UPLC-MS/MS Based Identification and Quantification of a Novel Dual Orexin Receptor Antagonist in Plasma Samples by Validated SWGTOX Guidelines

Validated UPLC-MS/MS method for quantification of melatonin receptor agonists and dual orexin receptor antagonists in human plasma and breast milk: Application to quantify suvorexant and lemborexant in clinical samples

Pharmaceutical care is important for mental health during the perinatal period, which is often characterized by insomnia. In recent years, prescriptions of melatonin receptor agonists (MRAs) and dual orexin receptor antagonists (DORAs) for insomnia have increased; however, their use during the perinatal period has scarcely been reported. In the present study, we developed a UPLC-MS/MS method for the quantification of ramelteon, its metabolite M-II, suvorexant, and lemborexant in human plasma and breast milk to accumulate information on the safety and transfer of MRAs and DORAs into breast milk. Samples of MRAs (ramelteon and M-II) in plasma and breast milk were prepared using liquid-liquid extraction (LLE) with ethyl acetate. For DORAs (suvorexant and lemborexant), LLE with ethyl acetate was applied to plasma samples. For breast milk samples, significant ion suppression was observed for LLE with ethyl acetate. Solid-phase extraction (SPE) cartridges capable of removing phospholipids improved the matrix effects. Finally, protein precipitation with methanol and an SPE cartridge, InertSep® Phospholipid Remover, were selected for breast milk sample preparation. An ACQUITY UPLC BEH C18 column was used for analyte separation. MRAs and DORAs were eluted using isocratic and gradient elution, respectively, and analyzed using electrospray ionization in the positive mode with multiple reaction monitoring. The range of calibration curve for MRAs and DORAs was 0.1-25 and 0.5-50 ng/ml, respectively. Both the plasma and breast milk samples exhibited good linearity over this range. The method was validated by evaluating its accuracy and precision, matrix effect, recovery, carry-over, stability, and dilution integrity. The validated method was successfully applied to clinical samples donated by breastfeeding women and the milk/plasma (M/P) ratio and relative infant dose (RID) of lemborexant (one case) and suvorexant (two cases) were estimated. The M/P ratio of lemborexant was <1, and the RID was 1.05 %. The M/P ratio of suvorexant was <0.1, and RID was 0.11-0.20 %. This method will be useful for future studies evaluating the safety of these drugs during breastfeeding.

A Simple, Sensitive, and Greener HPLC-DAD Method for the Simultaneous Analysis of Two Novel Orexin Receptor Antagonists

The orexin receptor antagonist (ORA) is one of the new psychopharmacological agents used in the treatment of insomnia. There are currently no documented greener high-performance liquid chromatography-diode array detector (HPLC-DAD) methods for the analysis of ORA antagonists, lemborexant (LMB) and suvorexant (SUV) simultaneously. Therefore, in this study, a simple, sensitive, and greener HPLC-DAD method has been developed for the simultaneous quantitative analysis of LMB and SUV in bulk and laboratory-prepared mixture. The developed method was validated for numerous validation parameters and evaluated for greenness. The C18 Waters Spherisorb CN (4.6 × 250 mm2; 5 μm) column was used for the chromatographic separation. The mobile phase composition was ethanol: 10 mM KH2PO4 buffer in a ratio of (60:40 v/v). The DAD detection was performed at 253 nm using a Waters DAD detector. The greenness was evaluated using the analytical Eco-Scale (AES), ChlorTox, and analytical GREEnness (AGREE) techniques. The calibration curves showed excellent linearity for LMB and SUV between the concentration range of 125-5000 ng/mL and 250-10,000 ng/mL, respectively. In addition, the proposed HPLC-DAD method was accurate, precise, robust, highly sensitive, and greener. AES, ChlorTox, and AGREE scales were predicted by the HPLC-DAD method to be 91, 1.14 g, and 0.79, respectively, showing an excellent greenness profile. The greener HPLC-DAD method was successfully used to analyze both medicines quantitatively in bulk and laboratory-prepared synthetic mixtures. The findings of this study indicated that the proposed HPLC-DAD method may be consistently applied to evaluate LMB and SUV in bulk and dosage forms.

Quantification of Suvorexant in Human Urine Using a Validated HPTLC Bioanalytical Method

Suvorexant (SUV) is a new sedative/hypnotic medicine that is recommended to treat insomnia. It is an important medicine from a forensic point of view due to its sedative/hypnotic and depressant effects. To the best of our knowledge, high-performance thin-layer chromatography (HPTLC) bioanalytical methods have not been published to measure SUV in human urine and pharmaceutical samples. Accordingly, this study was designed and validated a sensitive and rapid bioanalytical HPTLC method to determine SUV in human urine samples for the very first time. The densitometric measurement of SUV and the internal standard (IS; sildenafil) was performed on glass-coated silica gel normal-phase-60F254S TLC plates using a mixture of chloroform and methanol (97.5:2.5 v/v) as the eluent system. Both the SUV and IS were detected at a wavelength of 254 nm. Both analytes were extracted using the protein precipitation technique utilizing methanol as the solvent. For the IS and SUV, the Rf values were 0.09 and 0.45, respectively. The proposed bioanalytical method for SUV was linear in the 50-1600 ng/band range. The current bioanalytical technique was linear, precise (% RSD = 3.28-4.20), accurate (% recovery = 97.58-103.80), robust (% recovery = 95.31-102.34 and % RSD = 2.81-3.15), rapid, and sensitive (LOD = 3.73 ng/band and LOQ = 11.20 ng/band). These findings suggested that the current bioanalytical method can be regularly used to determine SUV in wide varieties of urine samples.

The Identification of Drug Abuse

Forensic toxicology has played a central role since its development in defining mechanisms of acute intoxication, often with a lethal outcome [...].