High-performance Liquid Chromatography Research Articles

Bioguided Fractionation of Phyllanthus spp.: Unveiling Anticancer Potential through Metabolomic Correlation and ADMETox Insights.

Cancer remains a significant global health concern, with mortality rates steadily rising and prompting an urgent search for effective treatments. This study focuses on the medicinal properties of plants from the Phyllanthus genus, specifically Phyllanthus amarus and Phyllanthus niruri, which have shown promise in traditional medicine. Through bioguided fractionation using preparative high-performance liquid chromatography (HPLC), bioactive compounds were isolated and identified using ultra-performance liquid chromatography coupled to time-of-flight mass spectrometry (UHPLC-QTOF-MSE) and nuclear magnetic resonance (NMR) spectroscopy. Chemometric analyses such as principal component analysis (PCA) aided in understanding metabolite distribution. Biological assays demonstrated cytotoxic activities of specific fractions against cancer cell lines, notably the PhyN 4n fraction from P. niruri, which induced S-phase cell cycle arrest and apoptosis in HL60 cells. These findings underscore the anticancer potential of Phyllanthus species and lay the groundwork for future drug development efforts. The study's integration of advanced analytical techniques, chemometrics, and biological assays provides valuable insights for harnessing natural products in the fight against cancer.

Centella asiatica (L.) Urb. and Hydrocotyle umbellata L. identification and quality assessment: A methodology comparison.

Centella is an important genus in the Apiaceae family. It includes Centella asiatica, which has significant edible and medicinal values. However, this species is easily confused due to its similar morphological traits to Hydrocotyle umbellata, hindering its utilization in the consumer and pharmacological industries. The study aims to differentiate these two closely related plant species using reliable methods of confirming the authenticity of natural herbal medicines. Our work mainly focuses on the basic morphological characteristics, chemical markers, genetic fingerprints, and their biological responses. The plants can be clearly differentiated using their leaf shapes, stipules, petioles, inflorescences, and fruit structures. Although the phytochemical compositions of the C. asiatica extract were similar to that of H. umbellata which included flavonoids, tannins, and saponins important to the plant's ability to reduce inflammation and promote healing of wounds, the H. umbellata extract showed significantly higher toxicity than that of C. asiatica. High-performance liquid chromatography analysis was used to identify chemical fingerprints. The result revealed that C. asiatica had major triterpene glycoside constituents including asiaticoside, asiatic acid, madecassoside, and madecassic acid, which have a wide range of medicinal values. In contrast, triterpenoid saponins were not identified in H. umbellata. Furthermore, using SCoT1-6 primers was possible to effectively and sufficiently created a dendrogram which successfully identified the closeness of the plants and confirmed the differences between the two plant species. Therefore, differentiation can be achieved through the combination of morphometrics, molecular bioactivity, and chemical analysis.

Identification and Molecular Docking Analysis of Angiotensin-Converting Enzyme Inhibitors from Finger Millet (Eleusine coracana).

Hypertension remains a significant global health concern, contributing significantly to cardiovascular diseases and mortality rates. The inhibition of angiotensin-converting enzyme (ACE) plays a crucial role in alleviating high blood pressure. We investigated the potential of finger millets (Eleusine coracana) as a natural remedy for hypertension by isolating and characterizing its ACE-inhibitory compound. First, we evaluated the ACE-inhibitory activity of the finger millet ethanol extract and subsequently proceeded with solvent fractionation. Among the solvent fractions, the ethyl acetate fraction exhibited the highest ACE inhibitory activity and was further fractionated. Using preparative high-performance liquid chromatography, the ethyl acetate fraction was separated into four subfractions, with fraction 2 (F2) exhibiting the highest ACE inhibitory activity. Subsequent 1H-nuclear magnetic resonance (NMR) and 13C-NMR analyses confirmed that the isolated compound from F2 was catechin. Furthermore, molecular docking studies indicated that catechin has the potential to act as an ACE inhibitor. These findings suggest that finger millets, particularly as a source of catechin, have the potential to be used as a natural antihypertensive.

A new sensitive layer based on clcinated Zn/Ti-MOF/magnetic molecularly imprinted polypyrrole: Application to preconcentration and electrochemical determination of perfluorooctane sulfonic acid by magnetic carbon paste electrode

In this research, a new approach based on magnetic electrodes has been developed for the determination of per-fluorooctane sulfonic acid (PSOF). Zinc and Titanium-based Metal-organic framework (MOF) was synthesized and used with polypyrrole as a conductive polymer for preparation of the absorbent to achieve the best performance for electrochemical application. The response of the electrode for determination of the PFOS was affected and optimized by different factors such as buffer solution, pH of the solution, amount of absorbent, extraction time of absorbent, accumulation time, as well as the Square Wave Voltammetry (SWV) instrumental parameters including voltage step, pulse amplitude, frequency and resting time. In the optimum condition, the response of the Zn/Ti/C-MOF-magnetic molecular imprinting polymer/carbon paste electrode (MOFMMIP/CPE) has increased logarithmically by increasing the concentration in the range of 0.002–165 μM by the limit of detection (LOD) of 0.7 nM. The obtained percentage of Recovery (96.00–104.14 %), Bias (–4.00 - 4.14 %) and Relative Standard Deviation (RSD) (1.89–3.74 %) for determination of the PFOS in real and spiked tap water, river water and well water samples demonstrates that the proposed method has an acceptable precision. The comparison between the gained data by the presented method and High-performance liquid chromatography (HPLC) showed that the presented method has high accuracy.

Novel Alaninamide Derivatives with Drug-like Potential for Development as Antiseizure and Antinociceptive Therapies─In Vitro and In Vivo Characterization.

In the present study, a series of original alaninamide derivatives have been designed applying a combinatorial chemistry approach, synthesized, and characterized in the in vivo and in vitro assays. The obtained molecules showed potent and broad-spectrum activity in basic seizure models, namely, the maximal electroshock (MES) test, the 6 Hz (32 mA) seizure model, and notably, the 6 Hz (44 mA) model of pharmacoresistant seizures. Most potent compounds 26 and 28 displayed the following pharmacological values: ED50 = 64.3 mg/kg (MES), ED50 = 15.6 mg/kg (6 Hz, 32 mA), ED50 = 29.9 mg/kg (6 Hz, 44 mA), and ED50 = 34.9 mg/kg (MES), ED50 = 12.1 mg/kg (6 Hz, 32 mA), ED50 = 29.5 mg/kg (6 Hz, 44 mA), respectively. Additionally, 26 and 28 were effective in the ivPTZ seizure threshold test and had no influence on the grip strength. Moreover, lead compound 28 was tested in the PTZ-induced kindling model, and then, its influence on glutamate and GABA levels in the hippocampus and cortex was evaluated by the high-performance liquid chromatography (HPLC) method. In addition, 28 revealed potent efficacy in formalin-induced tonic pain, capsaicin-induced pain, and oxaliplatin- and streptozotocin-induced peripheral neuropathy. Pharmacokinetic studies and in vitro ADME-Tox data proved favorable drug-like properties of 28. The patch-clamp recordings in rat cortical neurons showed that 28 at a concentration of 10 μM significantly inhibited fast sodium currents. Therefore, 28 seems to be an interesting candidate for future preclinical development in epilepsy and pain indications.

A Validated Chiral Chromatography Method for Enantiomeric Separation of Pomalidomide in Human Plasma.

In the present work, new chiral stationary phase high-performance liquid chromatography (CSP-HPLC) method was established and validated for the quantification of pomalidomide (PMD) enantiomers in human plasma. The chromatographic enantiomeric separation was achieved on a Daicel-CSP, Chiralpack IA 4.6 × 250mm, 5μm; because of its advantages of high degree of retention, high resolution capacity, better reproducibility, ability to produce lower back pressure and low degree of tailing. The mobile phase was maintained as methanol: glacial acetic acid (499.50ml:50μL). Ultraviolet wavelength for detection was 220nm. PMD enantiomer-I and enantiomer-II were separated at 8.83 and 15.34min, respectively. Limit of detection and limit of quantification for each enantiomer and the calibration curve of standard PMD was linear in range between 10-5,000ngmL-1. The method was validated according to The International Council for Harmonisation of Technical Requirements of Pharmaceuticals for Human Use (ICH(Q2R1)) specific guidelines. We found no interference peak with PMD chromatogram obtained. This is a simple, reliable and specific method for detection and quantification of enantiomer of PMD in human plasma sample.

Qualitative and Quantitative Analysis of Chemical Components in Yinhua Pinggan Granule with High-Performance Liquid Chromatography Coupled with Q-Exactive Mass Spectrometry

Qualitative and Quantitative Analysis of Chemical Components in Yinhua Pinggan Granule with High-Performance Liquid Chromatography Coupled with Q-Exactive Mass Spectrometry

High-Performance Liquid Chromatographic Quantification of the Plant Hormone Abscisic Acid at ppb Levels in Plant Samples after a Single Immunoaffinity Column Cleanup.

High-performance liquid chromatography with ultraviolet detection (HPLC-UV) is a common analysis technique due to its high versatility and simple operation. In the present study, HPLC-UV detection was integrated with immunoaffinity cleanup (IAC) of the sample extracts. The matrix effect was greatly reduced, and the limit of detection was as low as 1 ng/g of free abscisic acid (ABA) in fresh plant tissues. A monoclonal antibody 3F1 (mAb 3F1) was developed to specifically recognize free ABA but not ABA analogues. The mAb 3F1-immobilized immunoaffinity column exhibited a capacity of 850 ng/mL and an elution efficiency of 88.8-105% for standards. The extraction recoveries of the column for ABA ranged from 80.4 to 108.9%. ABA content was detected in various plant samples with IAC-HPLC-UV. The results were verified with ultraperformance liquid chromatography-electrospray tandem mass spectrometry. IAC-HPLC-UV can be a sensitive and cost-efficient method for plant hormone analysis.

Association between serum vitamin A and body mass index in adolescents from NHANES 1999 to 2006

Vitamin A plays a pivotal role in health, particularly in regulating fat metabolism. Despite its significance, research into the direct relationship between vitamin A levels and obesity, especially among adolescents, is sparse. This study aims to explore this association within the adolescent population in the United States. This cross-sectional study analyzed the National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2006, with 8218 participants. The levels of vitamin A in the serum were determined based on utilizing high-performance liquid chromatography with photodiode array detection. The relationship between serum vitamin A concentrations and body mass index (BMI) was evaluated using weighted multiple linear regression models, incorporating subgroup analyses by sex and race/ethnicity to provide nuanced insights. A positive correlation was observed between serum vitamin A levels and BMI, with BMI increasing progressively across vitamin A quartiles (P < 0.001). Using the lowest quartile of serum vitamin A as a reference, the BMI of the highest quartile of serum vitamin A was 1.236 times higher (95% CI 0.888, 1.585). Subgroup analyses revealed that this positive association persisted across different genders and racial/ethnic groups (P < 0.001). Notably, smooth curve fitting and saturation threshold analysis unveiled an inverted U-shaped relationship between serum vitamin A and BMI among female adolescents, non-Hispanic Whites, Mexican Americans, and other races/ethnicities groups. Our study substantiates the association between serum vitamin A levels and the risk of obesity/overweight status in adolescents. The findings suggest the potential serum vitamin A is an early biomarker for identifying obesity risk, although further studies are needed to determine to clarify its role as a contributing factor to obesity. This study contributes to the understanding of nutritional influences on adolescent obesity, highlighting the need for targeted interventions based on serum biomarkers.

Evaluation of dental pulp stem cells response to flowable nano-hybrid dental composites: A comparative analysis.

Flowable resin composites (FRC) are tooth-colored restorative materials that contain a lower filler particle content, and lower viscosity than their bulk counterparts, making them useful for specific clinical applications. Yet, their chemical makeup may impact the cellular population of the tooth pulp. This in-vitro study assessed the cytocompatibility and odontogenic differentiation capacity of dental pulp stem cells (DPSCs) in response to two recent FRC material extracts. Extracts of the FRC Aura easyflow (AEF) and Polofil NHT Flow (PNF) were applied to DPSCs isolated from extracted human teeth. Cell viability of DPSCs was assessed using MTT assay on days 1, 3 and 7. Cell migration was assessed using the wound healing assay. DPSCs' capacity for osteo/odontogenic differentiation was assessed by measuring the degree of mineralization by Alizarin Red S staining, alkaline phosphatase enzyme (ALP) activity, and monitoring the expression of osteoprotegerin (OPG), RUNX Family Transcription Factor 2 (RUNX2), and the odontogenic marker dentin sialophosphoprotein (DSPP) by RT-PCR. Monomer release from the FRC was also assessed by High-performance liquid chromatography analysis (HPLC). DPSCs exposed to PNF extracts showed significantly higher cell viability, faster wound closure, and superior odontogenic differentiation. This was apparent through Alizarin Red staining of calcified nodules, elevated alkaline phosphatase activity, and increased expression of osteo/odontogenic markers. Moreover, HPLC analysis revealed a higher release of TEDGMA, UDMA, and BISGMA from AEF. PNF showed better cytocompatibility and enhancement of odontogenic differentiation than AEF.

Miniaturized matrix solid-phase dispersion assisted by deep eutectic solvent for acrylamide determination in bread samples.

Acrylamide determination is important to state its quantity in baked food preventing any potential carcinogenic effects. Matrix solid-phase dispersion (MSPD) extraction is an extraction procedure based on a homogenization phase between a solid sample and a solid dispersing material to break sample increasing analyte extraction yield, often used for acrylamide determination. The addition of a green deep eutectic solvent (DES) during the MSPD homogenization phase improves the analyte extraction, giving the possibility to reduce the amount of organic solvent used. In this work, a miniaturized MSPD extraction assisted by a DES was developed to determine acrylamide in bread, using high-performance liquid chromatography coupled with mass spectrometry detection. The optimized procedure provides 1:1 (w/w) matrix-to-dispersing material ratio, 2mL of methanol as extraction solvent, and 50 μL of choline chloride-glycerol DES added during the homogenization phase. Method validation ensured good results with minimum recoveries of 90%, high precision with a maximum intra-day error of 4%, and inter-day error of 6%. Limit of detection and limit of quantification resulted to be 16μg/kg and 35μg/kg, respectively. This miniaturized extraction procedure represents a good alternative to those reported in the literature, guaranteeing great performance and respecting green chemistry principles.

Innovative Solid-Phase Extraction Strategies for Improving the Advanced Chromatographic Determination of Drugs in Challenging Biological Samples

In the past few decades, considerable scientific strides have been made in the subject of drug analysis in human biological samples. However, the risk caused by incorrect drug plasma levels in patients still remains an important concern. This review paper attempts to investigate the advances made over the last ten years in common sample preparation techniques (SPT) for biological samples based on solid sorbents, including solid-phase extraction (SPE) and solid-phase micro-extraction (SPME), and in particular in the field of molecularly imprinted polymers (MIPs), including non-stimuli-responsive and stimuli-responsive adsorbents. This class of materials is known as ‘smart adsorbents’, exhibiting tailored responses to various stimuli such as magnetic fields, pH, temperature, and light. Details are provided on how these advanced SPT are changing the landscape of modern drug analysis in their coupling with liquid chromatography-mass spectrometry (LC-MS) analytical techniques, a general term that includes high-performance liquid chromatography (HPLC) and ultra-high performance liquid chromatography (UHPLC), as well as any variation of MS, such as tandem (MS/MS), multiple-stage (MSn), and high-resolution (HRMS) mass spectrometry. Some notes are also provided on coupling with less-performing techniques, such as high-performance liquid chromatography with ultraviolet (HPLC-UV) and diode array detection (HPLC-DAD) detection. Finally, we provide a general review of the difficulties and benefits of the proposed approaches and the future prospects of this research area.

The Effect of Hyperbaric Storage on the Nutritional Value and Retention of Certain Bioactive Proteins in Human Milk

Human milk (HM) contains the essential macronutrients and bioactive compounds necessary for the normal growth and development of newborns. The milk collected by human milk banks is stored frozen and pasteurized, reducing its nutritional and biological value. The purpose of this study was to determine the effect of hyperbaric storage at subzero temperatures (HS-ST) on the macronutrients and bioactive proteins in HM. As control samples, HM was stored at the same temperatures under 0.1 MPa. A Miris HM analyzer was used to determine the macronutrients and the energy value. The lactoferrin (LF), lysozyme (LYZ) and α-lactalbumin (α-LAC) content was checked using high-performance liquid chromatography, and an ELISA test was used to quantify secretory immunoglobulin A (sIgA). The results showed that the macronutrient content did not change significantly after 90 days of storage at 60 MPa/−5 °C, 78 MPa/−7 °C, 111 MPa/−10 °C or 130 MPa/−12 °C. Retention higher than 90% of LYZ, α-LAC, LF and sIgA was observed in the HM stored at conditions of up to 111 MPa/−10 °C. However, at 130 MPa/−12 °C, there was a reduction in LYZ and LF, by 39 and 89%, respectively. The storage of HM at subzero temperatures at 0.1 MPa did not affect the content of carbohydrates or crude and true protein. For fat and the energy value, significant decreases were observed at −5 °C after 90 days of storage.

Experimental design approach for the quantitative analysis of multicomponents by single marker and HPLC fingerprinting of Thunbergia laurifolia aqueous extract.

Thunbergia laurifolia is used in traditional Thai medicine to reduce fever and treat mouth ulcers. However, the quantitative analysis of chemical markers has not yet been officially defined. The objective of this study is to develop a high-performance liquid chromatography (HPLC) method using a design of experiment (DoE) for the quantitative analysis of multicomponents by single marker (QAMS) and fingerprinting of the T. laurifolia aqueous extract. Critical variables were screened using a two-level fractional factorial design, followed by the optimization of the selected variables using a central composite design. The validated method was applied for quality assessment based on QAMS and fingerprinting of the extract. Optimum conditions of DoE for the analysis of caffeic acid, vicenin-2, and rosmarinic acid were determined. The relative correction factors for caffeic acid and vicenin-2 were calculated using rosmarinic acid as an internal reference standard, and their contents in 30 samples were determined. The differences between the external standard method (ESM) and QAMS were compared. No significant difference was observed in the quantitative determination, proving the consistency QAMS and ESM. HPLC fingerprints of T. laurifolia were established with 8 of 12 characteristic peaks that were structurally characterized using HPLC-diode array detection-electrospray ionization/tandem mass spectrometry. The similarity of the fingerprints in all samples was ≥0.74, and the pattern recognition of the characteristic peaks was satisfied. The proposed method efficiently detected multiple components of the T. laurifolia extract. Thus, the method is beneficial in providing references for enhancing the quality control of other herbal medicines.

Study on the material basis of Zhujing pill in treating fundus lesions through component analysis and network pharmacology.

Zhujing pill (ZP) is a famous Chinese herbal formula that has been widely used to treat diabetic retinopathy, macular degeneration, retinitis pigmentosa and other fundus lesions. In this study, the material basis and mechanism of ZP in the treatment of fundus lesions were evaluated via the high-performance liquid chromatography fingerprint, ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry, network pharmacology and molecular docking. A total of 32 common components were found and 31 components were identified in 15 batches of ZP samples. Moreover, 134 common key targets and 17 putative active components that are connected to fundus lesions were identified. Molecular docking revealed that quercetin, kaempferol, isorhamnetin, 5-O-feruloylquinic acid, plantagoside and 2'-acetylacteoside have the ability to interact with the core targets such as AKT1, TP53, TNF, IL-6 and Jun. Our findings revealed that the therapeutic effects of ZP on fundus lesions are mediated by multiple components, targets and pathways, including at least six active ingredients and 11 targets. The study provides new ideas for further research on the material basis and mechanisms of traditional Chinese medicine prescriptions.

Inflammatory corpuscle AIM2 facilitates macrophage foam cell formation by inhibiting cholesterol efflux protein ABCA1

The inflammatory corpuscle recombinant absents in melanoma 2 (AIM2) and cholesterol efflux protein ATP binding cassette transporter A1(ABCA1) have been reported to play opposing roles in atherosclerosis (AS) plaques. However, the relationship between AIM2 and ABCA1 remains unclear. In this study, we explored the potential connection between AIM2 and ABCA1 in the modulation of AS by bioinformatic analysis combined with in vitro experiments. The GEO database was used to obtain AS transcriptional profiling data; screen differentially expressed genes (DEGs) and construct a weighted gene co-expression network analysis (WGCNA) to obtain AS-related modules. Phorbol myristate acetate (PMA) was used to induce macrophage modelling in THP-1 cells, and ox-LDL was used to induce macrophage foam cell formation. The experiment was divided into Negative Control (NC) group, Model Control (MC) group, AIM2 overexpression + ox-LDL (OE AIM2 + ox-LDL) group, and AIM2 short hairpin RNA + ox-LDL (sh AIM2 + ox-LDL) group. The intracellular cholesterol efflux rate was detected by scintillation counting; high-performance liquid chromatography (HPLC) was used to detect intracellular cholesterol levels; apoptosis levels were detected by TUNEL kit; levels of inflammatory markers (IL-1β, IL-18, ROS, and GSH) were detected by ELISA kits; and levels of AIM2 and ABCA1 proteins were detected by Western blot. Bioinformatic analysis revealed that the turquoise module correlated most strongly with AS, and AIM2 and ABCA1 were co-expressed in the turquoise module with a trend towards negative correlation. In vitro experiments demonstrated that AIM2 inhibited macrophage cholesterol efflux, resulting in increased intracellular cholesterol levels and foam cell formation. Moreover, AIM2 had a synergistic effect with ox-LDL, exacerbating macrophage oxidative stress and inflammatory response. Silencing AIM2 ameliorated the above conditions. Furthermore, the protein expression levels of AIM2 and ABCA1 were consistent with the bioinformatic analysis, showing a negative correlation. AIM2 inhibits ABCA1 expression, causing abnormal cholesterol metabolism in macrophages and ultimately leading to foam cell formation. Inhibiting AIM2 may reverse this process. Overall, our study suggests that AIM2 is a reliable anti-inflammatory therapeutic target for AS. Inhibiting AIM2 expression may reduce foam cell formation and, consequently, inhibit the progression of AS plaques.

Molecularly imprinted polymers using high-performance liquid chromatography to detect and determine ethion pesticide in apricot, grapes, strawberry and soil samples

ABSTRACT This paper demonstrates the synthesis of molecularly imprinted polymers-solid phase extraction-liquid chromatography method at room temperature using bulk polymerisation of ethion pesticide, by high sensitivity, low costs and high stability. By making MIP for ethion as ethion-MIP, which could be detected with a UV-Vis spectrophotometer at 276 nm, a functional monomer of acrylic acid with cross-linking ethylene glycol dimethyl acrylate. The high-performance liquid chromatography methods developed in this study are accurate, sensitive, and precise to apricot, grapes, strawberry and soil samples. The elution process to the template ethion from the ethion-MIP, caused by minimum volume using solution of 1.0 mL of methanol-acetic acid (9:1) was obtained. Different factors affecting the reaction were studied and optimised. The calibration plot is linear in the concentration range of (0.02 to 1.0 µg mL−1). The relative standard deviations of (±2.0%) and detection limit of the method are 0.02 µg mL−1, and the maximum imprinting factor of ethion-MIP was 6.8 mgg−1. The results obtained the evidence of efficiency and reliability of the method for the ethion pesticide analysis and estimation for the capacitance of molecular imprinted polymer, analytical technical method by molecularly imprinted polymer and high-performance liquid chromatography.

Biodegradation of DEP, DIBP, and BBP by a psychrotolerant Sphingobium yanoikuyae strain P4: Degradation potentiality and mechanism study.

Phthalic acid esters (PAEs) are human made chemicals widely used as plasticizers to enhance the flexibility of plastic products. Due to the lack of chemical bonding between phthalates and plastics, these materials can easily enter the environment. Deleterious effects caused by this chemo-pollutant have drawn the attention of the scientific community to remediate them from different ecosystem. In this context, many bacterial strains have been reported across different habitats and Sphingobium yanoikuyae strain P4 is among the few psychrotolerant bacterial species reported to biodegrade simple and complex phthalates. In the present study, biodegradation of three structurally different PAEs viz., diethyl phthalate (DEP), di-isobutyl phthalate (DIBP), and butyl benzyl phthalate (BBP) have been investigated by the strain P4. Quantitative analyses through High-performance liquid chromatography (HPLC) revealed that the bacterium completely degraded 1g/L of DEP, DIBP, and BBP supplemented individually in minimal media pH 7.0 within 72, 54, and 120h of incubation, respectively, at 28°C and under shake culture condition (180rpm). In addition, the strain could grow in minimal media supplemented individually with up to 3g/L of DEP and 10.0g/L of DIBP and BBP at 28°C and pH 7.0. The strain also could grow in metabolites resulting from biodegradation of DEP, DIBP, and BBP, viz. n-butanol, isobutanol, butyric acid, ethanol, benzyl alcohol, benzoic acid, phthalic acid, and protocatechuic acid. Furthermore, phthalic acid and protocatechuic acid were also detected as degradation pathway metabolites of DEP and DIBP by HPLC, which gave an initial idea about the biodegradation pathway(s) of these phthalates.

A Study of the Thermal Degradation of Amoxicillin Trihydrate Using Raman Spectroscopy and High-Performance Liquid Chromatography

A Study of the Thermal Degradation of Amoxicillin Trihydrate Using Raman Spectroscopy and High-Performance Liquid Chromatography

Stability-Indicating HPLC Method for Determination of Ibuprofen and Famotidine Degradation Products.

A new stability-indicating high-performance liquid chromatographic method for the quantitative determination of ibuprofen and famotidine degradation products in combined pharmaceutical products was developed and validated. The current aim of this study is to develop a rapid, accurate and robust analytical stability indicating impurity method that can separate ibuprofen, famotidine and their related impurities by using a reversed-phase high-performance liquid chromatography. A Zorbax SB-Phenyl column (4.6 × 150mm2, 5-μm particle size) with mobile phase containing phosphate buffer solution with a pH value of 3.0 and acetonitrile was used. The flow rate was 0.8mL/min and the analytes were detected by UV detector at 265nm. The retention times of ibuprofen and famotidine were 18.43 and 5.14min, respectively. This method was validated to confirm specificity, linearity, sensitivity (limit of detection and limit of quantitation), precision, accuracy, robustness and sample stability according to the International Conference on Harmonization guidelines. Studies have been completed and reported with two active substances in the combined dosage form and seven impurities in total. There is no method in the literature that simultaneously distinguishes and quantitatively analyzes both active substances and degradation products.