Determination of lercanidipine in human plasma by an improved UPLC-MS/MS method for a bioequivalence study

Development, validation, and implementation of an ultratrace analysis method for the determination of moenomycin A, in aquatic animal products

Moenomycin A, an antimicrobial growth promoter widely used as an additive in aquaculture feedstuffs, has been restricted for use in the European Union and China due to its potential risk of promoting resistant strains of pathogenic bacteria and causing residues in aquatic animal products. Although methods for analyzing moenomycin A in feedstuffs have been developed, no established method exists for aquatic matrices. In this study, we present, for the first time, a sensitive and validated high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for the determination of moenomycin A in aquatic animal products. Samples were extracted using methanol and purified with the QuEChERS method employing C18 sorbent. The aliquot was dried under a nitrogen stream, reconstituted with methanol-water solvent, and analyzed by HPLC-MS/MS. The developed method exhibited good linearity (r2 > 0.995) over a wide concentration range (1-100 μg/L) and a low limit of detection (1 µg/kg). Average recoveries ranged between 70 and 110% at spiked concentrations of 1, 50, and 100 μg/kg, with associated intra- and inter-day relative standard deviations of 1.25 to 7.32% (n = 6) and 2.91 to 10.08% (n = 3), for different representative aquatic animal production, respectively. To the best of our knowledge, this is the first reported HPLC-MS/MS method for the quantification of moenomycin A in aquatic animal products. The new approach was effectively employed in the analysis of moenomycin A across various aquatic samples.

Exploring DrugCentral: from molecular structures to clinical effects

DrugCentral, accessible at https://drugcentral.org , is an open-access online drug information repository. It covers over 4950 drugs, incorporating structural, physicochemical, and pharmacological details to support drug discovery, development, and repositioning. With around 20,000 bioactivity data points, manual curation enhances information from several major digital sources. Approximately 724 mechanism-of-action (MoA) targets offer updated drug target insights. The platform captures clinical data: over 14,300 on- and off-label uses, 27,000 contraindications, and around 340,000 adverse drug events from pharmacovigilance reports. DrugCentral encompasses information from molecular structures to marketed formulations, providing a comprehensive pharmaceutical reference. Users can easily navigate basic drug information and key features, making DrugCentral a versatile, unique resource. Furthermore, we present a use-case example where we utilize experimentally determined data from DrugCentral to support drug repurposing. A minimum activity threshold t should be considered against novel targets to repurpose a drug. Analyzing 1156 bioactivities for human MoA targets suggests a general threshold of 1 µM: t = 6 when expressed as - log[Activity(M)]). This applies to 87% of the drugs. Moreover, t can be refined empirically based on water solubility (S): t = 3 - logS, for logS < - 3. Alongside the drug repurposing classification scheme, which considers intellectual property rights, market exclusivity protections, and market accessibility, DrugCentral provides valuable data to prioritize candidates for drug repurposing programs efficiently.

Restricted access polypyrrole employed in pipette-tip solid-phase extraction for determination of nimodipine and nicardipine in breast milk

A HPLC-UV method for the determination of nimodipine and nicardipine in breast milk using restricted access polypyrrole as an adsorbent in pipette-tip solid-phase extraction (PT-SPE) has been developed. The chromatographic conditions were a C₁₈ column (150 mm × 4.60 mm, 5 μm) using methanol : acetonitrile : ultrapure water (55 : 30 : 15, v/v/v) at a flow rate of 1.0 mL min^-1 and detection at 236 nm. The adsorbents have been synthesized and characterized by using Fourier-transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, surface analysis, wettability and point zero charge, and were then applied in sample preparation. The main parameters that affect analyte recovery from breast milk by PT-SPE were optimized and the analytical method showed recoveries around 100%, linearity from 3 to 3000 ng mL^-1, and correlation coefficients (r) ≥ 0.99 for the two analytes, in addition to adequate precision, accuracy and robustness. Finally, the validated method has been successfully applied in analyses of breast milk from volunteers.

[Lercanidipine distribution in warm-blooded animals]

THE AIM OF THE STUDY

Is to investigate the lercadipine distribution in warm-blooded animals (rats). The experimental study used rats of Wistar race. TLC, GC-MS and UV-spectrophotometry methods were used for physical and chemical analysis. Semilethal (890 mg/kg) dose of lercadipine, previously suspended in water, was injected into stomach of laboratory animals. Examined substance was isolated from the thick tissues and animals' blood by acetone, cleaned with a change of solvent and macrocolumn chromatography using 30 µm «Silasorb S-18» sorbent and acetonitrile-water (8:2) polar eluent. The analyte was identified by chromatographic behavior in the thin sorbent layer, retention time and set of positive ions in its mass spectrum, as well as by UV-spectrum. The analyte was determined quantitatively in bioactive matrix using UV-spectrophotometry. The methods were validated by criteria of linearity, selectivity, accuracy, precision, detection limits and quantitative determination. The main content of lercanidipine (mg/100 g) was determined in the stomach content (198.183±29.541), the stomach (195.312±21.579), the small intestine (47.096±3.947), the spleen (38.952±3.532) and the liver (26.211±2.232).

Development of three ecological spectroscopic methods for analysis of betrixaban either alone or in mixture with lercanidipine: greenness assessment

Three eco-friendly spectrophotometric methods were developed for determination of the novel anticoagulant drug, betrixaban (BTX). The first method (method A) was based on direct analysis of BTX at 229.4 nm on the zero-order spectrum using methanol as the optimum solvent. While the second method (method B) was based on measuring difference absorption value (ΔA) of BTX at 335 nm, which was obtained from pH-induced spectral difference (difference spectra of BTX in 0.1 M NaOH versus 0.1 M HCl). The third method (method C) was based on measurement of the first-derivative amplitudes of BTX and its co-administered Ca channel blocker lercanidipine (LER) at 304 and 229 nm for simultaneous assay of BTX and LER, respectively. All methods were linear over concentration ranges of 1.0-20.0 and 8.0-80.0 µg ml^-1 for BTX in methods A and B, respectively, and of 1.0-20.0 and 1.0-25.0 µg ml^-1 for BTX and LER, respectively, in method C. The three methods were fully validated and assessed for greenness by three metrics: analytical eco-scale, green analytical procedure index and Analytical GREEnness metrics. The results indicated the validity and greenness of the proposed methods. Moreover, the methods were applied to assay the studied analytes in their dosage forms with high percentage of recovery and low percentage of relative s.d. values.

Optimization and Validation of a Facile RP-HPLC Method for Determination of Betrixaban and Lercanidipine in Pharmaceutical and Biological Matrices

A simple, accurate, rapid and sensitive reversed-phase high-performance liquid chromatography (RP-HPLC) method was established for determination of a novel non-vitamin K antagonist oral anticoagulant drug, betrixaban, and its co-administered calcium-channel blocker drug, lercanidipine, in pharmaceutical formulations and biological fluids. The proposed HPLC method was the first chromatographic method applied to estimate this mixture in a short chromatographic run (<6 min), high resolution between betrixaban/lercanidipine (Rs = 7.12) and acceptable values of limit of detection (LOD), limit of quantification (LOQ) and percentage of relative standard deviation (%RSD). The chromatographic separation was performed on a cyano column using a mobile phase composed of acetonitrile:methanol:water (35:35:30, v/v/v) containing 0.2% orthophosphoric acid adjusted to pH 3.2 by triethylamine, programmed with a flow rate of 1 mL/min with UV detection at 240 nm. The proposed method showed linearity over the concentration ranges of (0.20-20.0 μg/mL) and (0.25-25.0 μg/mL) for betrixaban and lercanidipine, respectively. All validation parameters met the acceptance criteria according to ICH guidelines in terms of linearity, LOD, LOQ, accuracy, precision, robustness, specificity and system suitability. The method was applied to assay the studied analytes in their pharmaceutical formulations with high % recovery (98-102%) and low %RSD (<1.5). Furthermore, the proposed method was successfully applied for the determination of betrixaban in spiked human plasma.

Exploratory Study on Lercanidipine Hydrochloride Polymorphism: pH-Dependent Solubility Behavior and Simulation of its Impact on Pharmacokinetics

This work describes an exploratory experimental and in silico study of the influence of polymorphism, particle size, and physiology on the pharmacokinetics of lercanidipine hydrochloride (LHC). Equilibrium and kinetic solubility studies were performed on LHC forms I and II, as a function of pH and buffer composition. GastroPlus® was used to evaluate the potential effect of solubility differences due to polymorphism, particle size, and physiological conditions, on the drug pharmacokinetics. The results indicated that solubilities of LHC polymorphs are strongly dependent on the composition and pH of the buffer media. The concentration ratio (C_I/C_II) is particularly large for chloride buffer (C_I/C_II = 3.3-3.9) and exhibits a slightly decreasing tendency with the pH increase for all other buffers. Based on solubility alone, a higher bioavailability of form I might be expected. However, exploratory PBPK simulations suggested that (i) under usual fasted (pH 1.3) and fed (pH 4.9) gastric conditions, the two polymorphs have similar bioavailability, regardless of the particle size; (ii) at high gastric pH in the fasted state (e.g., pH 3.0), the bioavailability of form II can be considerably lower than that of form I, unless the particle size is < 20 μm. This study demonstrates the importance of investigating the effect of the buffer nature when evaluating the solubility of ionizable polymorphic substances. It also showcases the benefits of using PBPK simulations, to assess the risk and pharmacokinetic relevance of different solubility and particle size between crystal forms, for diverse physiological conditions.

Benefit of serum drug monitoring complementing urine analysis to assess adherence to antihypertensive drugs in first-line therapy

With obesity having doubled in the last decade, hypertension is on the rise. In one-third of hypertensive patients the metabolic syndrome is present. This might be one factor for the increasing number of prescriptions for angiotensin receptor blockers and calcium-channel blockers besides a more favorable risk-to-benefit ratio. The aim of the present study was to evaluate a therapeutic drug monitoring (TDM) method for assessment of adherence based on cut-offs in inpatients and to compare it to an established urine drug screening in outpatients. A method for quantification of calcium-channel blockers and angiotensin receptor blockers using high-performance liquid chromatography-tandem mass spectrometric analysis (LC-MS/MS) was developed and validated. The method was applied to serum samples of 32 patients under supervised medication to establish cut-off values for adherence assessment based on dose-related concentrations (DRC, calculated from pharmacokinetic data). Furthermore, corresponding urine and blood samples of 42 outpatients without supervised medication were analysed and the results compared with regard to adherence assessment. All serum concentrations measured for amlodipine (n = 40), lercanidipine (n = 14), candesartan (n = 10), telmisartan (n = 4) and valsartan (n = 10) in inpatients were above the patient specific lower DRC confirming adherence. Of 42 outpatients the identification of analytes in urine as well as the quantification in serum exhibited differing results. According to urinalysis, adherence was demonstrated in only 87.0% of prescriptions, compared to 91.3% for serum analyses. Differences were observed for amlodipine, lercanidipine and candesartan which can be explained by a higher specificity of the serum analysis approach due to pharmacokinetics. The present study confirms that assessing adherence based on serum drug concentrations with individually calculated lower DRCs is more accurate than using qualitative urine analysis. In particular, drugs with low bioavailability, low renal excretion or high metabolism rate such as lercanidipine and candesartan may lead to underestimation of adherence via urine analysis.

Recent Advances on Drug Analyses Using Ultra Performance Liquid Chromatographic Techniques and their Application to the Biological Samples

Introduction:

Ultra-Performance Liquid Chromatographic (UPLC) method enables analyst to establish an analysis at higher pressure than High Performance Liquid Chromatographic (HPLC) method towards liquid chromatographic methods. UPLC method provides the opportunity to study a higher pressure compared to HPLC, and therefore smaller column in terms of particle size and internal diameter are generally used in drug analysis. The UPLC method has attracted gradually due to its advantages such as short analysis time, the small amount of waste reagents and the significant savings in the cost of their destruction process. In this review, the recent selected studies related to the UPLC method and its method validation are summarized. The drug analyses and the results of the studies which were investigated by UPLC method, with certain parameters from literature are presented.

Background:

Quantitative determination of drug active substances by High-Performance Liquid Chromatography (HPLC) from Liquid Chromatography (LC) methods has been carried out since the 1970's with the use of standard analytical LC methods. In today's conditions, rapid and very fast even ultra-fast, flow rates are achieved compared to conventional HPLC due to shortening analysis times, increasing method efficiency and resolution, reducing sample volume (and hence injection volume), reducing waste mobile phase. Using smaller particles, the speed and peak capacity are expanding to new limit and this technology is named as Ultra Performance Liquid Chromatography. In recent years, as a general trend in liquid chromatography, ultra-performance liquid chromatography has taken the place of HPLC methods. The time of analysis was for several minutes, now with a total analysis time of around 1-2 minutes. The benefits of transferring HPLC to UPLC are much better understood when considering the thousands of analyzes performed for each active substance, in order to reduce the cost of analytical laboratories where relevant analysis of drug active substances are performed without lowering the cost of research and development activities.

Methods:

The German Chemist Friedrich Ferdinand Runge, proposed the use of reactive impregnated filter paper for the identification of dyestuffs in 1855 and at that time the first chromatographic method in which a liquid mobile phase was used, was reviewed. Christian Friedrich Chönbein, who reported that the substances were dragged at different speeds in the filter paper due to capillary effect, was followed by the Russian botanist Mikhail S. Tswet, who planted studies on color pigment in 1906. Tswet observes the color separations of many plant pigments, such as chlorophyll and xanthophyll when he passes the plant pigment extract isolated from plant through the powder CaCO3 that he filled in the glass column. This method based on color separation gives the name of "chromatographie" chromatography by using the words "chroma" meaning "Latin" and "graphein" meaning writing.

Results and Conclusion:

Because the UPLC method can be run smoothly at higher pressures than the HPLC method, it offers the possibility of analyzing using much smaller column sizes and column diameters. Moreover, UPLC method has advantages, such as short analysis time, the small amount of waste reagents and the significant savings in the cost of their destruction process. The use of the UPLC method especially analyses in biological samples such as human plasma, brain sample, rat plasma, etc. increasingly time-consuming due to the fact that the analysis time is very short compared to the HPLC, because of the small amount of waste analytes and the considerable savings in their cost.