scholarly journals Oxidation of Hydroxy- and Dihydroxybenzoic Acids Under the Udenfriend's Conditions. An HPLC Study

2018 ◽  
Vol 12 (1) ◽  
pp. 13-22 ◽  
Author(s):  
Mónika Kuzma ◽  
Nikoletta Kovács ◽  
Lilla Sziva ◽  
Gábor Maász ◽  
Péter Avar ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Biological Action ◽  
Dihydroxybenzoic Acid ◽  
Intermediate Precision ◽  
Hydroxylated Metabolites ◽  
Oxidative Reactions ◽  
Rp Hplc ◽  
Oxidized Products ◽  
Hplc Study

Background:Non-enzymatic hydroxylation of aromatic compounds to the respective phenolic derivatives is a possible metabolic pathway of xenobiotics. The formed metabolites can undergo consecutive oxidative reactions with free radicals to form potential toxic molecules.Objective:Development of HPLC methods to separate, identify and quantitate the main products formed from salicylic acid, 2,3-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid underin vitrohydroxylation conditions (Udenfriend's system).Method:An RP-HPLC-UV-Vis method was developed to separate salicylic acid and isomeric dihydroxybenzoic acids formed in the Udenfriend's system. Confirmation of structures of the oxidized products of salicylic acid, 2,3-dihydroxybenzoic acid and 2,5-dihydroxybenzoic acid was performed by HPLC-ESI-MS/MS method.Results:The HPLC-UV-Vis method was evaluated for a number of validation characteristics (selectivity, repeatability and intermediate precision, LOD, LOQ and calibration range). It was found that oxidation of salicylic acid resulted in the formation of 2,3- and 2,5-dihydroxybenzoic acids. Furthermore, the hydroxylated metabolites can be further metabolized under the Udenfriend’s conditions.Conclusion:The results give evidence for possible involvement of the oxidized metabolites of salicylic acid in the development of biological action of salicylates at the site of inflammation, where high hydroxyl radical level can be detected.

scholarly journals In vitro Dissolution Profile at Different Biological pH Conditions of Hydroxychloroquine Sulfate Tablets Is Available for the Treatment of COVID-19

2021 ◽  
Vol 7 ◽  
Author(s):  
Thirupathi Dongala ◽  
Naresh Kumar Katari ◽  
Santhosh Kumar Ettaboina ◽  
Anand Krishnan ◽  
Murtaza M. Tambuwala ◽  
...  
Keyword(s):  
Antimalarial Activity ◽  
Reversed Phase ◽  
In Vitro Dissolution ◽  
Dissolution Profile ◽  
Intermediate Precision ◽  
Rp Hplc ◽  
Relative Standard ◽  
Ph Conditions ◽  
Clinical Experiments

Hydroxychloroquine sulfate is one of an extensive series of 4-aminoquinolines with antimalarial activity. Moreover, it is used for the treatment of rheumatoid arthritis. Sometimes, hydroxychloroquine sulfate is beneficial for the treatment of autoimmune diseases. Based on recent clinical experiments, it is exploited for the treatment of COVID-19, coronavirus across the globe. The chromatogram separation was achieved by using Agilent, Zorbax C8, 250 mm × 4.6 mm i.d., column. The buffer consists of 0.01 M of 1-pentane sulfonic acid and 0.02% of orthophosphoric acid in purified water. Mixed buffer, acetonitrile, and methanol (800:100:100 v/v). The flow rate was 1.0 ml min−1, and injection volume was 10 μl. Detection was made at 254 nm by using a dual absorbance detector (DAD). The reversed-phase high-performance liquid chromatography (RP-HPLC) method has been developed and validated as per the current International Conference on Harmonization (ICH) guidelines to estimate hydroxychloroquine sulfate tablets. As part of method validation, specificity, linearity, precision, and recovery parameters were verified. The concentration and area relationships were linear (R2 > 0.999) over the concentration range of 25–300 μg ml−1 for hydroxychloroquine (HCQ). The relative standard deviations for precision and intermediate precision were <1.5%. The proposed RP-HPLC generic method was applied successfully to evaluate the in vitro dissolution profile with different pH conditions such as 0.1 N HCl, pH 4.5 acetate buffer, and pH 6.8 phosphate buffers as US-marketed reference products.

scholarly journals A Novel RP-HPLC-DAD Method Development for Anti-Malarial and COVID-19 Hydroxy Chloroquine Sulfate Tablets and Profiling of In-Vitro Dissolution in Multimedia.

2020 ◽  
Author(s):  
THIRUPATHI DONGALA ◽  
Santhosh Kumar Ettaboina ◽  
Naresh Kumar Katari
Keyword(s):  
Method Development ◽  
Antimalarial Activity ◽  
Hplc Method ◽  
In Vitro Dissolution ◽  
Dissolution Profile ◽  
Intermediate Precision ◽  
Rp Hplc ◽  
Relative Standard ◽  
Clinical Experiments

Abstract Hydroxychloroquine sulfate is one of a large series of 4-aminoquinolines with antimalarial activity. Moreover, it is used for the treatment of rheumatoid arthritis. Sometimes Hydroxychloroquine sulfate is very effective for the treatment of autoimmune diseases. Based on the recent clinical experiments it is exploiting for the treatment of COVID-19, corona virus across the globe. A Reverse phase RP-HPLC method have been developed and validated as per the current ICH guidelines for estimation of Hydroxychloroquine sulfate tablets. As part of method validation specificity, linearity, precision and recovery parameters were verified. The concentration and area relationships were linear (R2 > 0.999), over the concentration range of 25 to 300 µg mL-1 for HCQ. The relative standard deviations for precision and intermediate precision were less than 1.5%. The proposed RP-HPLC generic method was applied successfully for evaluation of invitro dissolution profile with different pH conditions like 0.1N HCl, pH 4.5 Acetate buffer and pH 6.8 Phosphate buffers of US marketed reference product.

scholarly journals A Novel RP-HPLC-DAD Method Development for Anti-Malarial and COVID-19 Hydroxy Chloroquine Sulfate Tablets and Profiling of In-Vitro Dissolution in Multimedia.

2020 ◽  
Author(s):  
THIRUPATHI DONGALA ◽  
Santhosh Kumar Ettaboina ◽  
Naresh Kumar Katari
Keyword(s):  
Method Development ◽  
Antimalarial Activity ◽  
Hplc Method ◽  
In Vitro Dissolution ◽  
Dissolution Profile ◽  
Intermediate Precision ◽  
Rp Hplc ◽  
Relative Standard ◽  
Clinical Experiments

Abstract Hydroxychloroquine sulfate is one of a large series of 4-aminoquinolines with antimalarial activity. Moreover, it is used for the treatment of rheumatoid arthritis. Sometimes Hydroxychloroquine sulfate is very effective for the treatment of autoimmune diseases. Based on the recent clinical experiments it is exploiting for the treatment of COVID-19, corona virus across the globe. A Reverse phase RP-HPLC method have been developed and validated as per the current ICH guidelines for estimation of Hydroxychloroquine sulfate tablets. As part of method validation specificity, linearity, precision and recovery parameters were verified. The concentration and area relationships were linear (R2 > 0.999), over the concentration range of 25 to 300 µg mL-1 for HCQ. The relative standard deviations for precision and intermediate precision were less than 1.5%. The proposed RP-HPLC generic method was applied successfully for evaluation of invitro dissolution profile with different pH conditions like 0.1N HCl, pH 4.5 Acetate buffer and pH 6.8 Phosphate buffers of US marketed reference product.

Influence of salicylic acid on organogenesis of in vitro plants Fragaria ananassa Duch.

2016 ◽  
Vol 48 (1) ◽  
pp. 26-33
Author(s):  
O.V. Subin ◽  
◽  
M.D. Melnychuk ◽  
A.F. Likhanov ◽  
O.L. Klyachenko ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Fragaria Ananassa ◽  
In Vitro Plants

In-vitro Kinetic Hydrolysis Study of Metronidazole Derivatives with Carvacrol and Eugenol Using Validated RP-HPLC Method

2020 ◽  
Vol 16 ◽  
Author(s):  
M. Alarjah
Keyword(s):  
Half Life ◽  
Hplc Method ◽  
Hydrolysis Rate ◽  
First Order ◽  
First Order Kinetics ◽  
Rp Hplc ◽  
Pharmacokinetic Properties ◽  
Pseudo First Order ◽  
Kinetic Hydrolysis

Background: Prodrugs principle is widely used to improve the pharmacological and pharmacokinetic properties of some active drugs. Much effort was made to develop metronidazole prodrugs to enhance antibacterial activity and or to improve pharmacokinetic properties of the molecule or to lower the adverse effects of metronidazole. Objective: In this work, the pharmacokinetic properties of some of monoterpenes and eugenol pro metronidazole molecules that were developed earlier were evaluated in-vitro. The kinetic hydrolysis rate constants and half-life time estimation of the new metronidazole derivatives were calculated using the validated RP-HPLC method. Method: Chromatographic analysis was done using Zorbbax Eclipse eXtra Dense Bonding (XDB)-C18 column of dimensions (250 mm, 4.6 mm, 5 μm), at ambient column temperature. The mobile phase was a mixture of sodium dihydrogen phosphate buffer of pH 4.5 and methanol in gradient elution, at 1ml/min flow rate. The method was fully validated according to the International Council for Harmonization (ICH) guidelines. The hydrolysis process carried out in an acidic buffer pH 1.2 and in an alkaline buffer pH 7.4 in a thermostatic bath at 37ºC. Results: The results followed pseudo-first-order kinetics. All metronidazole prodrugs were stable in the acidic pH, while they were hydrolysed in the alkaline buffer within a few hours (6-8 hr). The rate constant and half-life values were calculated, and their values were found to be 0.082- 0.117 hr-1 and 5.9- 8.5 hr., respectively. Conclusion: The developed method was accurate, sensitive, and selective for the prodrugs. For most of the prodrugs, the hydrolysis followed pseudo-first-order kinetics; the method might be utilised to conduct an in-vivo study for the metronidazole derivatives with monoterpenes and eugenol.

scholarly journals Improving the Biocontrol Potential of Bacterial Antagonists with Salicylic Acid against Brown Rot Disease and Impact on Nectarine Fruits Quality

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 209
Author(s):  
Nadia Lyousfi ◽  
Rachid Lahlali ◽  
Chaimaa Letrib ◽  
Zineb Belabess ◽  
Rachida Ouaabou ◽  
...  
Keyword(s):  
Salicylic Acid ◽  
Disease Severity ◽  
Mycelial Growth ◽  
Brown Rot ◽  
Antagonistic Bacteria ◽  
Biological Treatments ◽  
Rot Disease ◽  
The Impact

The main objective of this study was to evaluate the ability of both antagonistic bacteria Bacillus amyloliquefaciens (SF14) and Alcaligenes faecalis (ACBC1) used in combination with salicylic acid (SA) to effectively control brown rot disease caused by Monilinia fructigena. Four concentrations of salicylic acid (0.5%, 2%, 3.5%, and 5%) were tested under in vitro and in vivo conditions. Furthermore, the impact of biological treatments on nectarine fruit parameters’ quality, in particular, weight loss, titratable acidity, and soluble solids content, was evaluated. Regardless of the bacterium, the results indicated that all combined treatments displayed a strong inhibitory effect on the mycelial growth of M. fructigena and disease severity. Interestingly, all SA concentrations significantly improved the biocontrol activity of each antagonist. The mycelial growth inhibition rate ranged from 9.79% to 88.02% with the highest reduction rate recorded for bacterial antagonists in combination with SA at both concentrations of 0.5% and 3.5%. The in vivo results confirmed the in vitro results with a disease severity varying from 0.00% to 51.91%. A significant biocontrol improvement was obtained with both antagonistic bacteria when used in combination with SA at concentrations of 0.5% and 2%. The lowest disease severity observed with ACBC1 compared with SF14 is likely due to a rapid adaptation and increase of antagonistic bacteria population in wounded sites. The impact of all biological treatments revealed moderate significant changes in the fruit quality parameters with weight loss for several treatments. These results suggest that the improved disease control of both antagonistic bacteria was more likely directly linked to both the inhibitory effects of SA on pathogen growth and induced fruit resistance.

scholarly journals Comparison of the Cerumenolytic Activities of New and Currently Used Agents

2021 ◽  
pp. 014556132098606
Author(s):  
Nguyen Quynh Anh ◽  
Pawin Numthavaj ◽  
Thongchai Bhongmakapat
Keyword(s):  
Salicylic Acid ◽  
Sodium Bicarbonate ◽  
Potassium Hydroxide ◽  
Glycolic Acid ◽  
Statistical Significance ◽  
In Vitro Study ◽  
Distilled Water ◽  
Moderate Amount ◽  
All Solutions

Objectives: This study compared the cerumen dissolution activities of 7.5% sodium bicarbonate, 5% potassium hydroxide, 10% lactic acid, 3% salicylic acid, 10% glycolic acid, and distilled water. Methods: An in vitro study was conducted with 36 cerumen samples. The cerumenolytic activities of the 6 agents were assessed by recording the degree of cerumen disintegration using digital photography at 15 minutes, 30 minutes, 1 hour, 2 hours, and 12 hours. The undissolved cerumen that remained after 12 hours was removed from the solutions and weighed after drying. Results: Potassium hydroxide showed the fastest cerumenolytic activity, dissolving a moderate amount of cerumen at 30 minutes, while glycolic acid and salicylic acid caused no visible changes in the cerumen samples. Samples treated with potassium hydroxide and sodium bicarbonate exhibited higher degrees of disintegration compared to samples treated with distilled water (odds ratio and 95% CI: 273.237 [0.203-367 470.4] and 1.129 [0.002-850.341], respectively). The greatest reduction in cerumen weight was associated with the use of sodium bicarbonate; however, this result did not reach statistical significance. Conclusions: Among the solutions tested, 5% potassium hydroxide showed the fastest dissolution activity, yielding moderate disintegration within only 30 minutes. In terms of residual cerumen weight within 12 hours, all solutions exhibited equivalent effectiveness in the disintegration of cerumen.

scholarly journals Isoprostanes in Veterinary Medicine: Beyond a Biomarker

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 145
Author(s):  
Ashley K. Putman ◽  
G. Andres Contreras ◽  
Lorraine M. Sordillo
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Veterinary Medicine ◽  
Biological Fluids ◽  
Biological Action ◽  
Clinical Applications ◽  
Animal Medicine ◽  
Inflammatory Processes ◽  
Oxidized Products ◽  
Biomarkers Of Oxidative Stress

Oxidative stress has been associated with many pathologies, in both human and animal medicine. Damage to tissue components such as lipids is a defining feature of oxidative stress and can lead to the generation of many oxidized products, including isoprostanes (IsoP). First recognized in the early 1990s, IsoP are formed in numerous biological fluids and tissues, chemically stable, and easily measured by noninvasive means. Additionally, IsoP are highly specific indicators of lipid peroxidation and thereby are regarded as excellent biomarkers of oxidative stress. Although there have been many advancements in the detection and use of IsoP as a biomarker, there is still a paucity of knowledge regarding the biological activity of these molecules and their potential roles in pathology of oxidative stress. Furthermore, the use of IsoP has been limited in veterinary species thus far and represents an avenue of opportunity for clinical applications in veterinary practice. Examples of clinical applications of IsoP in veterinary medicine include use as a novel biomarker to guide treatment recommendations or as a target to mitigate inflammatory processes. This review will discuss the history, biosynthesis, measurement, use as a biomarker, and biological action of IsoP, particularly in the context of veterinary medicine.

scholarly journals A non-human primate in vitro functional assay for the early evaluation of TB vaccine candidates

npj Vaccines ◽  
2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Rachel Tanner ◽  
Andrew D. White ◽  
Charelle Boot ◽  
Claudia C. Sombroek ◽  
Matthew K. O’Shea ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Mononuclear Cells ◽  
Functional Assay ◽  
Intermediate Precision ◽  
Peripheral Blood Mononuclear ◽  
Growth Inhibition Assay ◽  
Early Evaluation ◽  
Human Primate

AbstractWe present a non-human primate mycobacterial growth inhibition assay (MGIA) using in vitro blood or cell co-culture with the aim of refining and expediting early tuberculosis vaccine testing. We have taken steps to optimise the assay using cryopreserved peripheral blood mononuclear cells, transfer it to end-user institutes, and assess technical and biological validity. Increasing cell concentration or mycobacterial input and co-culturing in static 48-well plates compared with rotating tubes improved intra-assay repeatability and sensitivity. Standardisation and harmonisation efforts resulted in high consistency agreements, with repeatability and intermediate precision <10% coefficient of variation (CV) and inter-site reproducibility <20% CV; although some systematic differences were observed. As proof-of-concept, we demonstrated ability to detect a BCG vaccine-induced improvement in growth inhibition in macaque samples, and a correlation between MGIA outcome and measures of protection from in vivo disease development following challenge with either intradermal BCG or aerosol/endobronchial Mycobacterium tuberculosis (M.tb) at a group and individual animal level.

scholarly journals The effect of chelating agents on iron mobilization in Chang cell cultures

Blood ◽  
1976 ◽  
Vol 48 (6) ◽  
pp. 923-929 ◽  
Author(s):  
GP White ◽  
A Jacobs ◽  
RW Grady ◽  
A Cerami
Keyword(s):  
Cell Cultures ◽  
Chelating Agents ◽  
Transferrin Saturation ◽  
Molar Ratio ◽  
Iron Release ◽  
Dihydroxybenzoic Acid ◽  
Equal Degree ◽  
Therapeutic Value ◽  
Chang Cell

Abstract The investigation of chelating agents with potential therapeutic value in patients with transfusional iron overload has been facilitated by the use of Chang cell cultures. These cells have been incubated with [59Fe]transferrin for 22 hr, following which most of the intracellular radioiron is found in the cytosol, distributed between a ferritin and a nonferritin form. Iron release from the cells depends on transferrin saturation in the medium, but when transferrin is 100% saturated, which normally does not allow iron release, desferrioxamine, 2,3- dihydroxybenzoic acid, rhodotorulic acid, cholythydroxamic acid, and tropolone all promote the mobilization of ferritin iron and its release from cells. They are effective to an approximately equal degree. The incubation of [59Fe]transferrin with tropolone in vitro at a molar ratio of 1:500 results in the transfer of most of the labeled iron to the chelator, reflecting the exceptionally high binding constant of this compound. How far these phenomena relate to therapeutic potentially remains to be seen.

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