Simultaneous Quantitation of Paracetamol, Pseudoephedrine and Chlorpheniramine in Dog Plasma by LC-MS-MS

Implementation of different separation techniques for resolving ternary mixture of Paracetamol, Pseudoephedrine Hydrochloride and Chlorpheniramine maleate with further quantification

Due to the wide applicability of separation techniques that rely on the property of differential migration in pharmaceutical formulations analysis, different analytical strategies have been proposed to resolve mixtures of multi-components pharmaceuticals. Three separation methods were developed and validated for the simultaneous determination of Paracetamol (PAR), Pseudoephedrine HCl (PSE) and Chlorpheniramine maleate (CHP). The first method is a thin-layer chromatographic (TLC) separation, followed by densitometric measurement. The separation was carried out on aluminium sheet of silica gel 60 F254 using ethanol:chloroform:ammonia (1:7:0.4, by volume) as the mobile phase. Determination of PAR, PSE and CHP was successfully applied over the concentration ranges of 3–25 µg/band, 0.5–10 µg/band and 0.1–6 µg/band, respectively. The second method is HPLC separation that was achieved on C18 column using the mobile phase acetonitrile:phosphate buffer pH 5 (10:90, v/v) at a flow rate 1 mL min−1. PAR, PSE and CHP were determined by HPLC in concentration ranges of 5–400 μg mL−1, 2–40 μg mL−1 and 0.5–16 μg mL−1, respectively. The third method is a capillary electrophoresis (CE) separation. The electrophoretic separation was achieved using 20 mM phosphate buffer (pH 6.5) at 20 kV. The linearity was reached over concentration ranges of 30–250 μg mL−1, 5–50 μg mL−1 and 0.8–20 μg mL−1 for PAR, PSE and CHP, respectively. The developed methods were validated with respect to linearity, precision, accuracy and system suitability. The proposed methods were successfully applied for bulk powder and dosage form analysis with RSD of precision <2%. Moreover, statistical comparison with the official methods confirms the methods' validity.

A reliable LC-MS/MS method for the quantification of N-acetyl-p-benzoquinoneimine, acetaminophen glutathione and acetaminophen glucuronide in mouse plasma, liver and kidney: Method validation and application to a pharmacokinetic study

A rapid, specific, and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated to simultaneously quantify N-acetyl-p-benzoquinoneimine (NAPQI), acetaminophen-glutathione (acetaminophen-glut) and acetaminophen-glucuronide (acetaminophen-gluc) in mouse plasma, liver and kidney homogenates. Analytes were eluted by a binary gradient mobile phase composed of water (phase A) and methanol containing 0.1% formic acid (phase B) at a flow rate of 0.3 mL/min, which was performed on a CAPCELL PAK C₁₈ MG II column. It took 3.2 min to detect three analytes in a single run. Quantification was carried out in positive mode combined with multiple reaction monitoring. The validation of the LC-MS/MS method consisted of specificity, linearity, precision, accuracy, protein precipitation recovery, matrix effect, dilution integrity and stability. The plasma and tissue homogenate calibration curves were linear over concentration ranges of 0.050-5.00, 0.050-5.00 and 0.100-40.0 μg/mL, with a lower limit of quantification of 0.050, 0.050, and 0.100 μg/mL for NAPQI, acetaminophen-glut and acetaminophen-gluc, respectively. The intra- and inter-run precision values were within 12.47% for NAPQI, 12.11% for acetaminophen-glut and 11.86% for acetaminophen-gluc at their lower limit of quantitation levels. The samples were stable under all tested conditions. This method was successfully applied to study the pharmacokinetics of NAPQI, acetaminophen-glut and acetaminophen-gluc in ICR mice following oral administration of 200 mg/kg of acetaminophen suspension.

The novel, potent and highly selective 5-HT4 receptor agonist YH12852 significantly improves both upper and lower gastrointestinal motility

BACKGROUND AND PURPOSE

5-HT₄ receptor agonists have been shown to be effective at treating various gastrointestinal tract disorders. However, a lack of selectivity against off-targets has been a limiting factor for their clinical use.

EXPERIMENTAL APPROACH

The binding affinity and selectivity of YH12852 for human 5-HT_4(a) receptor in CHO-K1 cells were evaluated using radioligand binding assays, and agonistic activity was assessed using a β-lactamase reporter system. Contractile activity and propulsive motility were measured in the guinea pig isolated distal colon. Its prokinetic effect on the gastrointestinal tract was evaluated in guinea pigs, dogs and monkeys. Its tissue distribution was evaluated in rats.

KEY RESULTS

YH12852 exhibited high affinity and potency for human recombinant 5-HT_4(a) receptor with high selectivity over other 5-HT and non-5-HT receptors, ion channels, enzymes and transporters. YH12852 induced contractions and increased propulsive motility in guinea pig isolated colon. These effects were abolished by the 5-HT₄ receptor antagonist GR113808. YH12852 increased defecation more effectively than prucalopride in guinea pigs and dogs and improved gastric emptying more effectively than mosapride in guinea pigs, dogs and monkeys. YH12852 was highly distributed to the gastrointestinal tract as the target organ.

CONCLUSION AND IMPLICATIONS

The high in vitro potency and selectivity of YH12852 for 5-HT₄ receptor translated into potent in vivo efficacy with good tolerability. YH12852 significantly improved both upper and lower bowel motility in the animal models tested and has the potential to address considerable unmet needs in patients with functional constipation, gastroparesis or both.

Fast Determination of Ingredients in Solid Pharmaceuticals by Microwave-Enhanced In-Source Decay of Microwave Plasma Torch Mass Spectrometry

Rapid qualitative and quantitative analysis of solid samples (e.g., pharmaceutical preparations) by using a small and low-resolution mass spectrometer without MS/MS function is still a challenge in ambient pressure ionization mass spectrometric analysis. Herein, a practically efficient method termed microwave-enhanced in-source decay (MEISD) using microwave plasma torch desorption ionization coupled with time-of-flight mass spectrometry (MPTDI-TOF MS) was developed for fast analysis of pharmaceutical tablets using a miniature TOF mass spectrometer without tandem mass function. The intensity of ISD fragmentation was evaluated under different microwave power values. Several factors, including desorption distance and time that might affect the signal intensity and fragmentation, were systematically investigated. It was observed that both the protonated molecular ions and major fragment ions from the active ingredients in tablets could be found in the full-scan mass spectra in positive ion mode, which were comparable to those obtained by a commercial LTQ-XL ion trap mass spectrometer. The structures of the ingredients could be elucidated in detail using the MEISD method, which promotes our understanding of the desorption/ionization processes in microwave plasma torch (MPT). Quantitative analysis of 10 tablets was achieved by full-scan MPTDI-TOF MS with low limit of detection (LOD, 0.763 mg/g), acceptable relative standard deviation (RSD < 7.33%, n =10), and 10 s for each tablet, showing promising applications in high throughput screening of counterfeit drugs. Graphical Abstract ᅟ.