Pharmacokinetics, mass balance, and metabolism of [14C]TPN171, a novel PDE5 inhibitor, in humans for the treatment of pulmonary arterial hypertension

Pharmacokinetics and metabolite identification of 23-hydroxybetulinic acid in rats by using liquid chromatography-mass spectrometry method

23-hydroxybetulinic acid (23-HA), a main bioactive component isolated from Pulsatilla chinensis (Bunge) Regel, exhibits various pharmacological activities, such as antimelanoma, antileukemia, anti-colon cancer, and antihepatotoxicity. Although the main active ingredient anemoside B4 (AB4) from this plant has been well studied, research on its active metabolite 23-HA is limited. In the present study, a validated HPLC-QQQ-MS/MS method was established for the quantification of 23-HA in rat plasma. Pharmacokinetics analysis showed that the absorption and elimination of 23-HA in rats were rapid, with an oral bioavailability as 12.9 %. After oral administration with 50 mg/kg 23-HA for SD rats, the plasma, urine, feces, and bile samples were collected and analyzed by UPLC-Q Exactive Plus MS and HPLC-QQQ-MS/MS. Seventeen metabolites of 23-HA were identified, and its major metabolic pathways included oxidation, hydration, sulfation, and glucuronidation. This study highlights the first detailed investigation of 23-HA's pharmacokinetics in rats along with its metabolism in vivo, and will provide robust evidence for further research and clinical application of 23-HA.

Pharmacokinetics, Mass Balance and Metabolism of [14C]HSK21542, a Novel Kappa Opioid Receptor Agonist, in Humans

BACKGROUND AND OBJECTIVE

HSK21542, a synthetic short-chain polypeptide, is a selective peripheral kappa opioid receptor (KOR) agonist. In this single-centre, non-randomized, open-label study, the pharmacokinetics, mass balance, metabolism and excretion of HSK21542 were investigated.

METHODS

A single intravenous dose of 2 μg/0.212 μCi/kg [14C]HSK21542 was administered to six healthy male subjects. Samples of blood, urine and faeces were collected for quantitative determination of total radioactivity and unchanged HSK21542, and identification of metabolites.

RESULTS

The mean total recovery was 81.89% of the radiolabelled dose over 240 h post-dose, with 35.60% and 46.30% excreted in faeces and urine, respectively. The mean maximum concentration (Cmax), the half-life (t1/2) and the area under the concentration-time curve (AUC0-t) of total radioactivity (TRA) in plasma were 20.4 ±4.16 ng Eq./g, 1.93 ± 0.322 h and 21.8 ± 2.93 h·ng Eq./g, respectively, while the Cmax, t1/2 and the AUC0-t of unchanged HSK21542 were 18.3 ± 3.36 ng/mL, 1.66 ± 0.185 h and 18.4 ± 2.24 h·ng/mL, respectively. The blood-to-plasma ratios of TRA at several times ranged from 0.46 to 0.54. [14C]HSK21542 was detected as the main circulating substance in plasma, accounting for 92.17% of the AUC of TRA. The unchanged parent compound was the only major radioactive chemical in urine (100.00% of TRA) and faeces (93.53% of TRA). Metabolites were very minor components.

CONCLUSIONS

HSK21542 was barely metabolized in vivo and mainly excreted with unchanged HSK21542 as its main circulating component in plasma. It was speculated that renal excretion was the principal excretion pathway, and faecal excretion was the secondary pathway.

CLINICAL TRIAL REGISTRATION NUMBER

NCT05835934.

Advancements in Phosphodiesterase 5 Inhibitors: Unveiling Present and Future Perspectives

Phosphodiesterase 5 (PDE5) inhibitors presented themselves as important players in the nitric oxide/cGMP pathway, thus exerting a profound impact on various physiological and pathological processes. Beyond their well-known efficacy in treating male erectile dysfunction (ED) and pulmonary arterial hypertension (PAH), a plethora of studies have unveiled their significance in the treatment of a myriad of other diseases, including cognitive functions, heart failure, multiple drug resistance in cancer therapy, immune diseases, systemic sclerosis and others. This comprehensive review aims to provide an updated assessment of the crucial role played by PDE5 inhibitors (PDE5-Is) as disease-modifying agents taking their limiting side effects into consideration. From a medicinal chemistry and drug discovery perspective, the published PDE5-Is over the last 10 years and their binding characteristics are systemically discussed, and advancement in properties is exposed. A persistent challenge encountered with these agents lies in their limited isozyme selectivity; considering this obstacle, this review also highlights the breakthrough development of the recently reported PDE5 allosteric inhibitors, which exhibit an unparalleled level of selectivity that was rarely achievable by competitive inhibitors. The implications and potential impact of these novel allosteric inhibitors are meticulously explored. Additionally, the concept of multi-targeted ligands is critically evaluated in relation to PDE5-Is by inspecting the broader spectrum of their molecular interactions and effects. The objective of this review is to provide insight into the design of potent, selective PDE5-Is and an overview of their biological function, limitations, challenges, therapeutic potentials, undergoing clinical trials, future prospects and emerging uses, thus guiding upcoming endeavors in both academia and industry within this domain.

Medical Management of Pulmonary Arterial Hypertension: Current Approaches and Investigational Drugs

Pulmonary arterial hypertension (PAH) is a malignant pulmonary vascular syndrome characterized by a progressive increase in pulmonary vascular resistance and pulmonary arterial pressure, which eventually leads to right heart failure and even death. Although the exact mechanism of PAH is not fully understood, pulmonary vasoconstriction, vascular remodeling, immune and inflammatory responses, and thrombosis are thought to be involved in the development and progression of PAH. In the era of non-targeted agents, PAH had a very dismal prognosis with a median survival time of only 2.8 years. With the deep understanding of the pathophysiological mechanism of PAH as well as advances in drug research, PAH-specific therapeutic drugs have developed rapidly in the past 30 years, but they primarily focus on the three classical signaling pathways, namely the endothelin pathway, nitric oxide pathway, and prostacyclin pathway. These drugs dramatically improved pulmonary hemodynamics, cardiac function, exercise tolerance, quality of life, and prognosis in PAH patients, but could only reduce pulmonary arterial pressure and right ventricular afterload to a limited extent. Current targeted agents delay the progression of PAH but cannot fundamentally reverse pulmonary vascular remodeling. Through unremitting efforts, new therapeutic drugs such as sotatercept have emerged, injecting new vitality into this field. This review comprehensively summarizes the general treatments for PAH, including inotropes and vasopressors, diuretics, anticoagulants, general vasodilators, and anemia management. Additionally, this review elaborates the pharmacological properties and recent research progress of twelve specific drugs targeting three classical signaling pathways, as well as dual-, sequential triple-, and initial triple-therapy strategies based on the aforementioned targeted agents. More crucially, the search for novel therapeutic targets for PAH has never stopped, with great progress in recent years, and this review outlines the potential PAH therapeutic agents currently in the exploratory stage to provide new directions for the treatment of PAH and improve the long-term prognosis of PAH patients.

Mass balance study of [14C]SHR0302, a selective and potent JAK1 inhibitor in humans

SHR0302, a selective JAK1 inhibitor developed by Jiangsu Hengrui Pharmaceutical Co., was intended for the treatment of rheumatoid arthritis. In this study, we evaluated the pharmacokinetics, mass balance, and metabolism of SHR0302 in six healthy Chinese male subjects after a single 8 mg (80 µCi) oral dose of [¹⁴C]SHR0302.SHR0302 was absorbed rapidly (T_max = 0.505 h), and the average t_1/2 of the SHR0302-related components in plasma was approximately 9.18 h. After an oral dose was administered, the average cumulative excretion of the radioactive components was 100.56% ± 1.51%, including 60.95% ± 11.62% in urine and 39.61% ± 10.52% in faeces.A total of 16 metabolites were identified. In plasma, the parent drug SHR0302 accounted for 90.42% of the total plasma radioactivity. In urine, SHR161279 was the main metabolite, accounting for 33.61% of the dose, whereas the parent drug SHR0302 only accounted for 5.1% of the dose. In faeces, the parent drug SHR0302 accounted for 23.73% of the dose, and SHR161279 was the significant metabolite, accounting for 5.67% of the dose. In conclusion, SHR0302-related radioactivity was mainly excreted through urine (60.95%) and secondarily through faeces (39.61%).The metabolic reaction of SHR0302 in the human body is mainly through mono-oxidation and glucuronidation. The main metabolic location of SHR0302 in the human body is the pyrrolopyrimidine ring.