SIL-IS LC-ESI-MS/MS method for simultaneous quick detection of amoxicillin and clavulanic acid in human plasma: Development, validation and its application to a pharmacokinetics study

A liquid chromatography electrospray ionization tandem mass spectrometry method with amoxicillin-d4 as the stable isotope-labeled internal standard for simultaneous quick detection of amoxicillin and clavulanic acid in human plasma was developed and validated. Chromatographic separations were performed on a Hedera ODS-2 column (2.1 × 150 mm, 5 μm). The mobile phases for gradient elution were aqueous solution containing 0.2% acetic acid (AA) (mobile phase A) together with organic phase solution (acetonitrile and methanol mixed solution, mobile phase B). Mass spectrometry was performed using negative electrospray ionization in multiple reaction monitoring mode. The target fragment ion pairs of amoxicillin, clavulanic acid and amoxicillin-d4 were m/z 364.1 → 223.1, 198.1 → 135.9 and 368.1 → 227.1, respectively. The linear ranges of this method were 40-5,000 ng/ml for amoxicillin and 30-2,500 ng/ml for clavulanic acid, with coefficient of determination > 0.9900. This method validation included selectivity, standard curve, lower limit of quantitation, accuracy, precision, recovery, matrix effect (hemolytic matrix and hyperlipidemic matrix), carryover, stability, dilution reliability and incurred sample reanalysis study. A successful application of this method was realized in a pharmacokinetic study after administration of amoxicillin-clavulanic acid potassium granules.

A Comprehensive Study to Determine the Residual Elimination Pattern of Major Metabolites of Amoxicillin-Sulbactam Hybrid Molecules in Rats by UPLC-MS/MS

Amoxicillin and sulbactam are widely used in animal food compounding. Amoxicillin-sulbactam hybrid molecules are bicester compounds made by linking amoxicillin and sulbactam with methylene groups and have good application prospects. However, the residual elimination pattern of these hybrid molecules in animals needs to be explored. In the present study, the amoxicillin-sulbactam hybrid molecule (AS group) and a mixture of amoxicillin and sulbactam (mixture group) were administered to rats by gavage, and the levels of the major metabolites of amoxicillin, amoxicilloic acid, amoxicillin diketopiperazine, and sulbactam were determined by UPLC-MS/MS. The residue elimination patterns of the major metabolites in the liver, kidney, urine, and feces of rats in the AS group and the mixture group were compared. The results showed that the total amount of amoxicillin, amoxicilloic acid, amoxicillin diketopiperazine, and the highest concentration of sulbactam in the liver and kidney samples of the AS group and the mixture group appeared at 1 h after drug withdrawal. Between 1 h and 12 h post discontinuation, the total amount of amoxicillin, amoxicilloic acid, and amoxicillin diketopiperazine in the two tissues decreased rapidly, and the elimination half-life of the AS group was significantly higher than that in the mixture group (p < 0.05); the residual amount of sulbactam also decreased rapidly, and the elimination half-life was not significantly different (p > 0.05). In 72 h urine samples, the total excretion rates were 60.61 ± 2.13% and 62.62 ± 1.73% in the AS group and mixture group, respectively. The total excretion rates of fecal samples (at 72 h) for the AS group and mixture group were 9.54 ± 0.26% and 10.60 ± 0.24%, respectively. These results showed that the total quantity of amoxicillin, amoxicilloic acid, and amoxicillin diketopiperazine was eliminated more slowly in the liver and kidney of the AS group than those of the mixture group and that the excretion rate through urine and feces was essentially the same for both groups. The residual elimination pattern of the hybrid molecule in rats determined in this study provides a theoretical basis for the in-depth development and application of hybrid molecules, as well as guidelines for the development of similar drugs.

Sensitive and rapid method for the quantitation of amoxicillin in minipig plasma and milk by LC-MS/MS: A contribution from the IMI ConcePTION project

The IMI project ConcePTION was launched to fill the knowledge gap of using medicines during pregnancy and lactation. To achieve this goal, several studies are being conducted, including the bioanalysis of amoxicillin in minipig plasma and milk. A high-throughput, robust and reliable liquid chromatography tandem mass spectrometry method was developed and validated according to FDA and EMA guidelines to determine the concentrations of amoxicillin in a large number of minipig plasma and milk samples. Chromatographic separation was achieved on a Luna® Omega Polar C18, 1.6 μm, 100 × 2.1 mm column, with a mobile phase consisting of 0.1% formic acid in water and acetonitrile. Mass spectrometry used in a positive ionization mode and the transitions m/z 366.1 → 349.2 was selected to monitor amoxicillin, while m/z 370.1 → 114.15 was selected for the stable isotope labelled internal standard. This method features a linear quantification range of 10 ng/mL - 10 μg/mL, recovery of not less than 94.1%, a single sample extraction method for both plasma and milk matrices, and an analysis runtime of 5 min.

Quantitation of 10 antibiotics in plasma: sulfosalicylic acid combined with 2D-LC-MS/MS is a robust assay for beta-lactam therapeutic drug monitoring

Therapeutic drug monitoring (TDM) of antibiotics is particularly important in populations with high pharmacokinetic variabilities, such as critically ill patients, leading to unpredictable plasma concentrations and clinical outcomes. Here, we i) describe an original method for the simultaneous quantification of ten antibiotics (cefepime, ceftazidime, ampicillin, piperacillin/tazobactam, cefotaxime, amoxicillin, cloxacillin, oxacillin, linezolid) using 5-sulfosalicylic acid dihydrate (SSA) solution for protein precipitation together with 2D-LC-MS/MS, and ii) evaluate its impact in a one-year retrospective study. The method involved simple dilution with an aqueous mix of deuterated internal standards and plasma protein precipitation with SSA. Twenty microliters of the supernatant was injected into a C8 SPE online cartridge (30 × 2.1 mm) without any evaporation step and back-flushed onto a C18 UHPLC (100 × 2.1 mm) analytical column. Mass spectrometry detection (Xevo TQD) was performed in positive electrospray, in scheduled MRM mode. Overall analytical runtime was 7 min. Due to analytical constraints and the physicochemical properties of the antibiotics, protein precipitation using organic solvents could not be applied. As an alternative, SSA used with 2D-LC offered various advantages: i) lack of dilution resulting in better assay sensitivity, and ii) good chromatography of hydrophilic compounds. Ten microliters of 30% SSA in water eliminated>90% of plasma proteins, including the most abundant high molecular weight proteins at 55 and 72 kDa. The assay was successfully validated according to FDA and EMA guidelines for all the antibiotics, and the coefficients of variation of the quality control (QC) run during sample analysis over one year were below 10%, whatever the QC levels or the antibiotics. The use of 2D-LC combined with SSA precipitation allowed development of a robust, sensitive and rapid quantification assay. Feedback to clinicians was reduced to 24 h, thus allowing rapid dosage adjustment. During one year, 3,304 determinations were performed in our laboratory: 41% were not in the therapeutic range, 58% of which were sub-therapeutic, underlining the importance of early TDM of antibiotics to limit therapeutic failures and the emergence of bacterial resistance.

Pharmacokinetics of Amoxicillin and Clavulanate Potassium for Suspension (200 mg/28.5 mg) in Healthy Subjects: Sample Add Stabilizer Study and Food Effects

The present study compares the pharmacokinetics of amoxicillin and clavulanate potassium suspension (200 mg/28.5 mg) during fasting and postprandial conditions, and the sample adds a stabilizer study. Two randomized, crossover trials were conducted in an open-label, single-center study (a fasting trial and a postprandial trial). In each part of the study, the subjects were randomly assigned to receive either test or reference products (200 mg/28.5 mg) in a 1:1:1 ratio, followed by the alternative products after a 7-day washout period. Plasma amoxicillin and clavulanic acid concentrations were analyzed by liquid chromatography-tandem mass spectrometry. WinNonlin software was used to evaluate the pharmacokinetic parameters (noncompartmental model). The formulations were considered bioequivalent if the geometric means of area under the plasma concentration-time curve (AUC) and maximum plasma concentration (C_max ) of amoxicillin and clavulanic acid were within the predetermined bioequivalence range established by average bioequivalence (ABE) or reference-scaled ABE. Tolerability was assessed throughout the study. The postprandial trial and the fasting study each had 12 volunteers. Under fasting and postprandial conditions, the 90%CI for the ratio of geometric means of amoxicillin of C_max , AUC from time 0 to the last measurable concentration, and AUC from time 0 to infinity were within the ABE acceptance limits (80%-125%); the geometric means of clavulanic acid of C_max (critbound, -0.03; point estimate, 1.07) were within the reference-scaled ABE acceptance limits, and the AUC from time 0 to the last measurable concentration and AUC from time 0 to infinity were within the ABE acceptance limits (80%-125%). Time to maximum concentration of amoxicillin was delayed 1.0 hour with high-fat meals compared to fasting conditions. Meantime, high-fat meals decreased the exposure of clavulanic acid by nearly 40%. No serious adverse events were found among the subjects. The bioequivalence of test and reference amoxicillin and clavulanate potassium for suspension was validated in this study under fasting and postprandial conditions.

Quantitative determination of characteristic components from compound of Lysionotus pauciflorus Maxim. by LC-MS/MS and its application to a pharmacokinetic study

Tuberculosis of cervical lymph nodes is called scrofula in Traditional Chinese Medicine (TCM). Clinical manifestation is that unilateral or bilateral neck can have multiple enlarged lymph nodes of different sizes. Current therapeutic drugs include Lysionotus pauciflorus Maxim. tablets and compound of Lysionotus pauciflorus Maxim., which have a significant effect on tuberculosis of cervical lymph nodes. This compound is composed of three herbs, Lysionotus pauciflorus Maxim., Prunella vulgaris L. and Artemisia argyi Levl.et Vant. A selective and sensitive LC-MS/MS method was established and validated in rat plasma for the first time. Chromatographic separation was achieved on a Wonda Cract ODS-2 C18 Column (150 mm × 4.6 mm, 5 μm). The mobile phase contained 0.1% formic acid aqueous solution and acetonitrile with a flow rate of 0.8 mL/min. The detection was performed in negative electrospray ionization mode and the precursor/product ion transitions of six components and internal standard (IS) sulfamethoxazole were quantified in multiple reaction monitoring (MRM) using QTRAP-3200 MS/MS. The method fulfilled US Food and Drug Administration guidelines for selectivity, sensitivity, accuracy, precision, matrix effect, extraction recovery, dilution integrity, and stability. This proposed method was then successfully applied to a pharmacokinetic study after oral administration of 10 mL/kg compound extracts in rats. The pharmacokinetic parameters and plasma concentration-time profiles would prove valuable in pre-clinical and clinical investigations on the disposition of compound medicine.

Application of novel ternary deep eutectic solvents as a functional monomer in molecularly imprinted polymers for purification of levofloxacin

A series of ecofriendly ternary deep eutectic solvents (DESs) with different molar ratios were prepared as candidate functional monomers. Three of the optimal ternary DESs as functional monomers were applied to the preparation of molecularly imprinted polymers (MIPs). After synthesis, the proposed polymers were characterized by elemental analysis (EA), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), Brunauer-Emmett-Teller surface area measurements (BET) and Fourier transform infrared spectroscopy (FT-IR). These MIPs based on ternary DESs with different molar ratios exhibited different absorption capacities of levofloxacin. A sample of levofloxacin (500ng) was dissolved in a millet extractive (10mL). All MIPs were used as SPE adsorbents to purify the extracts. According to characterization result, the ternary DES-3 (1:3:1.5) was joined in the synthetic process of MIP-1. The green ternary DES-3-based MIPs had the best selectivity recovery for levofloxacin (91.4%) from the millet extractive. The best selectivity of MIP-1 was attributed to the novel monomer (ternary DES) in the preparation of the materials. Overall, ternary DES-based MIPs have potential applications as media in many research areas.