Concentrations Of Active Metabolite Research Articles

Dose-exposure-response of CARDALIS® (benazepril/spironolactone) on the classical and alternative arms of the renin-angiotensin-aldosterone system in healthy dogs.

Benazepril exhibits a dose-dependent effect on biomarkers of the circulating renin-angiotensin-aldosterone system (RAAS) in dogs. To characterize the dose-exposure-response relationship of a fixed-dose combination product including benazepril and spironolactone (CARDALIS®) on RAAS biomarkers in dogs. Eighteen purpose-bred healthy beagle dogs. Three groups of 6 dogs received different doses of CARDALIS® for 14 days following induction of RAAS activation by feeding a low-sodium diet: (a) benazepril 0.25 mg/kg + spironolactone 2 mg/kg PO q24h (label dose); (b) benazepril 0.25 mg/kg + spironolactone 2 mg/kg PO q12h; or (c) benazepril 0.5 mg/kg + spironolactone 4 mg/kg PO q12h. Blood samples were collected at baseline and serial time intervals after CARDALIS® dosing to measure serum RAAS biomarkers and plasma concentrations of active drug metabolites. Time-weighted averages for serum RAAS biomarkers after CARDALIS® dosing at steady state were compared between dosage groups using Wilcoxon rank-sum testing. Compared to the label dose, the highest dose of CARDALIS® was associated with a 30% decrease in angiotensin II (P = .03), 94% increase in angiotensin 1-7 (P = .03), 71% decrease in surrogate activity of ACE (P = .002), and 116% increase in circulating aldosterone (P = .02). CARDALIS® was well-tolerated at all doses with no clinically relevant changes in renal values or serum electrolytes. The combined CARDALIS® product leads to dose-dependent alterations of RAAS metabolites. These results could help inform clinical trials in dogs with heart disease.

The effect of concurrent clopidogrel and omeprazole administration on clopidogrel metabolism and platelet function in healthy cats.

Some studies in humans show that the concurrent use of clopidogrel and omeprazole decreases plasma clopidogrel active metabolite (CAM) concentrations and clopidogrel antiplatelet effects. Whether this drug interaction occurs in cats is unknown. We hypothesized that administration of clopidogrel with omeprazole would decrease plasma CAM concentrations and decrease clopidogrel antiplatelet effects in healthy cats. Ten domestic cats. In this 2-sequence, 2-period, 2-treatment randomized crossover study, healthy cats were randomly assigned to receive clopidogrel only (18.75 mg PO q24h) or clopidogrel with omeprazole (1 mg/kg PO q12h) for 10 days, followed by a 2-week washout period, and then the opposite treatment for another 10 days. Blood was collected by jugular venipuncture on days 0, 5, and 10. Plasma CAM concentrations were measured using high-performance liquid chromatography-tandem mass spectrometry. Platelet function was evaluated using Plateletworks, Multiplate Analyzer, and Platelet Function Analyzer-100 (PFA-100). Multiplate Analyzer and PFA-100 detected no difference in platelet function between days or treatment groups. Plateletworks detected a significant difference (P < .001) in platelet function from day 0 to 5 and day 0 to 10 in both treatment groups but no difference between treatment groups. Plasma CAM concentrations were significantly lower on day 10 (P < .02) in cats receiving both medications versus clopidogrel only. Concurrent omeprazole and clopidogrel administration was associated with altered pharmacokinetics on day 10, but no difference in pharmacodynamics between the 2 treatment groups. The short-term use of clopidogrel and omeprazole does not seem to alter platelet function significantly.

Multiple-Dose Pharmacokinetics and Safety of Mitragynine, the Major Alkaloid of Kratom, in Rats.

This study reports the steady-state pharmacokinetic parameters for mitragynine and characterizes its elimination in male and female rats. Four male and female rats were dosed q12h with 40 mg/kg, and orally administered mitragynine for 5 and 6 days, respectively. Using a validated ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method, the plasma concentrations of mitragynine, its metabolites (7-hydroxymitragynine, 9-hydroxycorynantheidine, and mitragynine acid), and a non-CYP oxidation product (3-dehydromitragynine) were determined at various time points. Sex differences in pharmacokinetics were observed, with females demonstrating significantly higher systemic exposure of mitragynine than males. The mitragynine area under the curve normalized by the dose interval (AUC/τ) was 6741.6 ± 869.5 h*ng/mL in female rats and 1808.9 ± 191.3 h*ng/mL in males (p < 0.05). Both sexes produced similar metabolite profiles; the major metabolites were mitragynine acid and 9-hydroxycorynantheidine. 7-Hydroxymitragynine was a minor metabolite. However, higher exposure (AUCs) and the maximum plasma concentrations (C max) of active metabolites, 7-hydroxymitragynine and 9-hydroxycorynantheidine, were observed in female rats and exhibited substantial sex differences. Renal clearance of mitragynine (CLr) was low (0.64 ± 0.3 mL/h in males and 0.98 ± 0.4 mL/h in females), and unchanged mitragynine accounted for <1% of the dose excreted in feces (both sexes). The clinical chemistry, complete blood count, and hematological test results reported no abnormal hematological findings after multiple dosing in either sex.

The concentration of maternal sacubitril/valsartan transferred into human milk is negligible.

Peripartum cardiomyopathy (PPCM) is a common cause of heart failure (HF) in the peripartum. Some medications are considered safe while breastfeeding. However, sacubitril/valsartan (Entresto), while efficacious, is not recommended in breastfeeding women due to concerns about adverse infant development, and no published data suggest otherwise. This study aimed to assess the transfer of sacubitril/valsartan into human milk and evaluate the infant's risk of drug exposure. The InfantRisk Human Milk Biorepository released samples and corresponding health information from five breastfeeding maternal-infant dyads exposed to sacubitril/valsartan. Sacubitril, valsartan, and LBQ657 (sacubitril active metabolite) concentrations were determined using liquid chromatography-mass spectrometry (LC/MS/MS) from timed samples 0, 1, 2, 4, 6, 8, 10, and 12 h following medication administration at steady state conditions. Valsartan levels were below the detection limit of 0.19 ng/mL in all milk samples. Sacubitril was measurable in all milk samples of the five participants, peaking 1 h after drug administration at a mean concentration of 1.52 ng/mL for a total infant dose of 0.00049 mg/kg/12 h and a relative infant dose (RID) calculated at 0.01%. The maximum concentration of its active metabolite LBQ657 in the milk samples was observed 4 h after medication administration and declined over the remaining 12-h dosing interval, for an average concentration of 9.5 ng/mL. The total infant dose was 0.00071 mg/kg/12 h, and the RID was 0.22%. Two mothers reported continuing to breastfeed while taking sacubitril/valsartan; both mothers stated observing no negative effects in their breastfed infants. The transfer of sacubitril/valsartan into human milk is minimal. These concentrations are unlikely to pose a significant risk to breastfeeding infants, with a combined calculated RID of <0.25%, which is far lower than the industry safety standards (RID <10%).

Tailoring therapeutics via a systematic beneficial elements comparison between photosynthetic bacteria-derived OMVs and extruded nanovesicles

Photosynthetic bacteria (PSB) has shown significant potential as a drug or drug delivery system owing to their photothermal capabilities and antioxidant properties. Nevertheless, the actualization of their potential is impeded by inherent constraints, including their considerable size, heightened immunogenicity and compromised biosafety. Conquering these obstacles and pursuing more effective solutions remains a top priority. Similar to extracellular vesicles, bacterial outer membrane vesicles (OMVs) have demonstrated a great potential in biomedical applications. OMVs from PSB encapsulate a rich array of bioactive constituents, including proteins, nucleic acids, and lipids inherited from their parent cells. Consequently, they emerge as a promising and practical alternative. Unfortunately, OMVs have suffered from low yield and inconsistent particle sizes. In response, bacteria-derived nanovesicles (BNVs), created through controlled extrusion, adeptly overcome the challenges associated with OMVs. However, the differences, both in composition and subsequent biological effects, between OMVs and BNVs remain enigmatic. In a groundbreaking endeavor, our study meticulously cultivates PSB-derived OMVs and BNVs, dissecting their nuances. Despite minimal differences in morphology and size between PSB-derived OMVs and BNVs, the latter contains a higher concentration of active ingredients and metabolites. Particularly noteworthy is the elevated levels of lysophosphatidylcholine (LPC) found in BNVs, known for its ability to enhance cell proliferation and initiate downstream signaling pathways that promote angiogenesis and epithelialization. Importantly, our results indicate that BNVs can accelerate wound closure more effectively by orchestrating a harmonious balance of cell proliferation and migration within NIH-3T3 cells, while also activating the EGFR/AKT/PI3K pathway. In contrast, OMVs have a pronounced aptitude in anti-cancer efforts, driving macrophages toward the M1 phenotype and promoting the release of inflammatory cytokines. Thus, our findings not only provide a promising methodological framework but also establish a definitive criterion for discerning the optimal application of OMVs and BNVs in addressing a wide range of medical conditions.

Transient Decrease in Sperm Motility after Plateletpheresis

AbstractAlthough people are constantly exposed to phthalates little is known about the extent to which PAEs affect sperm. Most studies do not address changes at the single-cell level. Our study concentrated on the examination of donors who were assumed to have been exposed to high levels of phthalate under plateletpheresis. We used Computer-Assisted-Sperm-Analysis to study the association between the most potent phthalate, di-2-ethylhexyl phthalate, and a decrease in sperm motility. In an exploratory in vivo study, we investigated whether plateletpheresis of donors led to an increase in the concentration of active metabolites of DEHP in seminal plasma and whether this had an effect on sperm motility. PAE metabolites and sperm motility parameters of ejaculate donors were analyzed at a single-cell level before and after plateletpheresis. We found an increase in PAE metabolite concentration in the seminal plasma, associated with a decrease in flagellar beat frequency after plateletpheresis. Follow-up analysis showed that this was a transient effect of plateletpheresis in terms of a PAE concentration increase in seminal plasma and a decrease in sperm motility. This study shows that plateletpheresis results in high levels of phthalate exposure and that these are associated with a transient and reversible decrease in sperm motility.

Anticancer activity, phytochemical investigation and molecular docking insights of Citrullus colocynthis (L.) fruits

Cancer disease is regarded as one of the most significant public health issues, regardless of economic standards. Medicinal plants are now regarded as a natural source of anticancer medicines due to their antioxidant and anti-mutagenic actions. Cucurbitaceae is considered to be one of the most economically significant families. One family species is Citrullus colocynthis (L.), which has a high concentration of many active secondary chemical metabolites. Various C. colocynthis plant extracts showed cytotoxicity against some cancer cells. This study aims to identify the C. colocynthis fruit components and determine whether they have anticancer action against MIA PaCa-2 and A431 cells. High-Performance Liquid Chromatography/Quadrupole Time of Flight/Mass Spectrometry (HPLC/QTOF/MS); the technique was accustomed to investigate the compounds of the ethyl acetate (EtOAc) fruit extract. Anticancer activity was investigated on both MIAPaCa-2 and A-431 cell lines. DPPH assay for antioxidant activity was carried out. Molecular modelling was employed to help understand the molecular basis for the observed anticancer activity. 24 compounds were tentatively identified by comparing the extract’s fragmentation pattern in positive mode against reference compounds spectra and literature. The EtOAc extract of C. colocynthis had effective positive results on cancer cells (MIAPaCa-2 and A-431) and was characterized by slight or no harmful effect on normal (healthy) cells. For the DPPH assay, EtOAc and BuOH extracts exhibited high antioxidant activity (86 and 76%, respectively) compared with the oxidative potential of the standard compound (Caffeic acid, 98%). One of the major cucurbitacin derivatives that LC/MS tentatively identified in the EtOAc extract was Cucurbita-5(10),6,23-triene-3β,25-diol. During this study, docking experiments and MD simulations were carried out, which suggested the anti-pancreatic cancer activity of C. colocynthis extract to be attributed to EGFR inhibition by Cucurbita-5(10),6,23-triene-3β,25-diol. Therefore, expansion of this type of research should be encouraged in the hope of obtaining natural therapeutics for cancerous tumors in the future, having the advantage of being cheaper, safer, and with fewer side effects.

Evaluation of the effect of CYP2D6*3, *4,*10, and *17 polymorphisms on the pharmacokinetic of tamoxifen and its metabolites in patients with hormone-positive breast cancer

Background and objectiveA high rate of interindividual variability in response to tamoxifen (TAM) in breast cancer patients with CYP2D6 polymorphism has been reported, which affects the patient’s therapeutic outcome. The objective of this study was to investigate the pharmacogenomics of CYP2D6 genotyping in Iranian patients with breast cancer treated with adjuvant TAM. MethodsA peripheral blood sample was obtained to determine the steady-state plasma concentrations of TAM and its metabolites (Endoxifen (EN) and 4-Hydroxytamoxifen (4-OHT)) using high-performance liquid chromatography with fluorescence detection (HPLC-FLU) assay. We detected CYP2D6 * 3, * 4, * 10, and * 17 single nucleotide polymorphisms via polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. ResultsA total of 84 Iranian estrogen receptor‑positive breast cancer patients receiving the daily dose of 20 mg tamoxifen were recruited. Although a consequent decrease in the median EN and 4-OHT concentrations was observed by comparing poor or intermediate metabolizer patients with an extensive metabolizer population, this difference did not reach a significant level. The mean plasma EN concentrations in poor and intermediate metabolizers were 46.1% (95% CI, 7.4–27.8%) and 59.4% (95% CI, 11.9–37.3%) of extensive metabolizer subjects, respectively. Poor and intermediate metabolizers had the mean plasma 4-OHT concentrations that were 46.6% (95% CI, 0.9–61.7%) and 73.2% (95% CI, 2.7–93.1%) of those of subjects who were extensive metabolizer, respectively. ConclusionsThe possible role of genotyping in Iranian patients' response to treatment may explain inter-individual differences in the plasma concentrations of active metabolites of TAM.

Modeling population pharmacokinetics of morniflumate in healthy Korean men: extending pharmacometrics analysis to niflumic acid, its major active metabolite.

This study aimed to quantify and explain inter-subject variability in morniflumate pharmacokinetics and identify effective covariates through population pharmacokinetics modeling. Models were constructed using bioequivalence pharmacokinetics results from healthy Korean males and individual physiological and biochemical parameters. Additionally, we incorporated previously reported pharmacokinetics results of niflumic acid, a major active metabolite of morniflumate, to extend the established population pharmacokinetics model and predict niflumic acid pharmacokinetics. Moreover, we used quantitative reports of leukotriene B4 (LTB4) synthesis inhibition in response to niflumic acid exposure to predict drug efficacy using Sigmoid Emax model. Population pharmacokinetics profiles of morniflumate were described using a multi-absorption (5-sequential) two-compartment model, and analysis of inter-individual variability suggested that volume of distribution in peripheral compartment was correlated with body mass index (BMI). Model simulation results showed that individuals with lower BMI had higher plasma concentrations of morniflumate and niflumic acid, resulting in increased and sustained inhibition of LTB4 synthesis. Under steady-state conditions, average plasma concentrations of morniflumate and niflumic acid were 2.66-2.68 times higher in group with a BMI of 17.36kg/m2 compared to the group with a BMI of 28.41kg/m2. Additionally, inhibition of LTB4 synthesis was 1.02 times higher in group with a BMI of 17.36kg/m2 compared to group with a BMI of 28.41kg/m2, and the fluctuation was significantly reduced from 6.06 to 0.01%. These findings suggest that the concentration of active metabolite in plasma following morniflumate exposure was lower in the obese group compared to the normal group, thus potentially reducing the drug's efficacy.

Differential Responses of Bacterial and Fungal Communities to Siderophore Supplementation in Soil Affected by Tobacco Bacterial Wilt (Ralstonia solanacearum).

Siderophores secreted by microorganisms can promote ecological efficiency and could be used to regulate the unbalanced microbial community structure. The influence of the siderophore activity of Trichoderma yunnanense strain 2-14F2 and Beauveria pseudobassiana strain (2-8F2) on the physiological/biochemical functions and community structure of soil microbes affected by tobacco bacterial wilt (TBW) was studied. DNS Colorimetry and Biolog-eco plates were used to quantify the impacts of strain siderophores on soil enzyme activities and microbial metabolism. Based on Illumina MiSeq high-throughput sequencing, the soil 16S rDNA and ITS sequences were amplified to dissect the response characteristics of alpha/beta diversity and the structure/composition of a soil microbial community toward siderophores. The KEGG database was used to perform the PICRUSt functional prediction of the microbial community. We found that siderophores of 2-14F2 and 2-8F2, at certain concentrations, significantly increased the activities of sucrase (S-SC) and urease (S-UE) in the TBW soil and enhanced the average well color development (AWCD, carbon source utilization capacity) of the microbial community. The metabolic capacity of the diseased soil to amino acids, carbohydrates, polymers, aromatics, and carboxylic acids also increased significantly. The response of the bacterial community to siderophore active metabolites was more significant in alpha diversity, while the beta diversity of the fungal community responded more positively to siderophores. The relative abundance of Actinobacteria, Chloroflexi, and Acidobacteria increased and was accompanied by reductions in Proteobacteria and Firmicutes. LEfSe analysis showed that Pseudonocardiaceae, Gemmatimonas, Castellaniella, Chloridiumand and Acrophialophora altered the most under different concentrations of siderophore active metabolites. The PICRUSt functional prediction results showed that siderophore increased the abundance of the redox-related enzymes of the microbial community in TBW soil. The BugBase phenotypic prediction results showed that the siderophore activity could decrease the abundance of pathogenic bacteria. The study concludes that siderophore activity could decrease the abundance of pathogenic bacteria and regulate the composition of the microbial community in TBW soil. The activities of sucrase (S-SC) and urease (S-UE) in TBW soil were significantly increased. Overall, the siderophore regulation of community structures is a sustainable management strategy for soil ecosystems.

Vitamin D metabolism parameters in hospitalized COVID-19 patients

Background. Recently, clinical benefits among COVID-19 patients, received vitamin D were demonstrated. Features of vitamin D metabolism in the acute period of COVID-19 remain unclear.Objective. To assess the level of 25(OH)D and 1,25(OH)2D in hospitalized COVID-19 patients and cholecalciferol effect on the vitamin D metabolites dynamic.Materials and methods. Group 1 (n = 22) patients received cholecalciferol bolus therapy at a total dose of 100,000 IU. Group 2 patients (n = 22) did not receive cholecalciferol supplementation. Serum 25(OH)D and 1,25(OH)2D levels were estimated for each group on the first and the ninth day of hospitalization.Results. On the ninth day of hospitalization 25(OH)D serum level demonstrated the 45.8 % rise in the Group 1, while in the Group 2 there was a decrease in the 25(OH)D level by 17.9%. At the same time, dynamic evaluation of the 1.25(OH)2D level did not show any differences between the groups, while pairwise comparison on the first and on the ninth days of hospitalization revealed an increase in the active metabolite concentration (p &lt; 0.001) in both groups.Conclusion. Such vitamin D metabolism parameters in the acute period of COVID-19 may be associated with a 1α-hydroxylase activity alteration. Thus, 1.25(OH)2D serum level increase regardless of vitamin D status during the hospitalization could be explained by the COVID-19 course or concomitant corticosteroid medication.

Analysis of the complications of endocrine therapy with tamoxifen in breast cancer: clinical and pharmacogenetic aspects. Prospective pharmacogenetic cohort study

Background. Tamoxifen is the drug of choice in ER-positive breast cancer (BC) therapy for perimenopausal women and one of the endocrine therapy options for menopausal patients. The pharmacological effect of tamoxifen can be influenced by the activity of cytochrome P450 (CYP) enzymes and P-glycoprotein transporters (Pg), and the genes encoding them have broad polymorphism, affecting serum concentrations of active metabolites. This article presents the overall results of a prospective population-based study of the clinical significance of genetic polymorphism of tamoxifen metabolic enzymes and transporters in breast cancer patients after radical treatment receiving adjuvant endocrine therapy with tamoxifen in outpatient settings during 2018-2019. The study was approved by the Research Ethics Committee of the Russian Medical Academy of Continuing Professional Education.&#x0D; Aim. To analyze the clinical presentation of endocrine therapy with tamoxifen in the adjuvant regimen and to assess the association of polymorphisms of genes encoding cytochrome P450 enzymes and drug transporter proteins with adverse events in BC patients.&#x0D; Materials and methods. One hundred and four women with stage I-III luminal breast cancer receiving adjuvant tamoxifen were examined for the presence of CYP2D6, CYP2C, and the following CYP3A gene polymorphisms: CYP2D6*4, CYP3A5*3, CYP2C9*2, CYP2C9*3, CYP2C19*2, CYP2C19*3, as well as the ABCB1 gene polymorphic marker (C3435T) encoding the P-glycoprotein. The allelic variants were identified using the real-time polymerase chain reaction; the test was performed in the Research Center of the Russian Medical Academy of Continuing Professional Education. The study material was buccal epithelium (double sampling) taken after informed consent signing.&#x0D; Results. Association analysis showed the association of different genetic polymorphisms of CYP2D6, CYP3A5, CYP2C9, and ABCB1 with tamoxifen adverse drug reactions, indicating the clinical significance of these polymorphisms.&#x0D; Conclusion. With the implementation of genetic testing of the studied polymorphisms into the routine clinical practice of oncologists prescribing tamoxifen and gynecologists involved in the follow-up of breast cancer patients receiving endocrine therapy in the adjuvant mode, there will be an opportunity for more effective and safer pharmacotherapy.

Comparative effects of human-equivalent low, moderate, and high dose oral prednisone intake on autoimmunity and glucocorticoid-related toxicity in a murine model of environmental-triggered lupus.

Autoimmune diseases can be triggered by environmental toxicants such as crystalline silica dust (cSiO2). Here, we characterized the dose-dependent immunomodulation and toxicity of the glucocorticoid (GC) prednisone in a preclinical model that emulates onset and progression of cSiO2-triggered lupus. Two cohorts of 6-wk-old female NZBWF1 mice were fed either control AIN-93G diet or one of three AIN-93G diets containing prednisone at 5, 15, or 50 mg/kg diet which span human equivalent oral doses (HED) currently considered to be low (PL; 5 mg/d HED), moderate (PM; 14 mg/d HED), or high (PH; 46 mg/d HED), respectively. At 8 wk of age, mice were intranasally instilled with either saline vehicle or 1 mg cSiO2 once weekly for 4 wk. The experimental plan was to 1) terminate one cohort of mice (n=8/group) 14 wk after the last cSiO2 instillation for pathology and autoimmunity assessment and 2) to maintain a second cohort (n=9/group) to monitor glomerulonephritis development and survival. Mean blood concentrations of prednisone's principal active metabolite, prednisolone, in mice fed PL, PM, and PH diets were 27, 105, 151 ng/ml, respectively, which are consistent with levels observed in human blood ≤ 12 h after single bolus treatments with equivalent prednisone doses. Results from the first cohort revealed that consumption of PM, but not PL diet, significantly reduced cSiO2-induced pulmonary ectopic lymphoid structure formation, nuclear-specific AAb production, inflammation/autoimmune gene expression in the lung and kidney, splenomegaly, and glomerulonephritis in the kidney. Relative to GC-associated toxicity, PM diet, but not PL diet, elicited muscle wasting, but these diets did not affect bone density or cause glucosuria. Importantly, neither PM nor PL diet improved latency of cSiO2-accelerated death. PH-fed mice in both cohorts displayed robust GC-associated toxicity including body weight loss, reduced muscle mass, and extensive glucosuria 7 wk after the final cSiO2 instillation requiring their early removal from the study. Taken together, our results demonstrate that while moderate doses of prednisone can reduce important pathological endpoints of cSiO2-induced autoimmunity in lupus-prone mice, such as upstream ectopic lymphoid structure formation, these ameliorative effects come with unwanted GC toxicity, and, crucially, none of these three doses extended survival time.

Abstract 5691: Preclinical evaluation of TFX05-01, a selective AKR1C3- targeted prodrug for solid tumor

Abstract Objective: Aldo-keto reductase 1C3 (AKR1C3), is a member of the aldo-keto reductase superfamily, catalyzing the NADP(H)-dependent stereospecific reduction of various aldehydes and ketones. AKR1C3 is overexpressed in a variety of cancer cells, including hepatocellular carcinoma (HCC), castration-resistant prostate cancer (CRPC), and leukemia cells. This study is to investigate the in vitro and in vivo antitumor activity of TFX05-01, a selective AKR1C3-activated anticancer prodrug, in preclinical models of AKR1C3 overexpressing cells. The studies provide solid foundation for nomination of TFX05-01 for clinical trials. Method: Enzymatic activation of TFX05-01 was investigated in vitro using recombinant human AKR1C3. Cellular anti-proliferative activity was evaluated with a range of AKR1C3 overexpressed or low expressed cell lines. The in vivo antitumor activity was evaluated in various CDX mouse models with high expression of AKR1C3, including HepG2 and castration-resistant prostate VCaP, as well as PDX leukemia models Result: TFX05-01 is a prodrug which selectively releases a DNA alkylating agent (TFX05-01A) upon exposure to AKR1C3. TFX05-01 inhibited cell proliferation in several AKR1C3 overexpressed HCC cell lines with an IC50 ≤ 100 nM. In contrast, TFX05-01 showed much lower anti-proliferative activity in low or no AKR1C3 expressed cells with an IC50 value greater than 1 μM. The cytotoxic potency of TFX05-01 in cancer cells correlates with the level of AKR1C3 expression, and the cytotoxic activity of TFX05-01 was inhibited when used in combination with a specific AKR1C3 inhibitor (IC50: 0.7 nM without inhibitor vs 188 nM with inhibitor in SNU-878 cells). TFX05-01 showed antitumor efficacy in AKR1C3 highly expressed HepG2 subcutaneously implanted xenograft model (TGI = 97% @2 mpk, QW, 3 doses IV). Concomitant PK studies showed that the concentration of active metabolites (TFX05-01A) in tumor was significantly higher (15~50 times) than that in plasma, which correlates with the selective release of the active DNA alkylating agent upon exposure to AKR1C3 in tumor tissues. Conclusion: TFX05-01 is a novel selective AKR1C3-activated prodrug, which is different from traditional non-selective alkylating agents for cancer therapy. Preclinical studies have shown profound in vivo efficacy of TFX05-01 in AKR1C3 overexpressed mouse tumor xenograft models without marked toxicity. TFX05-01 represents a novel treatment option for AKR1C3 expressing solid cancers. Preclinical GLP safety evaluations were promising and TFX05-01 was nominated for clinical trials. Citation Format: Charles Z Ding, Zhe Cai, Wei Sha. Preclinical evaluation of TFX05-01, a selective AKR1C3- targeted prodrug for solid tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5691.

Analysis of free concentrations of lamotrigine and active oxcarbazepine metabolite in clinical patients by hollow-fiber centrifugal ultrafiltration.

Aim: To establish a simple and accurate method to explore the correlation between free and total concentrations of lamotrigine (LTG) and the active oxcarbazepinemetabolite monohydroxy derivative (MHD) (10,11-dihydro-10-hydroxycarbamazepine) in clinical patients. Materials & methods: Serum samples were prepared by hollow-fiber centrifugal ultrafiltration and then injected into UPLC for analysis. Results: Absolute recovery was as high as approximately 90.1-98.6% with excellent precision (relative standard deviation <6.7%). Analysis time was reduced to 5min. There were significant individual differences in the protein binding rates of both LTG and MHD that were probably due to the use of different clinical patients. Conclusion: Free concentrations of LTG and MHD cannot be estimated by total concentration in specific clinical patients. Free drug monitoring of LTG and MHD in clinical therapeutic drug monitoring is important and essential.

Development of a Sensitive and High-Throughput Assay for Simultaneous Quantification of 5 Tyrosine Kinase Inhibitors and 2 Active Metabolites in Human Plasma Using Ultra-high Performance Liquid Chromatography Coupled to Tandem Mass Spectrometry.

Breakpoint cluster region-Abelson (BCR-ABL) tyrosine kinase inhibitors (TKIs) demonstrate improved therapeutic efficacy in chronic myeloid leukemia (CML). However, drug-drug interactions, nonadherence, and host-related factors may influence plasma concentrations. Therefore, therapeutic drug monitoring may be necessary for patients presenting inadequate treatment responses or adverse events. Herein, the authors aimed to develop a more sensitive and high-throughput method than those previously reported to simultaneously quantify 5 TKIs (imatinib, nilotinib, dasatinib, bosutinib, and ponatinib) and 2 active metabolites (N-desmethyl imatinib and N-desmethyl ponatinib) using ultra-performance liquid chromatography coupled with tandem mass spectrometry. Plasma samples were prepared according to a solid-phase extraction protocol using an Oasis MCX µElution plate. The assay fulfilled the requirements of the US Food and Drug Administration for assay validation, with a lower limit of quantification of 0.2 ng/mL for dasatinib, 0.3 ng/mL for N-desmethyl ponatinib, 0.5 ng/mL for N-desmethyl imatinib, bosutinib, and ponatinib, and 2.5 ng/mL for imatinib and nilotinib. Within-batch and batch-to-batch precision at the lower limit of quantification and quality control levels were within 14.3% and 10.9%, respectively. Within-batch and batch-to-batch accuracies ranged from 15.5% to 13.0% and 5.70% to 7.03%, respectively. A positive electrospray ionization mode was used with a run time of 6.0 minutes. The assay applicability was verified by the successful measurement of 78 clinical samples from patients undergoing CML therapy. The method allows assessment of trough concentrations of TKIs and active metabolites in patients with CML, and hence can be used to assess blood samples in routine clinical settings.

Microangiopathy associated with gemcitabine: a drug interaction with nab-paclitaxel? A case series and literature review.

Gemcitabine and nab-paclitaxel association can be used in first- or second-line treatment for metastatic pancreatic adenocarcinoma. Here, we report five cases of supposed gemcitabine-induced thrombotic microangiopathy (G-TMA), four of them with nab-paclitaxel. We assumed that nab-paclitaxel could be responsible for a potential drug interaction with gemcitabine, increasing the risk of thrombotic microangiopathy occurrence. Clinicians reported cases of supposed G-TMA that were declared to the Pharmacovigilance center. We collected the patients' data (clinical and biological characteristics), calculated an incidence rate of G-TMA in our center, and a Naranjo score for each patient. We also reviewed literature on a potential drug interaction between nab-paclitaxel and gemcitabine. Four patients were treated with nab-paclitaxel/gemcitabine and one with gemcitabine alone. The time onset of supposed G-TMA was 2 to 11months. Patients developed anemia, thrombocytopenia, and renal failure. The incidence rate of supposed G-TMA was 2.7% in our center compared to 0.31% (Meyler's Side Effect of Drugs) and 0.01% in the gemcitabine's summary of product characteristics. Literature review outlined an increase of gemcitabine's plasmatic concentrations induced by nab-paclitaxel (Drugs® website) and a potentiation of gemcitabine's effect by nab-paclitaxel in murine models. This study showed that nab-paclitaxel inhibits cytidine deaminase's activity (responsible for gemcitabine's metabolism) and increases gemcitabine's active metabolite concentrations (gemcitabine triphosphate) in tumor tissues. High incidence rate of G-TMA was observed in our cohort due to a potential drug interaction between nab-paclitaxel and gemcitabine with an increased risk of developing G-TMA. Additional pharmacological and pharmaco-epidemiological investigations are mandatory to explore this hypothesis.

Evaluation of efficacy and safety after replacement of methyl hydrogen with deuterium at methyl formate of Clopidogrel

Background and PurposeDespite being a first-line clinical drug, thienopyridines have many unsatisfactory aspects, including the low bioavailability of clopidogrel(CLP) and the high bleeding risk of prasugrel. We synthesized deuterium clopidogrel(D-CL, patented in China) to alleviate the deficiency of CLP in clinical, such as a slow onset, a greater influence of gene polymorphism, and a high frequency of drug-drug interaction. Experimental ApproachMolecular docking was used to analyze the affinity between D-CL and the P2Y12 receptor. The levels of active metabolites of D-CL were detected using HPLC/MS-MS and the activities of main metabolic enzymes were analyzed; Subsequently, platelet aggregation function, thrombus model were used to evaluate the pharmacodynamics of D-CL. Finally, the safety of D-CL were evaluated through examination of blood routine, PT, APTT, bleeding time, serological tests, liver pathological biopsy, liver cell apoptosis and detection of apoptosis-related proteins. Key ResultsThe introduction of deuterium made the binding of CLP to P2Y12 receptor more stable, improved the concentration of active metabolites, and substantially reduced the inhibition of major metabolic enzymes, including CYP2B6, CYP2C9, and CYP2C19, thereby, exerting better antiplatelet effects without increasing the risk of bleeding, along with a concomitant decrease in the apoptosis of hepatocytes.

Abstract 14097: Pharmacometabolomic Profiling Of The General Population: Relation Of Active Metabolite Levels To Cardiovascular Risk Factor Control And Manifest Atherosclerosis

Introduction: The use of medications in the general population has increased over time. Information on active metabolite concentrations for common drugs in the general population is limited. Recent advances in metabolomic technologies have made high-throughput profiling of many active metabolites in large epidemiological cohorts increasingly feasible. Aim: 1. Prospective assessment of the proportion of measurable active metabolite levels of major drugs in the general population using mass spectrometry. 2. Relation of cardiovascular (CV) drugs with inadequate risk factor control and CV disease. Methods: Assessment of CV risk factors by coronary CT angiography and carotid ultrasound imaging in a large prospective cohort of 6,251 individuals randomly selected from the general population in Malmö, Sweden (age 50-64 years). Untargeted metabolomic profiling of fasting plasma was performed by Metabolon, USA in a random subset of 3,986 subjects. Results: Intake of at least one prescribed drug was reported in 1840 subjects (46%). Combination drugs were reported in 249 subjects (6%). The most common drug classes reported were lipid-lowering (n=369, 9% of which most were statins), beta blockers (n=307, 8%), ARB (n=272, 7%), and ACE inhibitors (268, 7%), followed by levothyroxine, CCB, antidepressants, glucocorticoids, PPI, antidiabetic, bronchodilators and diuretics. For major CV drugs, detectable active metabolite levels ranged from 54% (atorvastatin and enalapril) to 96% (metoprolol and metformin). Non-detectable levels of lipid-lowering, antihypertensive, and antidiabetic drugs were associated with higher LDL, cholesterol, BP and glucose, although only antidiabetic drugs were significant (p&lt;0.05). Non-detectable levels of lipid-lowering and antihypertensive drugs were also non-significantly associated with increased coronary calcium and carotid plaque. Conclusion: Our study provides an overview of the distribution of common drugs with detectable levels in a contemporary Swedish population. Pharmacometabolomic profiling revealed that non-measurable levels of common CV drugs were associated with lower risk factor control and non-significant trends towards more atherosclerotic disease by imaging in a substantial number of subjects.

Pharmacokinetic Modeling of Ketamine Enantiomers and Their Metabolites After Administration of Prolonged‐Release Ketamine With Emphasis on 2,6‐Hydroxynorketamines

Modeling of metabolite kinetics after oral administration of ketamine is of special interest because of the higher concentrations of active metabolites because of the hepatic first-pass effect. This holds especially in view of the potential analgesic and antidepressant effects of 2R,6R- and 2S,6S-hydroxynorketamine at low doses of ketamine. Therefore, a 9-compartment model was developed to analyze the pharmacokinetics of ketamine enantiomers and their metabolites after racemic ketamine administered intravenously (5 mg) and as 4 doses (10, 20, 40, and 80 mg) of a prolonged-release formulation (PR-ketamine). Using a population approach, the serum concentration-time data of the enantiomers of ketamine, norketamine, dehydronorketamine, and 2,6-hydroxynorketamine obtained in 15 healthy volunteers could be adequately fitted. The estimated model parameters were used to simulate serum concentration-time profiles; after multiple dosing of PR-ketamine (2 daily doses of 20 mg), the steady-state concentrations of R- and S-ketamine were 1.4 and 1.3 ng/mL, respectively. The steady-state concentration of 2R,6R-hydroxynorketamine exceeded those of R-norketamine (4-fold), R-dehydonorketamine (8-fold), and R-ketamine (46-fold), whereas that of 2S,6S-hydroxynorketamine exceeded that of S-ketamine by 14-fold. The modelmaybeusefulforidentifyingdosingregimens aiming at optimal plasma concentrations of 2,6-hydroxynorketamines.