamine 1% V/V) in the ratio of (85:10:5 V/V/V), effluent flow rate was kept at 1.0 mL/min and UV detection wavelength 250 nm. Tolperisone was exposed to various hydrolytic, thermal, photolytic and oxidative stress conditions, and the stressed samples were analysed by proposed method. The drug showed degradation under alkali and neutral hydrolysis and oxidative stress conditions. The degradation products were well resolved from the drug and demonstrated that the method is specific stability indicating for assay of tolperisone in presence of degradation products. The developed method was validated for linearity, accuracy, precision, robustness, ruggedness and specificity.

scholarly journals Selective Determination of Diazinon and Chlorpyrifos in the Presence of Their Degradation Products: Application to Environmental Samples

2018 ◽  
Vol 101 (4) ◽  
pp. 1191-1197 ◽  
Author(s):  
Mamdouh R Rezk ◽  
Abd El-Aziz B Abd El-Aleem ◽  
Shaban M Khalile ◽  
Omneya K El-Naggar
Keyword(s):  
Flow Rate ◽  
Environmental Samples ◽  
Mobile Phase ◽  
Degradation Products ◽  
Hplc Method ◽  
Stress Conditions ◽  
Uv Detection ◽  
Selective Determination ◽  
International Conference

Abstract An accurate, sensitive, and selective HPLC method was developed and validated for the determination of diazinon and chlorpyrifos. These pesticides were subjected to different stress conditions, such as acidic, alkaline, oxidative, thermal, and photolytic hydrolysis. The proposed method used a C18 Eclipse Plus column (100 × 4.6 mm, 3.5 µm) and a mobile phase consisting of acetonitrile–water (70 + 30, v/v) in an isocratic separation mode. The flow rate was 1.5 mL/min, with UV detection at 247 and 230 nm for diazinon and chlorpyrifos, respectively. The proposed method was linear over the range of 0.40–50.00 µg/mL for diazinon and 0.40–40.00 µg/mL for chlorpyrifos. The proposed method was validated per International Conference on Harmonization guidelines and subsequently applied for the successful determination of the studied pesticides in bulk form in their commercial samples in the presence of their degradation products. The developed method was used for the determination of the residues of these pesticides in lavender and rosemary leaves that were pretreated with the recommended doses of these pesticides.

A Validated Stability-Indicating RP-LC Method for the Simultaneous Determination of Amlodipine and Perindopril in Tablet Dosage Form and Their Stress Degradation Behavior Under ICH-Recommended Stress Conditions

2013 ◽  
Vol 96 (4) ◽  
pp. 751-757 ◽  
Author(s):  
Mehmet Gumustas ◽  
Sibel A Ozkan
Keyword(s):  
Simultaneous Determination ◽  
Mobile Phase ◽  
Dosage Form ◽  
Degradation Products ◽  
Stress Conditions ◽  
Assay Method ◽  
Pharmaceutical Dosage Form ◽  
Stability Indicating ◽  
Tablet Dosage

Abstract A stability-indicating RP-LC assay method was developed for the simultaneous determination of the cardiovascular drugs amlodipine and perindopril in the presence of degradation products generated from forced decomposition studies. The developed method is applicable for the determination of related substances in bulk drugs and simultaneous assay in a tablet pharmaceutical dosage form. Separation of the drugs and their degradation products was obtained using an RP Waters Spherisorb ODS1 column (250 × 4.6 mm id, 5 μm particle size) with the mobile phase acetonitrile–water (30 + 70, v/v) containing 15 mM phosphoric acid. The pH of the mobile phase was adjusted to 5.0. A flow rate of 1.2 mL/min was used for the separations, with detection at 215 nm. The chromatographic separation was performed at a column temperature of 45°C. Atenolol was chosen as the internal standard. Amlodipine and perindopril were exposed to thermal, photolytic, hydrolytic, and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Degradation studies showed that both compounds were degraded under these stress conditions. The method was found to be stability-indicating and can be used for the routine analysis of amlodipine and perindopril in the studied combined tablet dosage form.

O XVII B.2 Determination of endogenous DNA damage, oxidated DNA bases and oxidative stress in primary human colon cells and modulation by plant ingredients

1997 ◽  
Vol 379 (1) ◽  
pp. S171
Author(s):  
Beatrice L. Pool-Zobel ◽  
Salomon L. Abrahamse ◽  
Daniela Oberreuther ◽  
Sylvia Treptow-van Lishaut ◽  
Gerhard Rechkemmer
Keyword(s):  
Oxidative Stress ◽  
Dna Damage ◽  
Human Colon ◽  
Dna Bases ◽  
Colon Cells ◽  
And Oxidative Stress

Development and Validation of HPLC Determination of related Substances in A Novel Anticonvulsant agent Epimidin

2021 ◽  
pp. 3223-3231
Author(s):  
Hanna I. Severina ◽  
Svitlana M. Gubar ◽  
Ivan V. Bezruk ◽  
Anna S. Materiienko ◽  
Liudas Ivanauskas ◽  
...  
Keyword(s):  
Mobile Phase ◽  
Phosphate Buffer Solution ◽  
Anticonvulsant Drug ◽  
Strong Acid ◽  
Gradient Elution ◽  
Stress Conditions ◽  
Drug Candidate ◽  
Buffer Solution ◽  
Related Substances

1-(4-methoxyphenyl)-5-[2-[4-(4-methoxyphenyl)piperazin-1-yl]-2-oxo-ethyl]pyrazolo[3,4-d]pyrimidin-4-one has been reported as a promising new anticonvulsant drug candidate with a code name “Epimidin”. A new HPLC method for the related substances determination of potential active pharmaceutical ingredient has been developed and validated. The method uses ACE C18 column (250x4.6mm, 5µm) and gradient elution. Mobile phase consisted of a mixture of methanol R (mobile phase A) and phosphate buffer solution with triethanolamine, adjusted to pH 7.0 (mobile phase B). During the analysis, the ratio of mobile phases was changing according to a gradient mode at a flow rate of 1ml/min. The DAD detection was set at 240nm. The method was validated according to the ICH guidelines and requirements of State Pharmacopoeia of Ukraine. Drug substance was thoroughly explored for stability assessments under various stress conditions such as high temperature, as well as the influence of strong acid and base and oxidizing agents. The obtained solutions were analyzed by HPLC and LC/MS. It has been shown that the substance Epimidin was not resistant to the action of peroxide, alkali and acid decomposition – the mentioned stress conditions lead to the formation of unidentified impurities.

scholarly journals Photostability study of amlodipine besylate tablets packed in primary packaging

2021 ◽  
Vol 10 (1) ◽  
pp. 20-28
Author(s):  
Ivana Savić-Gajić ◽  
Ivan Savić ◽  
Predrag Sibinović ◽  
Valentina Marinković
Keyword(s):  
Mobile Phase ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Hplc Method ◽  
Coefficient Of Determination ◽  
Amlodipine Besylate ◽  
Limit Of Quantification ◽  
First Order Kinetics ◽  
The Given

In this study, the modified stability-indicating RP-HPLC method was validated for quantitative analysis of amlodipine besylate in the presence of its impurity D (3-ethyl 5-methyl 2-[(2-aminoethoxy)methyl]-4-(2-chlorophenyl)-6-methylpyridine-3,5-dicarboxylate). The method was applied for the determination of an analyte in the tablets and irradiated samples packed in the primary packaging (Alu/PVC/PVDC blister packaging). The efficient chromatographic separation was achieved using a ZORBAX Eclipse XDB-C18 column (4.6×250 mm, 5 mm) with isocratic elution of mobile phase which consisted of acetonitrile:methanol:triethylamine solution (15:35:50, v/v/v) (pH 3.0). The flow rate of the mobile phase was 1 mL min-1, while the detection of amlodipine besylate was carried out at 273 nm. Amlodipine besylate and its impurity D were identified at the retention times of 16.529 min and 2.575 min, respectively. The linearity of the method with the coefficient of determination of 0.999 was confirmed in the concentration range of 10 - 75 µg mL-1 for amlodipine besylate. The limit of detection was 0.2 µg mL-1, while the limit of quantification was 0.66 µg mL-1. After UV and Vis radiation of the tablets packed in the primary packaging, the content of amlodipine besylate was reduced by 22.38% and 19.89%, respectively. The presence of new degradation products was not detected under the given chromatographic conditions. The photodegradation of amlodipine besylate followed pseudo-first-order kinetics. Based on the half-life of amlodipine besylate (38.4 days for UV radiation and 43.3 days for Vis radiation), it was concluded that amlodipine besylate in the tablets has satisfactory photostability after its packing in the Alu/PVC/PVDC blister packaging.

scholarly journals Identification of novel small RNAs in Burkholderia cenocepacia KC-01 expressed under iron limitation and oxidative stress conditions

Microbiology ◽  
2017 ◽  
Vol 163 (12) ◽  
pp. 1924-1936 ◽  
Author(s):  
Suparna Ghosh ◽  
Chetna Dureja ◽  
Indu Khatri ◽  
Srikrishna Subramanian ◽  
Saumya Raychaudhuri ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Small Rnas ◽  
Stress Conditions ◽  
Iron Limitation ◽  
Burkholderia Cenocepacia ◽  
And Oxidative Stress

scholarly journals Intra-Vitreal Administration of Microvesicles Derived from Human Adipose-Derived Multipotent Stromal Cells Improves Retinal Functionality in Dogs with Retinal Degeneration

2019 ◽  
Vol 8 (4) ◽  
pp. 510
Author(s):  
Anna Cislo-Pakuluk ◽  
Agnieszka Smieszek ◽  
Natalia Kucharczyk ◽  
Peter G.C. Bedford ◽  
Krzysztof Marycz
Keyword(s):  
Oxidative Stress ◽  
Retinal Degeneration ◽  
Stromal Cells ◽  
Clinical Studies ◽  
Stress Conditions ◽  
In Vitro Assays ◽  
Multipotent Stromal Cells ◽  
Mitochondrial Potential ◽  
And Oxidative Stress

This study was designed to determine the influence of microvesicles (MVs) derived from multipotent stromal cells isolated from human adipose tissue (hASCs) on retinal functionality in dogs with various types of retinal degeneration. The biological properties of hASC-MVs were first determined using an in vitro model of retinal Muller-like cells (CaMLCs). The in vitro assays included analysis of hASC-MVs influence on cell viability and metabolism. Brain-derived neurotrophic factor (BDNF) expression was also determined. Evaluation of the hASC-MVs was performed under normal and oxidative stress conditions. Preliminary clinical studies were performed on ten dogs with retinal degeneration. The clinical studies included behavioral tests, fundoscopy and electroretinography before and after hASC-MVs intra-vitreal injection. The in vitro study showed that CaMLCs treated with hASC-MVs were characterized by improved viability and mitochondrial potential, both under normal and oxidative stress conditions. Additionally, hASC-MVs under oxidative stress conditions reduced the number of senescence-associated markers, correlating with the increased expression of BDNF. The preliminary clinical study showed that the intra-vitreal administration of hASC-MVs significantly improved the dogs’ general behavior and tracking ability. Furthermore, fundoscopy demonstrated that the retinal blood vessels appeared to be less attenuated, and electroretinography using HMsERG demonstrated an increase in a- and b-wave amplitude after treatment. These results shed promising light on the application of cell-free therapies in veterinary medicine for retinal degenerative disorders treatment.

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