Transfer of the Dual Orexin Receptor Antagonist Daridorexant into Breast Milk of Healthy Lactating Women

Transfer of the Oral Gonadotropin-Releasing Hormone Receptor Antagonist Relugolix Into Breast Milk of Healthy Lactating Women

Relugolix is an oral gonadotropin-releasing hormone receptor antagonist that suppresses sex steroid hormones and is approved as monotherapy for prostate cancer and as a fixed-dose combination with estradiol/norethindrone for the treatment of endometriosis and uterine fibroids. The aim of this postmarketing study was to determine the pharmacokinetics and quantify the amount of relugolix excreted into breast milk of healthy lactating women. Following a single, oral dose of 40 mg relugolix, breast milk was sampled over 120 h. Pharmacokinetic parameters were determined, including the cumulative amount of relugolix excreted into breast milk to derive the total infant dose. The safety and tolerability of relugolix were also assessed. Eight healthy lactating women were enrolled and completed the study per protocol. Relugolix was safe and well tolerated based on adverse events and other safety data. It was excreted into breast milk with a median time to peak concentration (tmax) of 5.81 h and a geometric mean peak concentration (Cmax) of 15.7 ng/mL, similar to corresponding plasma data from previous clinical studies. The mean cumulative amount of relugolix excreted was 0.0051 mg over 24 h and 0.0067 mg over 120 h, corresponding to 0.0128% and 0.0167% of the maternal dose, respectively. The body weight-adjusted relative daily infant dose of approximately 0.25% suggests a 400-fold lower newborn than maternal relugolix exposure. Relevant effects of relugolix on the breastfed child appear unlikely given its limited excretion into breast milk of lactating women but cannot be fully excluded in the absence of infant safety data.

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.