Plasma Elimination Research Articles

Pharmacokinetics and ADME Profiling of Tanimilast Following an Intravenous 14C-Microtracer co-administered with an Inhaled Dose in Healthy Male Individuals.

Tanimilast is an inhaled phosphodiesterase-4 inhibitor currently in phase 3 clinical development for treating chronic obstructive pulmonary disease (COPD) and asthma. This trial aimed to characterize the pharmacokinetics, mass balance, and metabolite profiling of tanimilast. Eight healthy male volunteers received a single dose of non-radiolabeled tanimilast via powder inhaler (NEXThaler® (3200μg)), followed by a concomitant intravenous (IV) infusion of a microtracer ([14C]-tanimilast: 18.5μg and 500nCi). Plasma, whole blood, urine, and feces samples were collected up to 240 hours post-dose to quantify non-radiolabeled tanimilast, [14C]-tanimilast, and total-[14C]. The inhaled absolute bioavailability of tanimilast was found to be approximately 50%. Following IV administration of [14C]-tanimilast, plasma clearance was 22 L/h, the steady-state volume of distribution was 201 L, and the half-life was shorter compared to inhaled administration (14 vs. 39 hours, respectively), suggesting that plasma elimination is limited by the absorption rate from the lungs. 79% (71% in feces; 8% in urine) of the IV dose was recovered in excreta as total-[14C]. [14C]-tanimilast was the major radioactive compound in plasma, while no recovery was observed in urine and only 0.3% was recovered in feces, indicating predominant elimination through metabolic route. Importantly, as far as no metabolites accounting for more than 10% of the circulating drug-related exposure in plasma or the administered dose in excreta were detected, no further qualification is required according to regulatory guidelines. This study design successfully characterized the absorption, distribution, and elimination of tanimilast, providing key pharmacokinetic parameters to support its clinical development and regulatory application. Significance Statement This trial investigates PK and ADME profile of tanimilast, an inhaled PDE4 inhibitor for COPD and asthma. Eight male volunteers received a dose of non-radiolabeled tanimilast via NEXThaler® and a microtracer IV dose. Results show pivotal PK results for the characterization of tanimilast, excretion route and quantification of significant metabolites, facilitating streamlined clinical development and regulatory approval.

Lipid and Corticosteroid Biomarkers Under the Influence of Bisphosphonates.

Detecting the use of bisphosphonates (BPs) in equine athletes is of interest to regulators and laboratories due to the threat to welfare issues for the potential to provide analgesic effects and manipulating bone structure. The detection of BPs in biological matrices is challenging due to erratic biological elimination and inconsistent analytical recoveries. Therefore, complementary approaches are needed to provide evidence of their misuse in racehorses. BPs have two sub-classes: nitrogenous and non-nitrogenous. This study investigated plasma elimination following administration of one example from each sub-class, together with changes in endogenous eicosanoid and corticosteroids. Zoledronic acid (ZA) and tiludronic acid (TA) were administered by IV infusion to 8 thoroughbred horses with an 11-month washout period between each administration. Sample preparation for quantification of BPs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) utilised a two-step solid phase extraction (SPE) consisting of polymeric reversed-phase followed by weak anion exchange prior to derivatisation using trimethyl orthoacetate. Endogenous biomarkers were analysed after protein precipitation and SPE with polymeric reversed-phase prior to liquid chromatography-high resolution mass spectrometry (LC-HRMS) using data independent acquisition. The LC-MS/MS analysis showed ZA was undetectable after 8 h post-administration while TA was detected up to the final collection point of 28 days post-administration. The LC-HRMS analysis utilised targeted (i.e., prior inclusion list of compounds) approaches to monitor level changes of eicosanoid and corticosteroid biomarkers. Putative biomarkers were identified and now subject to validation for translation into routine sample analysis for improved retrospectivity to detecting BP misuse in equine plasma.

Discovery and Characterization of Brigimadlin, a Novel and Highly Potent MDM2-p53 Antagonist Suitable for Intermittent Dose Schedules.

p53 is known as the guardian of the genome and is one of the most important tumor-suppressors. It is inactivated in most tumors, either via tumor protein p53 (TP53) gene mutation or copy number amplification of key negative regulators, e.g., mouse double minute 2 (MDM2). Compounds that bind to the MDM2 protein and disrupt its interaction with p53 restore p53 tumor suppressor activity, thereby promoting cell cycle arrest and apoptosis. Previous clinical experience with MDM2-p53 protein-protein interaction antagonists (MDM2-p53 antagonists) have demonstrated that thrombocytopenia and neutropenia represent on-target dose-limiting toxicities that might restrict their therapeutic utility. Dosing less frequently, while maintaining efficacious exposure, represents an approach to mitigate toxicity and improve the therapeutic window of MDM2-p53 antagonists. However, to achieve this, a molecule possessing excellent potency and ideal pharmacokinetic properties is required. Here, we present the discovery and characterization of brigimadlin (BI 907828), a novel, investigational spiro-oxindole MDM2-p53 antagonist. Brigimadlin exhibited high bioavailability and exposure, as well as dose-linear pharmacokinetics in preclinical models. Brigimadlin treatment restored p53 activity and led to apoptosis induction in preclinical models of TP53 wild-type, MDM2-amplified cancer. Oral administration of brigimadlin in an intermittent dosing schedule induced potent tumor growth inhibition in several TP53 wild-type, MDM2-amplified xenograft models. Exploratory clinical pharmacokinetic studies (NCT03449381) showed high systemic exposure and a long plasma elimination half-life in cancer patients who received oral brigimadlin. These findings support the continued clinical evaluation of brigimadlin in patients with MDM2-amplified cancers, such as dedifferentiated liposarcoma.

Pharmacokinetics of intramuscular L-carvone in sheep.

To measure and model concentrations of the analgesic L-carvone, a natural component of spearmint, over time when administered IM to sheep and to characterize L-carvone's effects on CBCs and clinical biochemistry panels. L-carvone formulated as a 50% solution (v/v) in ethanol and propylene glycol was administered at 71.6 mg/kg IM, split between each semitendinosus muscle in 6 sheep. Venous blood was sampled over 24 hours, and plasma was separated by centrifugation. Additional blood was collected for CBC and serum biochemical analysis, and tissues were sampled after euthanasia. L-carvone concentrations in plasma and tissue homogenates were measured using HPLC-MS-MS. Plasma pharmacokinetic data were described using a nonlinear mixed effects model. Complete blood count and biochemistry data were compared to baseline values using repeated-measures ANOVA and Holm-Šidák tests (P < .05). Maximum plasma concentrations ranged from 0.28 to 1.93 µg/mL and occurred within 9 to 15 minutes after injection. Pharmacokinetics were best described using 2 compartments. Elimination half-life was 33.7 minutes and 390.2 minutes in the central and peripheral compartments, respectively. Mild increases in neutrophil count and significant increases in creatinine kinase and aspartate aminotransferase were associated with injection site myonecrosis. No physical examination, behavioral, or other clinically significant laboratory changes were noted. Intramuscular L-carvone exhibits rapid time to peak concentration, relatively slow plasma elimination, and low tissue concentrations after 24 hours. L-carvone exhibits a favorable pharmacokinetic profile for an analgesic drug. A new L-carvone formulation or administration route is needed to reduce inflammation and necrosis at the injection site.

8691 Recovery Of Adrenal Function After Stopping Mitotane In Patients With Adrenocortical Carcinoma

Abstract Disclosure: B. Altieri: None. O. Kimpel: None. F. Megerle: None. M. Detomas: None. I.O. Chifu: None. C.T. Fuss: None. M. Quinkler: None. M. Kroiss: None. M. Fassnacht: None. Background: Mitotane is the standard therapy of adrenocortical carcinoma (ACC), both adjuvantly in patients with high risk of recurrence and palliative setting, due to its relative selectivity of its cytotoxic effects towards adrenocortical cells. Therefore, it virtually always leads to adrenal insufficiency. However, frequency and characteristics of hypothalamic-pituitary-adrenal (HPA) axis recovery after discontinuation are not well defined. Methods: Retrospective study of patients with ACC adjuvantly treated with mitotane for ≥12 months who were disease-free at mitotane stop and had a minimum follow-up ≥1 year. Data on patients and tumor characteristics, mitotane treatment, and information on HPA axis were analyzed. Primary endpoint was the adrenal recovery. Explorative analysis of predictive factors (e.g. sex, age, follow-up in reference center, cumulative mitotane dose and plasma levels, duration of treatment, and dose of hydrocortisone-equivalent replacement) was performed using Cox regression. Mitotane plasma elimination rate and hormonal changes after mitotane stop were also investigated. Results: 56 patients (36 women) treated with mitotane for a median time of 25 months and an average daily dose of 2.8 g (interquartile range 1.8-3.4) were included. The average hydrocortisone-equivalent replacement daily dose during mitotane treatment was in median 49.4 mg (41.1-53.5). Mitotane plasma levels decreased slowly after discontinuation, but with a very high variability between individual patients. Median time until mitotane levels dropped below 5 mg/L, 2 mg/L, and the detection limit was 152 days (114-202), 280 days (192- 37 370), and 395 days (227-546), respectively. Full adrenal recovery was documented in 32 (57%) patients after a median time of 26 months (95%CI=19.6-32.4). Among these, 22 (69%) achieved HPA recovery within 24 months. To note, a complete recovery after more than 67 months did not occur. Partial and insufficient recovery were observed in 10 (18 %) and 14 (25%) patients, respectively. In four patients (7.1%) adrenal insufficiency persisted &amp;gt;5 years after discontinuation. Mitotane peak ≥27mg/L significantly correlated with longer time to adrenal recovery (HR=0.2, 95%CI=0.1-0.8, p=0.03). 27/38 patients (71%) followed in reference centers achieved adrenal recovery compared to only 5/18 (28%) followed-up in non-reference centers (HR=4.51, 95%CI=1.71-11.89, p=0.002). Other investigated factors were not associated with adrenal function after discontinuation. Conclusions: Our study demonstrates that adrenal recovery occurs in most patients after stopping mitotane, particularly when followed-up in specialized centers, but not in all. Elimination time of mitotane after treatment discontinuation is very long, but individually quite variable. Presentation: 6/2/2024

Acute dose-dependent effects of mescaline in a double-blind placebo-controlled study in healthy subjects

Classic psychedelics have regained interest in research and therapy. Despite the long tradition of the human use of mescaline, modern data on its dose-dependent acute effects and pharmacokinetics are lacking. Additionally, its mechanism of action has not been investigated in humans. We used a randomized, double-blind, placebo-controlled, crossover design in 16 healthy subjects (8 women) who received placebo, mescaline (100, 200, 400, and 800 mg), and 800 mg mescaline together with the serotonin 5-hydroxytryptamine-2A (5-HT2A) receptor antagonist ketanserin (40 mg) to assess subjective effects, autonomic effects, adverse effects, and pharmacokinetics up to 30 h after drug administration. Mescaline at doses >100 mg induced dose-dependent acute subjective effects. Mescaline increased systolic and diastolic blood pressure at doses >100 mg, with no difference between doses of 200-800 mg. Heart rate increased dose-dependently. Pharmacokinetics of mescaline were dose-proportional. Maximal concentrations were reached after approximately 2 h, and the plasma elimination half-life was approximately 3.5 h. The average duration of subjective effects increased from 6.4 to 14 h with increasing doses of 100-800 mg mescaline. Nausea and emesis were frequent adverse effects at the 800 mg dose. Co-administration of ketanserin attenuated and shortened acute effects of 800 mg mescaline to become comparable to the 100 and 200 mg doses. There were no ceiling effects of the subjective response within the investigated dose range, but tolerability was lower at the highest doses. These results may assist with dose finding for future research and suggest that acute effects of mescaline are primarily mediated by 5-HT2A receptors.

Pharmacokinetics and safety of topical fluralaner in koalas (Phascolarctos cinereus)

Sarcoptic mange (etiological agent Sarcoptes scabiei) is among the most important parasitic diseases of some marsupial species and has been an emerging disease of koalas, causing welfare and conservation implications. Fluralaner (Bravecto® MSD Animal Health), an ectoparasiticide of the isoxazoline class, has been demonstrated as a long-lasting and efficacious chemotherapeutic agent against sarcoptic mange in multiple mammal species and may also be beneficial for impacted koalas. Here, we evaluated the pharmacokinetics and clinical safety of fluralaner in koalas. Healthy captive individuals were treated topically with 85 mg/kg fluralaner administered to the interscapular epidermis. Following treatment, fluralaner was detected in plasma using ultra-performance liquid chromatography and tandem mass-spectrometry over a 12-week period. The mean maximum plasma concentration (Cmax) was 66.4 ng/mL; mean time was Cmax of 2.71 days; plasma elimination half-life (T1/2) was 30.91 days; and mean residence time (MRT) was 27.38 days. Haematological, blood biochemical, animal husbandry and clinical observations, over the same time period, demonstrated fluralaner was well tolerated. Overall, this research suggests fluralaner is a safe and long-lasting chemotherapeutic agent that may be efficacious against S. scabiei in koalas. Further research focussed on quantifying efficacy in captive and field settings, and across a range of disease severities would be valuable.

Acute effects of R-MDMA, S-MDMA, and racemic MDMA in a randomized double-blind cross-over trial in healthy participants.

Racemic 3,4-methylenedioxymethamphetamine (MDMA) acutely increases mood, feelings of empathy, trust, and closeness to others and is investigated to assist psychotherapy. Preclinical research indicates that S-MDMA releases monoamines and oxytocin more potently than R-MDMA, whereas R-MDMA more potently stimulates serotonin 5-hydroxytryptamine-2A receptors. S-MDMA may have more stimulant properties, and R-MDMA may be more psychedelic-like. However, acute effects of S- and R-MDMA have not been examined in a controlled human study. We used a double-blind, randomized, placebo-controlled, crossover design to compare acute effects of MDMA (125 mg), S-MDMA (125 mg), R-MDMA (125 mg and 250 mg), and placebo in 24 healthy participants. Outcome measures included subjective, autonomic, and adverse effects, pharmacokinetics, and plasma oxytocin, prolactin, and cortisol concentrations. S-MDMA (125 mg) induced greater subjective effects ("stimulation," "drug high," "happy," "open") and higher increases in blood pressure than R-MDMA (both 125 and 250 mg) and MDMA (125 mg). Unexpectedly, R-MDMA did not produce more psychedelic-like effects than S-MDMA. S-MDMA increased plasma prolactin more than MDMA, and S-MDMA increased plasma cortisol and oxytocin more than MDMA and R-MDMA. The plasma elimination half-life of S-MDMA was 4.1 h after administration. The half-life of R-MDMA was 12 and 14 h after the administration of 125 and 250 mg, respectively. Half-lives for S-MDMA and R-MDMA were 5.1 h and 11 h, respectively, after racemic MDMA administration. Concentrations of the CYP2D6-formed MDMA-metabolite 4-hydroxy-3-methoxymethamphetamine were lower after R-MDMA administration compared with S-MDMA administration. The pharmacokinetic findings are consistent with the R-MDMA-mediated inhibition of CYP2D6. Stronger stimulant-like effects of S-MDMA in the present study may reflect the higher potency of S-MDMA rather than qualitative differences between S-MDMA and R-MDMA. Equivalent acute effects of S-MDMA, MDMA, and R-MDMA can be expected at doses of 100, 125, and 300 mg, respectively, and need to be investigated.Trial registration: ClinicalTrials.gov identifier: NCT05277636.

Tramadol intoxication in children: An emerging issue

Background: Prescribing tramadol in children raises safety concerns. In Europe, tramadol is still approved and licensed for use in children over 1-3 years of age, depending on the country. In this context, the authors report a case of a tramadol overdose in a 5-year-old-child with a medical history of homozygous sickle cell disease.Methods: Tramadol and M1 were quantified using liquid chromatography with a diode array detection method. CYP2D6 genotype was determined using a Next Generation Sequencing platform (MISeq, Illumina).Results: Tramadol and M1 were quantified in blood respectively at 5.48 and 1.32 µg/mL at admission, at 0.77 and 0.35 µg/mL 12 hours later, and at 0.32 and 0.18 µg/mL 20 hours later. The patient was predicted as a CYP2D6 normal metabolizer (*35/*29).Conclusion: One of the most important difficulties with the use of tramadol in children relates to its pharmacokinetic (PK) properties. Indeed, tramadol’s PK is characterized by a great variability related to: i) anatomical/physiological factors that impact the volume of distribution (Vd); ii) CYP2D6 genetic polymorphisms. Considering such an issue is particularly relevant to prevent poisoning. In the reported case, the plasma elimination half-life was estimated at 6.3 h, significantly more than those reported in 2-8 year-old children (about 3 h). This discrepancy does not seem related to genetic polymorphisms but rather to the Vd. Indeed, the patient was predicted to be a CYP2D6 normal metabolizer (*35/*29). The case presented here highlights the risk associated with the tramadol use in children and emphasizes the importance of considering PK variability among this population. Such variability necessitates greater caution in prescribing tramadol in children and highlights the importance of therapeutic education for families of children treated with this painkiller.

Diltiazem Hydrochloride Floating Matrix Tablet: Formulation and in vitro-in vivo Evaluation.

Diltiazem hydrochloride is a calcium channel-blocker with a plasma elimination half-life of 4.4 ± 1.3 h and has a narrow absorption window. So, this work aimed to prepare a gastro-retentive floating matrix tablet. The direct compression method was used to manufacture tablets. 32 factorial design was applied for optimization, taking Hydroxypropyl Methylcellulose K100M (HPMC K 100M) and the amount of sodium bicarbonate as independent factors and cumulative percentage release at 1 h, at 6 h, and at 12 h and floating lag time as dependent variables. The high amount of HPMC K100M and sodium bicarbonate shows good results. The optimized preparation was evaluated for differential scanning calorimetry, in-vivo gastric retention in male albino rabbits, kinetic modeling, and stability study. An in vivo study revealed gastric retention of tablets up to 6 h in healthy male Albino rabbits. The stability study indicated no significant change in the buoyancy and release profiles of the drug. From this study, it can be concluded that the gastro-retentive diltiazem hydrochloride floating matrix tablet was successfully prepared and retained inside the rabbit stomach for up to 6 h and was stable under accelerated stability study.

OSMOTIC DRUG DELIVERY SYSTEM OF NICORANDIL: DESIGN AND EVALUATION

Objective: The purpose of the current research was to design a nicorandil formulation with controlled drug release using the principles of osmotic pump technology. Nicorandil is a biopharmaceutical classification system (BCS) class 3 drug, having a shorter plasma elimination half-life and bioavailability of 75 to 80%. Methods: The elementary osmotic pump (EOP) was prepared by coating a cellulose acetate polymer on the prepared core tablet. A 24-factorial design was applied to optimize the parameters for the osmotic tablet. A surface orifice was drilled. Results: Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD) results showed that there was no interaction between drugs and excipients. A 24-factorial design was applied to optimize the parameters for the elementary osmotic pump. The optimized batch was characterized for in vitro drug release studies, and the effects of pH, osmotic pressure, and agitation intensity were analyzed. All the batches showed a drug release ranging from 90.48% to 98.78% after 12 hours. There was no change in the drug release pattern at different pHs and agitation intensities. The drug release was found to decrease with the increasing osmotic pressure of the dissolution medium. The results showed that the amounts of sodium chloride and mannitol were positively affecting the drug release, while the plasticizers PEG400 and DBP were not critical. Scanning electron microscopic studies (SEM) showed the integrity and surface morphology of the coating membrane before and after dissolution. The prepared EOP was found to deliver nicorandil at zero-order for up to 12 hours. Conclusion: Nicorandil was developed successfully as a controlled drug delivery during a 12-hour period, with variables optimized by the use of a 24-factorial design.

Preclinical development of EXT608, an investigational parathyroid hormone derivative with extended half-life for the treatment of hypoparathyroidism.

Hypoparathyroidism, a deficiency of parathyroid hormone (PTH), results in hypocalcemia, hyperphosphatemia, and hypercalciuria. The disease is poorly controlled by calcium and vitamin D supplements or native PTH(1-84) replacement therapy. A version of PTH is being developed using D-VITylation technology, whereby vitamin D is conjugated to a therapeutic peptide, which confers a long plasma half-life by virtue of binding to the abundant vitamin D binding protein (DBP). D-VITylation of PTH caused no reduction in activity at the PTHR1 receptor, and resulted in a plasma elimination half-life of 7-15h in rats and 24-32h in cynomolgus monkeys. Analysis of steady-state pharmacokinetics as a function of dose showed flat profiles with smaller peak:trough ratios at low doses, indicative of slower subcutaneous absorption. In thyroparathyroidectomized (TPTx) rats, PTH(1-34)-vitamin D conjugates restored serum calcium and phosphate levels into the normal range over the 24h dosing period, and increased bone turnover markers and reduced bone mineral density. Urinary calcium was initially elevated, but normalized by the end of treatment on day 27. In healthy monkeys, a single dose of PTH(1-34)-vitamin D conjugates elevated serum calcium levels above the normal range for a period of 24-48h while simultaneously reducing urinary calcium. Therefore, the lead compound, EXT608, is a promising candidate as a therapeutic that can truly mimic the endogenous activity of PTH and warrants further study in patients with hypoparathyroidism.

Modified Release of Acetaminophen from Matrix Tablet Formulations: Influence of Tablet Geometry

Background: Acetaminophen (APAP) or paracetamol is a widely used over-the-counter, analgesic (common conditions treated include headaches, backache, toothache, muscle aches, arthritis, sore throat etc.) and antipyretic drug. It can be administered orally, in the form of a tablet (plain, effervescent, orodispersable, etc.) or liquid, rectally in the form of a suppository or by injection (intravenously or intramuscularly). It is well absorbed orally with a plasma elimination half-life ranging from 1 to 4 h. The modified release oral formulation can prolong its therapeutic effects by maintaining APAP average plasma concentrations. Objective: In the context of this work, two APAP formulation tablets with different geometries were produced from standard pharmaceutical excipients to investigate the role of altered tablet geometry in modified oral drug delivery. Methods: APAP tablets were prepared by direct compression, using hydroxypropyl methylcellulose (HPMC K15M), polyvinylpyrrolidone (PVP, MW: 55,000) and magnesium stearate, as ingredients. The release profiles were probed in aqueous dissolution media (pH 1.2 and 6.8) to simulate the conditions in the gastrointestinal tract in a United States Pharmacopeia (USP) dissolution paddle apparatus II and analyzed using an ultraviolet (UV) spectrophotometer (λmax = 244 nm). Results: The results indicated that the tablets were within the acceptable range of all evaluation parameters (tablet dimensions, drug content, weight variation, and breaking force) as defined by the international standards stated in the US Pharmacopoeia. The dissolution results showed that the APAP’s release profile was controlled by the tablets’ different geometries and, specifically the surface area (SA) and the surface area/volume (SA/V) ratio of the different tablets. The tablets with smaller SA/V ratios and SA showed slower drug release, indicative of a modified release motif. Conclusion: Altered tablet geometry plays an important role in APAP-modified oral drug delivery.

Pharmacokinetic and safety profiles of mesalazine enema in healthy Chinese subjects: A single- and multiple-dose study.

Mesalazine is a well-established treatment for ulcerative colitis by oral or topical administration. However, the pharmacokinetic (PK) and safety profiles of mesalazine administered by an enema has not been clarified in Chinese population. We conducted an open-label study to assess the PK and safety profiles of mesalazine in 11 healthy Chinese subjects after receiving mesalazine enema (1 g/100 mL) once daily for 7 consecutive days. Blood and urine samples were collected for assay of mesalazine and N-acetyl mesalazine by liquid chromatography-tandem mass spectrometry. The PK and safety data were summarized using descriptive statistics. The mean (standard deviation) maximum plasma concentration (Cmax), area under plasma drug concentration-time curve from time 0 to the last measurable plasma concentration time point (AUC0-t) and elimination half-life (t1/2) of mesalazine were 1007.64 (369.00) ng/mL, 9608.59 (3533.08) h·ng/mL and 3.33 (1.99) h, respectively after the first dose administration. In multiple-dose study, the estimated accumulation factor of mesalazine was 1.09. The cumulative urinary excretion rate of parent and major metabolite of mesalazine was 27.77%. After the last doe administration, 2.21% of the administered dose was excreted as mesalazine and 24.47% as N-acetyl mesalazine in urine within 24 h. Overall, 9 adverse events (AEs) were reported in 4 of the 11 subjects (36.4%), including oral ulcer, toothache, upper respiratory tract infection (1 each) and laboratory abnormalities (6 cases). All AEs were mild and recovered spontaneously without treatment, and were not considered as related to mesalazine. Mesalazine enema (1 g/100 mL) was safe and well tolerated in healthy Chinese subjects. These findings support further clinical trials in Chinese patients. Trial registration: This trial was registered to Chinese Clinical Trial Registry (ChiCTR) at https://www.chictr.org.cn (registration number: ChiCTR2300073148).

Pharmacokinetics of four tannin compounds from Sanguisorba officinalis L. before and after processing by ultra-high-performance liquid chromatography-tandem mass spectrometry.

Sanguisorba officinalis L. possesses detoxifying, analgesic, and hemostatic properties. After charred processing, S. officinalis exhibits significantly enhanced medicinal effects. Currently, most pharmacokinetic studies focus on the chemical constituents of unprocessed S. officinalis. There is limited research on the comparison of chemical constituents before and after processing. This study established a pharmacokinetic method using ultra-high-performance liquid chromatography-tandem mass spectroscopy (UHPLC-MS/MS) to simultaneously determine the levels of four tannin compounds in rat plasma. In negative ion mode, MS/MS detection was performed using an electrospray ionization source. Chromatographic separation was performed using WATERS ACQUITY HSS T3 column (2.1 × 100mm, 1.8µm) with a gradient elution of water and acetonitrile as the mobile phase. The pharmacokinetic results indicate that all four compounds reached peak concentrations within 2h, demonstrating rapid absorption into the bloodstream within the gastrointestinal tract. Notably, the absorption was generally faster in the charred compound of S. officinalis after processing. These four compounds exhibited slower elimination in rat plasma, while in S. officinalis charcoal, the compounds were eliminated more rapidly. The pharmacokinetic results have revealed the pharmacokinetic characteristics of the four analytes in rat plasma which provides valuable reference information for further investigating the in vivo absorption process of S. officinalis after processing.

First-in-Human Safety, Tolerability, and Pharmacokinetics of Single-Dose Kukoamine B Mesylate in Healthy Subjects: A Randomized, Double-Blind, Placebo-Controlled Phase I Study.

Kukoamine B mesylate (KB) is a mesylate chrysamine B targeting lipopolysaccharides and CpG DNA, two potential treatment targets in sepsis. This first-in-human, randomized, double-blind, placebo-controlled, phase I study was conducted from July 2014 to May 2015 to explore the safety, tolerability, and pharmacokinetics of KB in healthy subjects. This study consisted of a pre-phase (four participants; KB at 0.005mg/kg) and a dose escalation phase (eight participants/dose group, randomized 6:2 to KB or placebo; KB at 0.02, 0.04, 0.08, 0.12, 0.24, and 0.48mg/kg). The primary endpoint was safety. Fifty-two participants were enrolled, including four in the pre-phase and 48 in the dose escalation phase. Among the 40 participants who received KB, 12 (30.0%) experienced adverse events (AEs), while two (16.7%) experienced AEs among 12 participants who received the placebo. The most common AEs in the KB group were headache (5.0%), influenza (5.0%) and positive white blood cell in urine (5.0%). After the administration of KB, the mean plasma elimination half was around 1.61-4.24h. The relationship between the KB plasma exposure of KB and the administered dose was not linear. The percentage of cumulative urinary excretion of KB was similar among the different dose groups (21.7-35.2%) and the urinary excretion of KB decreased significantly about 8h after administration. Single-dose KB demonstrated favorable safety and tolerability in healthy subjects at the dose level of 0.005-0.48mg/kg. KB exhibited a non-linear pharmacokinetic profile with a half-life of about 1.61-4.24h, which mainly distributed in plasma. ClinicalTrials.gov identifier, NCT02219971.

Recovery of adrenal function after stopping mitotane in patients with adrenocortical carcinoma.

Mitotane is the standard therapy of adrenocortical carcinoma (ACC) due to its relative selectivity of its cytotoxic effects toward adrenocortical cells. Therefore, it virtually always leads to adrenal insufficiency. Frequency and characteristics of hypothalamic-pituitary-adrenal axis recovery after discontinuation are ill-defined. This was a retrospective study of patients with ACC adjuvantly treated with mitotane for ≥12 months who were disease-free at mitotane stop and had a minimum follow-up ≥1 year. Primary endpoint was adrenal recovery. Cox regression analyses were used to identify predictive factors. Moreover, mitotane plasma elimination rate and hormonal changes after mitotane stop were investigated. Fifty-six patients (36 women) treated with mitotane for a median time of 25 months and an average daily dose of 2.8 g were included. Median time after discontinuation until mitotane levels dropped below 5 and 2 mg/L, and the detection limit was 152 days (interquartile range: 114-202), 280 days (192-370), and 395 days (227-546), respectively. Full adrenal recovery was documented in 32 (57%) patients after a median time of 26 months (95% confidence interval [CI] = 19.6-32.4). In 4 patients (7.1%), adrenal insufficiency persisted >5 years after discontinuation. Mitotane peak ≥ 27 mg/L significantly correlated with longer time to adrenal recovery (hazard ratio [HR] = 0.2, 95% CI = 0.1-0.8, P = .03). Twenty-seven of 38 patients (71%) followed in reference centers achieved adrenal recovery compared with only 5/18 (28%) followed up in non-reference centers (HR = 4.51, 95% CI = 1.71-11.89, P = .002). Other investigated factors were not associated with adrenal function after discontinuation. Our study demonstrates that adrenal recovery occurs in most patients after stopping mitotane, particularly when followed up in specialized centers, but not in all. Elimination time of mitotane after treatment discontinuation is very long but individually quite variable.

Development and validation of UV–Vis spectrophotometry-colorimetric method for the specific quantification of rivastigmine tartrate from separable effervescent microneedles: Ex vivo and in vivo applications in complex biological matrices

Rivastigmine Tartrate is an acetylcholinesterase inhibitor commonly used in Alzheimer treatment. Due to its hydrophilicity, short plasma elimination half-time, and poor blood-brain barrier penetration, developing a new drug delivery system for RT administration is essential. Accordingly, microneedles offer several advantages and could be a promising drug delivery system for RT administration. One of those types of MNs with numerous advantages is separable-effervescent microneedles. To support the formulation development, an analytical method using UV–Vis spectrophotometry was validated in phosphate buffered saline media and various biological matrices, such as rat skin, brain, and plasma to measure the amount of RT in the SEMNs preparations. The developed analytical method was validated under ICH guidelines. The results showed that the instrument could specifically detect the RT in the preparations without being interfered with by other compounds. The calibration curves in various biological matrices were linear ≥ 0.9985. The LOD and LLOQ values of the PBS media biological matrices were found to be 1.5 and 4.8 µg/mL, 1.2 and 3.7 µg/mL, 0.42 and 1.27 µg/mL, and 0.38 and 1.16 µg/mL, respectively. All the accuracy and precision values of this developed method were within acceptable ranges. Additionally, the extraction recovery was prominent after undergoing the protein precipitation process. As a result, the analytical method was proven to be valid and was successfully applied to quantify the amount of RT in the SEMNs formulation, in vitro and ex vivo permeation, along with in vivo pharmacokinetic studies.

Filtration and tubular handling of EWE-hC3Nb1, a complement inhibitor nanobody, in wild type mice and a mouse model of proteinuric kidney disease.

Tubular activation and deposition of filtered complement proteins have been implicated in the progression of proteinuric kidney disease. The potent C3b-specific nanobody inhibitor of the alternative pathway, EWE-hC3Nb1, is likely freely filtered in the glomerulus to allow complement inhibition in the tubular lumen and may provide a novel treatment option to prevent tubulointerstitial injury. However, more information on the pharmacokinetic properties and renal tubular handling of EWE-hC3Nb1 nanobody is required for its pharmacological application in relation to kidney disease. Here, we examined the pharmacokinetic properties of free EWE-hC3Nb1 in mouse plasma and urine, following subcutaneous injection in wild-type control and podocin knock out (KO) mice with severe proteinuria. Tubular handling of filtered EWE-hC3Nb1 was assessed by immunohistochemistry (IHC) on kidney tissue from control, proteinuric mice, and KO mice deficient in the proximal tubule endocytic receptor megalin. Rapid plasma absorption and elimination of EWE-hC3Nb1 was observed in both control and proteinuric mice; however, urinary excretion of EWE-hC3Nb1 was markedly increased in proteinuric mice. Urinary EWE-hC3Nb1 excretion was amplified in megalin KO mice, and substantial accumulation of EWE-hC3Nb1 was observed in megalin-expressing renal proximal tubules by IHC. Moreover, free EWE-hC3Nb1 was found to be rapidly cleared from plasma. In conclusion, filtered EWE-hC3Nb1 is reabsorbed by a megalin-dependent process in the proximal tubules. Increased load of filtered proteins in the tubular fluid may inhibit the megalin-dependent uptake of EWE-hC3Nb1 in proteinuric mice. Treatment with EWE-hC3Nb1 may allow investigation of the effects of complement inhibition in the tubular fluid.

Analysis on dynamic changes of etizolam and its metabolites and exploration of its development prospect using UPLC-Q-exactive-MS

As one of the most widely abused designer benzodiazepines in the world, etizolam has been found in many cases in many countries. In this study, UPLC-Q-Exactive-MS was used for the first time to establish a dynamic change model of etizolam and its metabolites in rats. Compared with previous studies, the detection sensitivity and reproducibility of the instrument were higher. In the experiment, we optimized the traditional pharmacokinetic model based on Gauss function. According to the significant difference of etizolam in the plasma elimination phase of rats, a new pharmacokinetic model based on Lorentz function was established to describe the dynamic changes of etizolam more rigorously, which made the error effects lower and the accuracy of the pharmacokinetic parameters was improved. At the same time, the pharmacokinetic parameters of etizolam were compared with four other designer benzodiazepines reported in previous studies in rats, and we found the direct reason for the popularity of etizolam in the NPS market and explored the future development of etizolam for the first time. In addition, 21 metabolites were found through rat experiments to effectively detect etizolam abuse for a long time, of which 4 metabolites had the longest detection window and could be used as long-acting metabolites for experiments, which greatly prolongs the detection window and extends the time range in which etizolam was detected in real cases. This study is the first to conduct a systematic and comprehensive study on the metabolism and pharmacokinetics of etizolam and find out the direct reason for the prevalence of etizolam abuse, and we also discuss the development trend of etizolam in the future market of new psychoactive substances, which is beneficial for forensic experts to assess the trend of drug abuse and can provide reference for relevant drug control and drug treatment.