Occupational survey-based evidence of health status and welfare problems of workers with pneumoconiosis in China

Background

Pneumoconiosis is the most dangerous occupational disease in China. According to unofficial records, nearly million migrant workers were affected by pneumoconiosis in 2011, with the number increasing annually. Among them, a large number of migrant workers suffering from pneumoconiosis were not medically diagnosed. Therefore, fundamental questions remain unanswered: what is the background of workers who receive a diagnosis of pneumoconiosis, and how does pneumoconiosis affect their future and well-being?

Methods

In this study, we identified and surveyed 1,134 workers with pneumoconiosis in seven selected regions in China with substantially high incidences of pneumoconiosis by using a combination of cluster sampling, convenience sampling, and snowball sampling. We used demographic, medical, and rehabilitation conditions and welfare questionnaires to collect the data.

Results

The findings highlighted the socioeconomic status of patients with pneumoconiosis. The majority of workers with pneumoconiosis were adult men who had received no higher education, who lived in rural households, and who were employed in mining or manufacturing industries. Among these workers, 52.8% had been exposed to dust at work for more than 10 years, and 53.1% received a diagnosis of stage II or III pneumoconiosis. More than half of the workers (569 workers, 50.2%) did not receive comprehensive, routine treatment; 33.4% (379 workers) visited a doctor when they experienced physical discomfort, and 6.6% (75 workers) never received treatment. Only 156 workers (13.8%) received rehabilitation services, whereas 978 workers (86.2%) never did. The study results also revealed the severe financial difficulties faced by patients with pneumoconiosis. Only 208 workers (18.3%) had access to work-related injury insurance, with the cost of pneumoconiosis treatment being a substantial burden for 668 workers (60.6%).

Conclusion

In this study, we explored the existing health and welfare problems faced by workers with pneumoconiosis in China and identified the social injustice and health disparities that these workers experience. We also clarified the primary challenges in implementing safety, health, and welfare policies for these workers and those who are exposed to high-risk environments, such as those working in mining.

[ALK-positive large B-cell lymphoma with EBV infection or cyclin D1 expression: a clinicopathological analysis of 3 cases]

Objective: To investigate the clinicopathological features and misdiagnosis factors of ALK positive large B-cell lymphoma (ALK⁺LBCL). Methods: The clinicopathological data of 3 patients with ALK⁺LBCL in the Department of Pathology, the Affiliated Hospital of Xuzhou Medical University from 2010 to 2021 were collected retrospectively. Immunohistochemistry (IHC) was used for immunophenotyping, in-situ hybridization (ISH) for EBV-encoded RNA (EBER) detection, in-situ fluorescence hybridization (FISH, break-apart probes) for ALK, MYC, and CCND1 translocations. Next-generation sequencing (NGS) was used for the detection of gene fusions and mutations. And clinicopathological features and prognosis of patients were analyzed. Results: Among the 3 ALK⁺LBCL patients, there were 2 males and 1 female, aged 42, 59, and 39 years, respectively, none of which presented with B symptoms. Case 1 showed systemic lymphadenopathy with elevated serum EBV DNA loading, while cases 2 and 3 presented with extranodal lesions in the nasal and hard palate, respectively. Bone marrow biopsies were performed in cases 1 and 3, and neither showed involvement. Case 1 was at clinical stage Ⅲ while both cases 2 and 3 were at stage Ⅰ, and IPI score ranged 0-1 in all cases. The morphology of these cases was similar. The architecture was effaced by sheets of cohesive large cells growing in extensive infiltration and intra-sinus growth pattern. The neoplastic cells showed immunoblastic or plasmablastic morphology, and large anaplastic cells were easily found. The tumor cells expressed ALK protein cytoplasmically in almost all cells, with ALK gene translocations detected by FISH. Common B-cell and T-cell markers, including CD20, PAX5, CD19, CD2, CD3, CD5, CD7, CD43, CD56, and bcl-2, were negative, while plasmacytic differentiation markers, including CD138, CD38, and MUM1, were positive; CD22, BOB1 and OCT2 were variably expressed. CD10 was strongly expressed only in case 3. All cases were negative for bcl-6 but positive for CD4, perforin, CD30 (partial cells), pSTAT3 (diffusely), and MYC (40%-50%). The Ki-67 index was ranged 60%-70%. MYC translocation was not detected in any case by FISH. In case 1, EBER was strongly positive in>90% of tumor cells. Case 3 was diffusely positive for cyclin D1 but negative for SOX11 expression and CCND1 translocation. All cases harbored ALK fusion genes detected by NGS. In case 1, the fusion partner was TFG, which had not been reported in DLBCL, while in the other 2 cases, ALK fused with the CTCL gene, which was commonly seen in ALK⁺LBCL. Cases 1 and 3 were treated with ECHOP-based chemotherapy for six cycles and were followed up for 70 and 27 months, respectively, and both achieved complete remission. Conclusions: ALK⁺LBCL cases with diffuse EBER-positivity reported in this study show TGF as a new fusion partner of ALK in DLBCL, together with cyclin D1 expression. These rare cases are easily confused with EBV positive diffuse large B-cell lymphoma, not otherwise specified (EBV⁺DLBCL, NOS), cyclin D1 positive diffuse large B-cell lymphoma (cyclin D1⁺DLBCL) and ALK positive anaplastic large cell lymphoma (ALK⁺ALCL), resulting in misdiagnosis. Being aware of these rare phenotypes is essential for pathologists to diagnose ALK+LBCL and guide appropriate treatment accurately.

Nonprofit capacities and emergency management during the COVID-19 pandemic: Insights from a Taiwan-based international nonprofit organization

During the COVID-19 pandemic, some nonprofit organizations (NPOs) have been struggling to maintain their operations, while others are able to coordinate with partners to provide programs and services locally and globally. This study explores how NPOs are able to survive and actively engage in local and global COVID-19 responses by investigating the organizational capacities of the Tzu Chi Foundation, a Taiwan-based international NPO. This study employs interview data and secondary data from a variety of sources to answer the research questions. Through this case study, we find that Tzu Chi Foundation's capacity to coordinate local and global COVID-19 issues quickly, broadly, and effectively can be attributed to three main factors: (1) clear mission and charismatic leadership, (2) rich experience of disaster relief and recovery strategies, and (3) committed and active volunteers. Moreover, we find that financial management capacity and adaptive capacity are two crucial kinds of capacity for enabling the Tzu Chi Foundation to survive and continuously engage in emergency responses during the pandemic. We conclude with implications for future nonprofit capacity and emergency management research.

Six Cs of pandemic emergency management: A case study of Taiwan's initial response to the COVID-19 pandemic

A review of the disaster literature indicates that emergency responses to pandemics are often understudied; the current COVID-19 crisis provides an important opportunity to improve awareness and understanding about this and other contagious and disruptive diseases. With this in mind, this study examines Taiwan's response to COVID-19 because it was successful in spite of a high probability of contagion. The paper first explores the assertion that cognition, communication, collaboration, and control are vital for effective disaster response; it then indicates the need to consider two additional Cs: confidence (trust of government's competency) and coproduction (public participation in disaster transmission prevention). The paper also conducts a qualitative descriptive study of the Taiwan government's response timeline with examples of each of these concepts in action. To further illustrate the need for the two additional Cs, survey data illustrate how public confidence serves as a pivot between government's COVID-19 response and citizen coproduction in COVID-19 transmission prevention.

No time for composting: Subjective time pressure as a barrier to citizen engagement in curbside composting

Citizen engagement in waste management and recycling programs is crucial in achieving environmental sustainability. Existing studies have explored the determinants of waste management and recycling behavior as well as the adoption of selected waste management and recycling programs at both the individual and organizational levels. However, existing research has not explored, from a civic engagement perspective, why individuals who possess selected waste management and recycling tools fail to use them. Through individual level analysis, this study examines the reasons why residents fail to use their green curbside composting carts. Results indicate that subjective time pressure explains why individuals do not use their composting carts. Additionally, age and household size have different effects on the failure to use green curbside composting carts.

MiRNA-139-3p inhibits the proliferation, invasion, and migration of human glioma cells by targeting MDA-9/syntenin

Gliomas are the most common primary malignant brain tumor in adults. Although these tumors are aggressive and frequently lethal, there are currently few therapeutic approaches available to prolong patient survival. MicroRNAs play important roles in regulating the expression of genes that control diverse cellular processes. Here, we investigated the expression and function of miR-139-3p in gliomas using clinical specimens, cultured cells, and a mouse xenograft tumor model. We found that miR-139-3p expression is markedly lower in human glioma tissues than in normal brain tissues. We identified melanoma differentiation-associated gene-9 (MDA-9)/syntenin, an adaptor protein implicated in tumor metastasis, as a novel direct target of miR-139-3p and showed that syntenin mRNA and miR-139-3p levels were inversely correlated in clinical specimens (r = -0.6817, P = 0.0002). Overexpression of miR-139-3p in human glioma cell lines inhibited cell proliferation, migration, and invasion, and these effects were rescued by co-transfection with syntenin. Our results indicate that miR-139-3p plays a significant role in controlling behaviors associated with the malignant progression of gliomas, and we identify the miR-139-3p-syntenin axis as a potential therapeutic target for glioma.

The EZH2 inhibitor GSK343 suppresses cancer stem-like phenotypes and reverses mesenchymal transition in glioma cells

Enhancer of zeste homolog 2 (EZH2) is the catalytic unit of polycomb repressive complex 2 (PRC2) which epigenetically silences many genes involved in tumor-suppressive mechanisms via the trimethylation of lysine 27 of histone H3 (H3K27me3). We recently found that overexpression of EZH2 was associated with poor outcome of glioblastoma (GBM). In this study, we examined the antitumor effects of the EZH2 inhibitor GSK343 on glioma cells in vitro and in vivo. The proliferation and cell cycle of glioma cells was measured. Wound healing assay and transwell invasion assay were performed to evaluate the capacity of migration and invasion of glioma cells. Western blot, qPCR, immunoprecipitation and fluorescent staining were used to test the levels of EZH2 and associated proteins. Spheroid formation assay and clonogenic assays were conducted to assess the stemness of glioma stem cells. Finally, the effect of GSK343 was measured through a nude mice model with intracranially xenotransplanted glioma. We found that GSK343 reduced proliferation, attenuated cell motility and reversed epithelial-mesenchymal transition in U87 and LN229 glioma cells. GSK343 also suppressed the stemness of cell lines and patient derived glioma stem cells. Further, GSK343 inhibited histone H3K27 methylation and upregulated the expression of EZH2 target genes thereby regulating the levels of markers involved in epithelial-mesenchymal transition and stemness. Taken together, our results indicate that GSK343 could be a potential drug against glioblastoma.

Metabolism of two analgesic agents, tramadol-n-oxide and tramadol, in specific pathogen-free and axenic mice

The in vivo metabolism of both tramadol-N-oxide (TNO) and tramadol was investigated in urine pools obtained from 0-24 h after a single 300 mg kg-1 oral dose administration of each compound to specific pathogen-free and axenic mice. Unchanged TNO (< or =42% of the initial drug sample), tramadol, and 23 metabolites from TNO-treated mice and unchanged tramadol (< or =15% of the sample) plus 20 metabolites from tramadol-treated mice were profiled, quantified and tentatively identified on the basis of atmospheric pressure ionization mass spectrometry (API-MS) and tandem mass spectrometry (MS/MS) data. Of the tramadol metabolites, five (M1-5) have been previously identified in mice. Of the tramadol and TNO metabolites, six (M18-23) are new metabolites. The tramadol and TNO metabolites were formed via the following seven metabolic pathways: N-oxide reduction (TNO), O/N-demethylation, cyclohexyloxidation, oxidative N-dealkylation, dehydration (TNO), N-oxidation (tramadol), and glucuronidation. Pathways 1-3 appear to be predominant steps forming four major O/N-desmethyl and hydroxycyclohexyl metabolites, and in conjunction with pathway 7, formed six minor glucuronides. Both tramadol-N-oxide and tramadol are extensively metabolized in mice, and no significant qualitative or quantitative differences in metabolism were observed between specific pathogen-free and axenic mice with the exception of a greater amount of unchanged TNO in axenic mice than in specific pathogen-free mice, more M2 in specific pathogen-free mice than in axenic mice in the TNO-dosed mice, and visa versa for M2 of tramadol-dosed mice.

Metabolism of the antineoplastic and immunosuppressive drug 2-CdA (Leustatin®) in animals and humans

1. The in vivo metabolism of the antineoplastic and immunosuppressive drug 2-CdA (Leustatin) was investigated in mice, monkeys and humans after a single subcutaneous dose of cladribine 60 mg kg(-1) to eight male and eight female mice and 10 mg kg(-1) to one male and one female monkey, and an intravenous infusion dose of cladribine 22-45 mg(-1) per subject to 12 male patients. 2. Plasma (1 h), red blood cells (1 h) and faecal samples (0-24 h) were obtained from mice and monkeys, and urine samples (0-24 h) were obtained from these species and humans. 3. Unchanged cladribine (urine: 47% of the sample in human; 60% of the sample in mouse; 73% of the sample in monkey) and 10 metabolites, consisting of four phase I metabolites (M1-3, M7) and six phase II metabolites -- five glucuronides (M4, M6, M8-10) and one sulfate (M5) -- were profiled, characterized and tentatively identified in plasma, red blood cells, and faecal and urine samples on the basis of API ionspray-mass spectrometry (MS) and MS/MS data. 4. Metabolites were formed via the following three metabolic pathways: oxidative cleavage at the adenosine and deoxyribose linkage (A); oxidation at adenosine/deoxyribose (B); and conjugation (C). 5. Pathways A and B appear to be major steps, forming four oxidative/cleavage metabolites (M1-3, M7) (each 3-20% of the sample). 6. Pathway C along or in conjunction with pathways A and B produced cladribine glucuronide, cladribine sulfate and four glucuronides of oxidative/cleavage metabolites in minor/trace quantities (each < or = 5% of the sample). 7. In addition, the in vitro metabolism of cladribine was conducted using rat and human liver microsomal fractions in the presence of an beta-nicotinamide adenine dinucleotide phosphate-generating system. Unchanged cladribine (> or = 90% of the sample) plus three minor metabolites, M1-3 (each < 8% of the sample), were profiled and tentatively identified by thin-layer chromatography and MS data. 8. Cladribine is not extensively metabolized in vitro and in vivo in all species. However, humans appear to metabolize cladribine to a greater extent than other animals.

Hepatic metabolism of two alpha-1A-adrenergic receptor antagonists, phthalimide-phenylpiperazine analogs (RWJ-69205 and RWJ-69471), in the rat, dog and human

The In vitro metabolism of two alpha-1A-adrenergic antagonists, RWJ-69205 and RWJ-69471 (phthalimide-phenylpiperazine analogs), was assessed after 30 and 60 min incubations with rat, dog and human hepatic S9 fractions in the presence of an NADPH-generating system. Unchanged RWJ-69205 (> or = 72% of the sample in all species) plus 3 metabolites from the RWJ-69205 incubations, and unchanged RWJ-69471 (> or = 60% of the sample in all species) and 7 metabolites from the RWJ-69471 incubations, were profiled, quantified, and tentatively identified on the basis of API-MS and MS/MS data. The formation of RWJ-69205 and RWJ-69471 metabolites are via the following five metabolic pathways: 1. phenylhydroxylation, 2. O-dealkylation, 3. oxidative N-dealkylation, 4. N-dephenylation, and 5. dehydration. Pathway 1 formed 2 major/moderate hydroxy-phenyl metabolites of 2 analogs (4-17%) in all species, and pathway 2 produced 2 O-desisopropyl metabolites of 2 analogs in major/moderate (7-16%) in rat and human, and in trace (< 1%) in dog; in conjunction with pathway 1, yielded a minor diphenolic metabolite (< 1-2%) in RWJ-69471. Pathway 3 formed a minor N-dealkylated metabolite, isopropoxyphenyl piperazine (< 1-6%) in all species of 2 analogs. Pathways 4 and 5 produced 2 minor N-desphenyl metabolite and dehydrated metabolite, respectively, in rat and human S9 (< or = 1-2%) in RWJ-69471. Both RWJ-69205 and RWJ-69471 were less extensively metabolized in the dog. However, rat and human appeared to metabolize RWJ-69471 more extensively than RWJ-69205 in this hepatic system.

The Novel, Orally Active, Delta Opioid RWJ-394674 Is Biotransformed to the Potent Mu Opioid RWJ-413216

Although the mu opioid receptor is the primary target of marketed opioid analgesics, several studies suggest the advantageous effect of combinations of mu and delta opioids. The novel compound RWJ-394674 [N,N-diethyl-4-[(8-phenethyl-8-azabicyclo]3.2.1]oct-3-ylidene)-phenylmethyl]-benzamide]; bound with high affinity to the delta opioid receptor (0.2 nM) and with weaker affinity to the mu opioid receptor (72 nM). 5'-O-(3-[(35)S]-thio)triphosphate binding assay demonstrated its delta agonist function. Surprisingly given this pharmacologic profile, RWJ-394674 exhibited potent oral antinociception (ED(50) = 10.5 micromol/kg or 5 mg/kg) in the mouse hot-plate (48 degrees C) test and produced a moderate Straub tail. Antagonist studies in the more stringent 55 degrees C hot-plate test demonstrated the antinociception produced by RWJ-394674 to be sensitive to the nonselective opioid antagonist naloxone as well as to the delta- and mu-selective antagonists, naltrindole and beta-funaltrexamine, respectively. In vitro studies demonstrated that RWJ-394674 was metabolized by hepatic microsomes to its N-desethyl analog, RWJ-413216 [N-ethyl-4-[(8-phenethyl-8-azabicyclo[3.2.1]oct-3-ylidene)-phenylmethyl]-benzamide], which, in contrast to RWJ-394674, had a high affinity for the mu rather than the delta opioid receptor and was an agonist at both. Pharmacokinetic studies in the rat revealed that oral administration of RWJ-394674 rapidly gave rise to detectable plasma levels of RWJ-413216, which reached levels equivalent to those of RWJ-394674 by 1 h. RWJ-413216 itself demonstrated a potent oral antinociceptive effect. Thus, RWJ-394674 is a delta opioid receptor agonist that appears to augment its antinociceptive effect through biotransformation to a novel mu opioid receptor-selective agonist.

Metabolism and excretion of the antiepileptic/antimigraine drug, topiramate in animals and humans

The metabolism and excretion of 2,3:4,5-bis-O-(1-methylethylidene)-beta-D-fructopyranose sulfamate (TOPAMAX, topiramate, TPM) have been investigated in animals and humans. Radiolabeled [14C] TPM was orally administered to mice, rats, rabbits, dogs and humans. Plasma, urine and fecal samples were collected and analyzed. TPM and a total of 12 metabolites were isolated and identified in these samples. Metabolites were formed by hydroxylation at the 7- or 8-methyl of an isopropylidene of TPM followed by rearrangement, hydroxylation at the 10-methyl of the other isopropylidene, hydrolysis at the 2,3-O-isopropylidene, hydrolysis at the 4,5-O-isopropylidene, cleavage at the sulfamate group, glucuronide conjugation and sulfate conjugation. A large percentage of unchanged TPM was recovered in animal and human urine. The most dominant metabolite of TPM in mice, male rats, rabbits and dogs appeared to be formed by the hydrolysis of the 2,3-O-isopropylidene group.

Metabolism of the alpha-1A-adrenergic receptor antagonist, pyridine-phenylpiperazine analog (RWJ-69597), in rat, dog and human hepatic S9 fractions -API-MS/MS identification of metabolites

The In vitro metabolism of the alpha-1A-adrenergic antagonist, RWJ-69597, an analog of pyridine-phenylpiperazines, was conducted after incubation with rat, dog and human hepatic S9 fractions in the presence of an NADPH-generating system. Unchanged RWJ-69597 (> or =43% of the sample in all species) plus 9 metabolites were profiled, quantified, and tentatively identified on the basis of API-MS and MS/MS data. The four metabolic pathways for the formation of RWJ-69597 metabolites are: 1. methyl/phenyl/piperazinylhydroxylation, 2. N/Odealkylation, 3. N-dephenylation, and 4. dehydration. Pathway 1 formed 1 major (8-36%) and 3 minor (<1-3%) hydroxylated metabolites. Pathway 2 produced 2 moderate/minor N/O-dealkylated metabolites (<1- < or =11%), and in conjunction with pathway 1, formed 1 minor diol metabolites (< or =2%). Pathways 3 and 4 generated 2 minor metabolites, N-desphenyl RWJ-69597 (< or =4%) and dehydrated RWJ-69597 (< or =2%), respectively. RWJ-69597 is more extensively metabolized in the rat than the dog or the human in this hepatic system.

Metabolism of the new α-1A-adrenergic receptor antagonist, phthalimide-phenylpiperazine analog (RWJ-69442), in rat, dog and human hepatic S9 fractions, and in rats

The in vitro and in vivo metabolism of RWJ-69442, an alpha-1A-adrenergic receptor antagonist, was investigated after incubation with rat, dog, and human hepatic S9 fractions in the presence of NADPH-generating system, and a single oral/iv dose administration to rats (oral: 100 mg/kg; iv: 10 mg/kg). Unchanged RWJ-69442 (> or =30% of the sample in vitro; < or =47% of the sample in vivo) plus 14 metabolites were profiled, quantified and tentatively identified on the basis of API-MS and MS/MS data. The metabolic pathways for RWJ-69442 are proposed via the 4 steps: 1. phenyl/piperazinylhydroxylation, 2. N/O-dealkylation, 3. N-dephenylation, and 4. dehydration. Pathway 1 formed OH-phenyl-RWJ-69442 (M1, 4-32% in vitro & in vivo), and diOH-RWJ-69442 (M4, <1-4% in vitro & in vivo). Pathway 2 generated O-desisopropyl-RWJ-69442 (M2, <1-21% in vitro & in vivo), N-desmethyl-RWJ-69442 (M3, 2-3% in vitro & in vivo), N-desmethyl-M2 (M6, 1-8% in vitro & in vivo), and N-dealkylated RWJ-69442 (M9, < or =1-17% in vitro & in vivo), and in conjunction with pathway 1 produced 6 minor to major oxidized metabolites, OH-M2 (M5, 1-2% in vitro), OH-M3 (M11, 4-6% in vivo), OH-M9 (M10, <1-34% in vitro & in vivo), O-desisopropyl-M9 (M12, 3-21% in vivo), O-desisopropyl-M10 (M13,2-12% in vivo), and dehydro-M13 (M14, 25% in vivo). Pathways 3 and 4 formed 2 minor metabolites, N-desphenyl-RWJ-69442 (M7, <1-12% in vitro & in vivo) and dehydrated-RWJ-69442 (M8, <1-2% in vitro), respectively. RWJ-69442 is extensively metabolized in vitro in the rat and human (except dog), and in vivo in the rat.

Human hepatic metabolism of the anxiolytic agent, RWJ-51521--API-MS/MS identification of metabolites

The In vitro metabolism of the anxiolytic agent, RWJ-51521 was conducted after incubation with human hepatic S9 fraction in the presence of an NADPH-generating system. Unchanged RWJ-51521 (30% of the sample) and a total of 11 metabolites were profiled, quantified, and tentatively identified on the basis of API (ionspray)-MS/MS data. The 4 proposed metabolic pathways for RWJ-51521 are: (1) N/O-dealkylation, (2) phenylhydroxylation, (3) pyrido-oxidation, and (4) dehydration. Pathway 1 formed 2 major and 3 minor N/O-desalkyl metabolites (M1 & M3, 50%) and in conjunction with pathway 4, formed 2 moderate dehydrated metabolites (M4 & M5, 14%). Pathways 2 and 3 alone, and in conjunction with pathway 4, produced 4 minor metabolites (each < or =2%). RWJ-51521 is extensively metabolized in human hepatic S9 fraction.

Metabolism of the new nonbenzodiazepine anxiolytic agent, RWJ-51204, in mouse, rat, dog, monkey and human hepatic S9 fractions, and in rats, dogs and humans

The in vitro and in vivo metabolism of the nonbenzodiazepine anxiolytic agent, RWJ-51204 was investigated after incubation with mice, rat, dog, monkey, and human hepatic S9 fractions in the presence of NADPH-generating system, and a single oral dose administration to rats (100 mg/kg), dogs (5 mg/kg), and humans (2.5 mg/subject). Plasma and red blood cells (2 h, rat) and urine samples (0-24 h, rat, dog and human) were obtained postdose. Unchanged RWJ-51204 (39-93% of the sample in vitro; < or =5% of the sample in vivo) plus 14 metabolites were profiled, quantified and tentatively identified on the basis of API-MS and MS/MS data, and by comparison of synthetic samples. The in vitro and in vivo metabolic pathways for RWJ-51204 are proposed, and the metabolite formations are via the following five pathways: 1. phenyl oxidation, 2. pyrido-oxidation, 3. N-deethoxymethylation, 4. dehydration, and 5. glucuronidation. Pathway 1 formed 4-hydroxy-2-fluoro-phenyl-RWJ-51204 (M1, 7-24% in vitro; 5-60% in vivo) in major amounts, OH-benzimidazole-RWJ-51204 (M2, 5-8% in vitro and in vivo) and diOH-phenyl-RWJ-51204 (< or =5-16% in vitro and in vivo); in conjunction with pathway 5 produced M1 glucuronide (60% in rat & dog; 17% in human), M2 glucuronide (16% in human). Pathways 2-4 formed minor/trace oxidized, and dehydrated metabolites. RWJ-51204 is extensively metabolized in vitro (except dog) and in vivo in rats, dogs and humans.

Hepatic metabolism of the new antipsychotic agent, mazapertine, in rat--API-MS/MS identification of metabolites

The In vitro biotransformation of the antipsychotic agent, mazapertine was studied after incubation with rat hepatic S9 fraction in the presence of an NADPH-generating system. Unchanged mazapertine (42% of the sample) plus 12 metabolites were profiled, quantified, and tentatively identified on the basis of API (ionspray)-MS/MS data. The proposed metabolic pathways for mazapertine are proposed, and the 6 metabolic pathways are: (1) phenylhydroxylation, (2) piperidyl oxidation, (3) O-dealkylation, (4) N-dephenylation, (5) oxidative N-debenzylation, and (6) dehydration. Pathways 1 to 3 formed 4-OH-phenyl (M1, 10%) and 4-OH-piperidyl (M2, 9%)-mazapertine, O-desisopropyl mazapertine (M3, 17%), and N-desbenzoylpiperidine-mazapertine (M8, 14%) as 4 major metabolites. Mazapertine is extensively metabolized in rat hepatic S9 fraction.

In vitro biotransformation of the analgesic agent, RWJ-51784, in rat, dog and human

RWJ-51784, an analogue of phenyl isoindoles, is a new analgesic agent. The in vitro metabolism of RWJ-51784 was conducted using rat, dog and human hepatic S9 in the presence of an NADPH generating system, and API-ionspray-MS and MS/MS techniques for the metabolite profiling and identification. Unchanged RWJ-51784 (82, 80 & 86% of the sample in rat, dog & human, respectively) plus 6 metabolites were profiled and tentatively identified on the basis of MS data. RWJ-51784 metabolites were formed via the following 3 metabolic pathways: 1. N-demethylation, 2. phenylhydroxylation, and 3. isoindole-oxidation. Pathway 1 produced a moderate or minor metabolite, N-desmethyl-RWJ-51784 (M1; 6% in rat; 5% in dog, 2% in human). Pathway 2 formed 4-hydroxyphenyl-RWJ-51784 (M2; 3-6% in all species). Step 3 formed 2 isoindole-oxidized metaboliotes, OH-indole (M3; 7-8% in all species) and oxo-indole (M4; <1% in all species)-RWJ-51784, and in conjunction with pathway 2 produced 2 trace metabolites, OH-phenyl-OH-isoindole (M5) and OH-phenyl-oxo-isoindole (M6) metabolites. RWJ-51784 is not extensively metabolized in rat, dog and human hepatic S9 fractions.

In vitro metabolism of the analgesic agent, RWJ-37874, in rat and human

RWJ-37874, an analogue of aroyl(aminoacyl)pyrrole, is a new analgesic agent. The in vitro metabolism of RWJ-37874 was conducted using rat and human hepatic S9 in the presence of an NADPH generating system, and API-ionspray-MS and MS/MS techniques for metabolite profiling and identification. Unchanged RWJ-37874 (66 & 86% of the sample in rat & human, respectively) plus four metabolites were profiled and tentatively identified on the basis of MS data. RWJ-37874 metabolites were formed via the following two metabolic pathways: 1. oxidative N-deethylation, and 2. pyrrole-oxidation. Pathway 1 produced a mayor and a minor metabolites, N-desethyl-RWJ-37874 (M1; 34% in rat; 13% in human) and N,N-didesethyl-RWJ-37874 (M3; <0.5% in both species), respectively. Pathway 2 formed hydroxypyrrole-RWJ-37874 (M2; <0.5% in all species), and in conjunction with step 1, formed hydroxy-M1 (M4; <0.5% in rat). RWJ-37874 is substantially metabolized in rat and human hepatic S9 fractions. However, rat appears to metabolize RWJ-37874 more extensively than human via N-dealkylation forming N-desethyl-RWJ-37874 as a major metabolite.

In vitro identification of metabolic pathways and cytochrome P450 enzymes involved in the metabolism of etoperidone

1. In vitro studies have been carried out to investigate the metabolic pathways and identify the hepatic cytochrome P450 (CYP) enzymes involved in etoperidone (Et) metabolism. 2. Ten in vitro metabolites were profiled, quantified and tentatively identified after incubation with human hepatic S9 fractions. Et was metabolized via three metabolic pathways: (A) alkyl hydroxylation to form OH-ethyl-Et (M1); (B) phenyl hydroxylation to form OH-phenyl-Et (M2); and (C) N-dealkylation to form 1-m-chlorophenylpiperazine (mCPP, M8) and triazole propyl aldehyde (M6). Six additional metabolites were formed by further metabolism of M1, M2, M6 and M8. 3. Kinetic studies revealed that all metabolic pathways were monophasic, and the pathway leading to the formation of OH-ethyl-Et was the most efficient at eliminating the drug. On incubation with microsomes expressing individual recombinant CYPs, formation rates of M1-3 and M8 were 10-100-fold greater for CYP3A4 than that for other CYP forms. The formation of these metabolites was markedly inhibited by the CYP3A4-specific inhibitor ketoconazole, whereas other CYP-specific inhibitors did not show significant effects. In addition, the production of M1-3 and M8 was strongly correlated with CYP3A4-mediated testosterone 6beta-hydroxylase activities in 13 different human liver microsome samples. 4. Dealkylation of the major metabolite M1 to form mCPP (M8) was also investigated using microsomes containing recombinant CYP enzymes. The rate of conversion of M1 to mCPP by CYP3A4 was 503.0 +/- 3.1 pmole nmole(-1) min(-1). Metabolism of M1 to M8 by other CYP enzymes was insignificant. In addition, this metabolism in human liver microsomes was extensively inhibited by the CYP3A4 inhibitor ketoconazole, but not by other CYP-specific inhibitors. In addition, conversion of M1 to M8 was highly correlated with CYP3A4-mediated testosterone 6beta-hydroxylase activity. 5. The results strongly suggest that CYP3A4 is the predominant enzyme-metabolizing Et in humans.

In vitro metabolism of the analgesic agent, tramadol-N-oxide, in mouse, rat, and human

Tramadol-N-oxide (TNO, RWJ-38705) is a new analgesic agent, which is believed to produce its analgesic effect following metabolic conversion to tramadol. In the present study, API ionspray-MS and MS/MS techniques were used to profile the in vitro metabolism of TNO in mouse, rat, and human hepatic S9 fractions in the presence of an NADPH generating system. Unchanged TNO represented 60, 24, and 26% of the sample in mouse, rat, and human, respectively. Tramadol, and seven other metabolites were profiled and tentatively identified on the basis of MS analysis and by comparison to synthetic reference samples. TNO metabolites were formed via four Phase I reactions: (1) N-oxide reduction, (2) O-demethylation, (3) N-demethylation, and (4) cyclohexylhydroxylation. TNO was found to be substantially metabolized in hepatic S9 from all three species. The metabolism of TNO to tramadol via N-oxide reduction was greater in rat and human than in mouse.

Evaluation of the excretion and metabolism of the new analgesic agent RWJ-22757 in male and female CR Wistar rats

The excretion and metabolism of (+/-)-trans-3-(2-bromophenyl)octahydroindolizine hydrochloride (RWJ-22757) have been investigated in male and female CR Wistar rats. Radiolabeled [14C] RWJ-22757 was administered orally to each of the rats as a single 60 mg/kg suspension dose. Plasma (0-48 h), urine (0-168 h) and fecal (0-168 h) samples were collected and analyzed. There were no significant gender differences observed in the data. The estimated elimination half-life of the total radioactivity from plasma was 19 h while the estimated elimination half-life of RWJ-22757 was 15 h. Recoveries of total radioactivity in urine and feces were 58.4+/-5.8 and 42.4+/-6.3%, respectively. RWJ-22757 and a total of 11 metabolites were isolated in rat plasma, urine, and fecal extracts. The structures of four of these metabolites were tentatively identified. Unchanged RWJ-22757 accounted for < 4% of the dose in plasma and urine and 28% in feces; thus, indicating the drug was extensively metabolized and either not absorbed well or biliary excreted. Identified metabolites accounted for > 80% of the total radioactivity contained in the samples. The following pathways were used to describe the formation of the metabolites identified in rats: octahydroindolizine ring oxidation, phenyl hydroxylation, octahydroindolizine ring oxidation followed by ring opening to a carboxylic acid function and octahydroindolizine ring oxidation followed by ring opening and N-methylation.

Metabolism of the analgesic drug ULTRAM (tramadol hydrochloride) in humans: API-MS and MS/MS characterization of metabolites

1. Metabolism of the analgesic agent tramadol hydrochloride has been investigated after a single oral administration of tramadol to three male volunteers (100 mg/subject), and a urine pool (4-12h) was obtained. 2. Unchanged tramadol and a total of 23 metabolites, consisting of 11 Phase I metabolites (M1-11) and 12 conjugates (seven glucuronides, five sulphates), were profiled, characterized and tentatively identified in urine on the basis of API ionspray-MS and MS/MS data. 3. Of the metabolites, five (M1-5) had been previously identified. 4. The metabolites were formed via the following six metabolic pathways: (1) O-demethylation, (2) N-demethylation, (3) cyclohexyl oxidation, (4) oxidative N-dealkylation, (5) dehydration and (6) conjugation. 5. Pathways 1-3 appear to be major routes, forming seven O-desmethyl/N-desmethyl and hydroxycyclohexyl metabolites. 6. Pathways 1-3 in conjunction with pathway 6 produced seven glucuronides along with five sulphates. 7. In addition, the in vitro metabolism of tramadol was conducted using a human liver microsomal fraction in the presence of an NADPH-generating system. Unchanged tramadol (82% of the sample) plus eight metabolites (M1, M2, M4-6, tramadol-N-oxide (M31), OH-cyclohexyl-M1 (M32) and dehydrated tramadol-N-oxide), were profiled and tentatively identified on the basis of MS and MS/MS data.

Evaluation of the absorption, excretion and metabolism of [14C] etoperidone in man

1. The absorption, excretion and metabolism of 2-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]-4,5-diethyl-2,4-dihydro-3H-1,2,4- triazole-3-one hydrochloride (etoperidone HCl) was investigated in six healthy men. Subjects were tasted overnight before receiving a single oral dose of a 100 mg solution [14C] etoperidone HCl. 2. Plasma (0-48 h), urine (0-120 h) and faecal (0-120 h) samples were collected. The terminal half-life of the total radioactivity from plasma was 21.7 +/- 2.8h with an apparent clearance of 1.01 +/- 0.08 ml min(-1). Recoveries of total radioactivity in urine and faeces were 78.8 +/- 3.6% and 9.6 +/- 4.1% of the dose, respectively. 3. Etoperidone and 21 metabolites were isolated and identified in the plasma, urine and faecal extracts. Unchanged etoperidone accounted for <0.01% of the dose in all excreta samples. Nine metabolites were identified in the plasma extracts and 21 urinary metabolites were identified. Seven faecal metabolites were identified. 4. Five proposed pathways were used to describe the formation of the metabolites: alkyl oxidation, piperazinyl oxidation, N-dealkylation, phenyl hydroxylation and conjugation. Alkyl oxidation of etoperidone resulted in the formation of 2-[3-[4-(3-chlorophenyl)-1-piperazinyl]propyl]-4-ethyl-2,4-dihydro-5- (1-hydroxyethyl)-3H-1,2,4-triazole-3-one. Piperazinyl oxidation of this metabolite leads to the formation of its N-oxide. N-dealkylation of the piperazinyl group led to the formation of 1-(3-chlorophenyl) piperazine and triazole propionic acid. Phenyl hydroxylation led to three important metabolites in the urine and faeces.

Evaluation of the excretion, and metabolism of the cardiotonic agent bemoradan in male rats and female beagle dogs

The excretion and metabolism of (+/-) [6-(3,4-dihydro-3-oxo-1,4[2H]-benzoxazine-yl)-2,3,4,5-tetrahydro-5-methylpyridazin-3-one] (bemoradan; RWJ-22867) have been investigated in male Long-Evans rats and female beagle dogs. Radiolabeled [14C] bemoradan was administered to rats as a singkle 1 mg/kg suspension dose while the dogs received 0.1 mg/kg suspension dose. Plasma (0-24 h; rat and dog), urine (0-72 h; rat and dog) and fecal (0-72 h; rat and dog) samples were collected and analyzed. The terminal half-life of the total radioactivity for rats from plasma was estimate to be 4.3 +/- 0.1 h while for dogs it was 7.5 +/- 1.3 h. Recoveries of total radioactivity in urine and feces for rats were 49.1 +/- 2.4% and 51.1 +/- 4.9% of th dose, respectively. Recoveries of total radioactivity in urine and feces for dogs were 56.2 +/- 12.0% and 42.7 V 9.9% of the dose, respectively. Bemoradan and a total of nine metabolites were isolated and tentatively identified in rat and dog plasma, urine, and fecal extracts. Unchanged bemoradan accounted for approimately < 2% of the dose in rat urine and 20% in rat feces. Unchanged bemoradan accounted for approximately 5% of the dose in urine and 16% in feces in dog. Six proposed pathways were used to describe the metabolites found in rats and dogs: pyridazinyl oxidations, methyl hydroxylation, hydration, N-oxidation, dehydration and phase II conjugations.

Evaluation of the absorption, excretion, and metabolism of the antihypertensive agent RWJ-26899 in male and female CR Wistar rats and Beagle dogs

The absorption, excretion and metabolism of N-(2, 6-dichlorophenyl)-beta-[[(1-methylcyclohexyl)methoxylmethyl]-N-(phenylmethyl)-1-pyrrolidineethanamine (RWJ-26899; McN-6497) has been investigated in male and female CR Wistar rats and beagle dogs. Radiolabeled [14C] RWJ-26899 was administered to rats as a single 24 mg/kg suspension dose while the dogs received 15 mg/kg capsules. Plasma (0-36 h; rat and 0-48 h; dog), urine (0-192 h; rat and dog) and fecal (0-192 h; rat and dog) samples were collected and analyzed. There were no significant gender differences observed in the data. The terminal half-life of the total radioactivity for rats from plasma was estimated to be 7.7 +/- 0.6 h while for dogs it was 22.9 +/- 4.4 h. Recoveries of total radioactivity in urine and feces for rats were 8.7 +/- 2.9% and 88.3 +/- 10.4% of the dose, respectively. Recoveries of total radioactivity in urine and feces for dogs were 4.1 +/- 1.4% and 90.0 +/- 4.7% of the dose, respectively. RWJ-26899 and a total of nine metabolites were isolated and tentatively identified in rat urine, and fecal extracts. Unchanged RWJ-26899 accounted for approximately 1% of the dose in rat urine and 8% in rat feces. RWJ-26899 and a total of four metabolites were isolated and identified in dog urine, and fecal extracts. Unchanged RWJ-26899 accounted for approximately 1% of the dose in urine and 63% in feces in dog. Five proposed pathways were used to describe the metabolites found in rats: N-oxidation, oxidative N-debenzylation, pyrrolidinyl ring hydroxylation, phenyl hydroxylation and methyl or cyclohexyl hydroxylation. Two biotransformation pathways in dogs are proposed: N-oxidation and methyl or cyclohexyl ring hydroxylation.

Metabolism of the analgesic drug, tramadol hydrochloride, in rat and dog

1. Metabolism of the analgesic agent, tramadol hydrochloride, was investigated after a single oral administration of 14C-tramadol to four rats (50)mgkg(-1) and two dogs (20)mg kg(-1). 2. Recovery of total radioactivity in rat and dog urine samples over 24 h was 73 and 65% of the radioactive dose, respectively. 3. Unchanged tramadol and a total of 24 metabolites, consisting of 16 Phase I metabolites and eight conjugates (seven glucuromides, one sulphate), were isolated and tentatively identified, which accounted for > 52% of the dose in urine of both species. 4. Of the metabolites, five (M1-5) were previously identified. 5. The metabolites were formed via the following six metabolic pathways: O-demethylation, N-demethylation, cyclohexyl oxidation, oxidative N-dealkylation, dehydration and conjugation. 6. Pathways 1-3 appear to be major steps, forming seven O-desmethyl/N-desmethyl and hydroxy-cyclohexyl metabolites in major quantities. 7. Pathways 1-3 in conjunction with pathway 6 produced four glucuronides along with four minor conjugates. 8. In addition, the in vitro metabolism of tramadol was conducted using rat hepatic S9 fraction in the presence of an NADPH-generating system. Unchanged tramadol (30% of the sample) plus nine metabolites, M1-7, tramadol-N-oxide (M31) and OH-cyclohexyl-M1 (M32), were profiled and tentatively identified based on MS and MS/MS data.

In vitro biotransformation of the new antipsychotic agent, RWJ-46344 in rat hepatic S9 fraction: API-MS/MS/MS identification of metabolites

The in vitro biotransformation of the antipsychotic agent, RWJ-46344 was studied after incubation with rat hepatic S9 fraction in the presence of an NADPH-generating system. Unchanged RWJ-46344 (approximately 37% of the sample) plus 12 metabolites were profiled, quantified, and tentatively identified on the basis of API (ionspray)-MS/MS/MS data. The proposed metabolic pathways for RWJ-46344 are proposed, and the six metabolic pathways are 1, O-dealkylation; 2, piperidinyl oxidation; 3, N-debenzylation; 4, phenyl hydroxylation; 5, dehydration; and 6, reduction. Pathways 1 to 3 formed O-desisopropyl RWJ-46344 (M3, approximately 13% of the sample) and its hydroxy-metabolite (M5, approximately 8%), hydroxypiperidinyl RWJ-46344 (M1, approximately 5%) and a phenylpiperidinyl metabolite (M8, approximately 24%) as major and moderate metabolites. Eight minor metabolites (each < 2%) were formed via a combination of six steps. RWJ-46344 is metabolized substantially by this rat hepatic system.

Recent advances in biotransformation of CNS and cardiovascular agents

Compound biotransformation is a very important research area for drug discovery and development. In this review, publications from the metabolism studies of ten compounds, seven CNS and three cardiovascular agents, from the Johnson & Johnson Corp. were reviewed. The seven CNS compounds are: three antipsychotic agents, mazapertine (arypiperazine analog), RWJ-46344 (arypiperidine analog) and risperidone (aryisoxazole-piperidine analog), one antidepressant, etoperidone (arypiperazine analog), one anxiolytic agent, fenobam (aryimidazole urea analog), one muscle relaxant, xilobam (pyrrolidinylidene urea analog), and one antiepileptic agent, topiramate (fructopyranose sulfamate analog). The three cardiovascular agents are: two arylalkylamine calcium channel blockers, bepridil and RWJ-26240, and one thioindolaminidine antianginal agent, RWJ-34130. Other antipsychotic and antidepressant agents with similar analogs (ziprasidone, trazodone and nefazodone) as well as other similar analogs of calcium channel blockers (verapamil) are discussed. In this article, excretion and metabolism (in vitro, in vivo) of compounds are reviewed from the CNS agents to the cardiovascular agents, including structures of parent compounds, their metabolites, metabolic pathways, and methods for the isolation, profiling, quantification and structural identification of unchanged compounds and metabolites. Pharmacological activities of parent compounds and their metabolites are also briefly discussed.

In vitro metabolism of mifepristone (RU-486) in rat, monkey and human hepatic S9 fractions: identification of three new mifepristone metabolites

1. In vitro metabolism of the antiprogestin drug mifepristone (RU-486) was studied after incubation with rat, monkey and human hepatic S9 fractions in the presence of an NADPH-generating system. 2. Unchanged mifepristone (approximately 45% of the sample(s) in rat; approximately 70% in monkey; approximately 65% in human) plus six metabolites, three known and three new, were profiled, quantified and tentatively identified on the basis of MS and MS/MS data. 3. The proposed metabolic pathways for mifepristone are proposed, and the two metabolic steps are (A) N-demethylation and (B) methyl oxidation. 4. Step A formed N-desmethyl mifepristone (M1) in major amounts (approximately 35% s in rat, 16% in monkey and human) and N,N-didesmethyl mifepristone (M2) in minor amounts (< 5% s in all species). Step B, or in conjunction with step A, produced four minor/trace metabolites, namely hydroxymethyl mifepristone (M3), hydroxymethyl M1 (M4), hydroxymethyl M2 (M5) and formyl mifepristone (M6).

Longiberine and O-methyllongiberine, dimeric protoberberine-benzyl tetrahydroisoquinoline alkaloids from Thalictrum longistylum(1)

Two benzyltetrahydroisoquinoline-protoberberine dimers, longiberine (1) and O-methyllongiberine (2), were isolated from the roots of Thalictrum longistylum and represent a new class of dimeric alkaloids. The structure of longiberine (1) was established by spectral and chemical methods. Reductive cleavage of O-ethyllongiberine (4) with Na/liquid NH(3) yielded (+)-(S)-N-methylcoclaurine (5), which determined one-half of the dimer, and 1D and 2D NMR studies arranged the substituents on the protoberberine nucleus. Chemical conversion of thalidezine (6) to 1 via the O-acetyl N,N-didemethyl derivative 9, which was methylenated in the Mannich reaction and N-methylated by the Eschweiler-Clarke procedure, established the second asymmetric center as S and confirmed the ring size and the order of the substituents for 1. Methylation of 1 with diazomethane formed the O-methyl derivative 2, identical with the natural product.

In vitro metabolic products of RWJ-34130, an antiarrythmic agent, in rat liver preparations

The in vitro metabolism of RWJ-34130, an antiarrhythmic agent, was conducted using rat hepatic 9000 x g supernatant (S9) and microsomes in an NADPH-generating system, and the rat liver perfusion. The 100 and 20 microg ml(-1) concentrations of RWJ-34130 aqueous solution were used for microsomal incubation and liver perfusion, respectively. Unchanged RWJ-34130 (approximately 77-78% of the sample in both S9 and microsomes) plus a major metabolite, RWJ-34130 sulfoxide (20% of the sample in both S9 and microsomes) were profiled, isolated and identified from both hepatic S9 and microsomal incubates (60 min) using HPLC and mass spectrometry (MS), and by comparison to a synthetic RWJ-34130 sulfoxide, which was synthesized by reacting RWJ-34130 with MCPBA (meta-chloroperoxy benzoic acid). No unchanged RWJ-34130 was detected in the 3 h liver perfusate, however, 1-phenyl-2-oxo-pyrrolidine was profiled, isolated and identified as a major hydrolyzed metabolite of liver perfusate. RWJ-34130 is not extensively metabolized in vitro in rat hepatic S9 and microsomes. All HPLC metabolic profiles of hepatic S9 and microsomal samples (30 min, 60 min) were qualitatively and nearly quantitatively identical.

Biotransformation of the antipsychotic agent, mazapertine, in dog--mass spectral characterization and identification of metabolites

1. Biotransformation of the antipsychotic agent, mazapertine, was studied after a single oral administration of 14C-mazapertine succinate (10 mg/kg, free base) to six beagle dogs (three male, three female). 2. Following oral administration of 14C-mazapertine, plasma (0-48 h), urine (0-7 days), and faeces (0-7 days) were collected. Recoveries of total radioactivity in urine and faeces were 26.9 and 62.0% of the dose, respectively. 3. Unchanged mazapertine plus 14 metabolites were isolated and identified, which accounted for > 60% of the sample radioactivity in the plasma, 17% of the dose in urine and 28% of the dose in faecal extract. 4. Unchanged mazapertine accounted for < 4% of the radioactive dose in excreta samples and < 21% of the sample radioactivity present in plasma samples. 5. Seven metabolic pathways for the formation of metabolites were identified including: (1) phenyl hydroxylation, (2) piperidyl oxidation, (3) O-dealkylation, (4) N-dephenylation, (5) oxidative N-debenzylation, (6) depiperidylation and (7) conjugation. 6. Pathways 1, 2, 5 and 6 produced 4-OH-piperidyl, OH-phenyl-OH-piperidyl, carboxybenzoyl piperidine and depiperidyl analogues of mazapertine as major metabolites.

Biotransformation of an antihypertensive arylalkylamine analogue in the rat

1. The excretion and metabolism of N-[2-(3,4-dimethoxyphenyl)ethyl]-5-methoxy-N,alpha-dimethyl-2-(phenyl ethynyl) benzenepropanamine (RWJ-26240) in the Wistar rat has been investigated after a single oral dose of 14C-RWJ-26240 (50 mg/kg free base). 2. Plasma samples were obtained for 24 h after dosing and urine and faecal samples were collected over 8 days, and they accounted for 0.9 and 96% of the dose, respectively. 3. Representative samples of plasma, urine and faecal samples were purified for metabolite isolation and identification using HPLC, tlc, mass spectra (CI and EI), 1H-NMR and derivatization. 4. Unchanged RWJ-26240 plus 11 metabolites were identified and accounted for > 80% of the sample radioactivity. 5. Four metabolic pathways for RWJ-26240 are proposed; namely (1) N-demethylation, (2) O-demethylation, (3) phenyl hydroxylation and (4) N-dealkylation. Pathways 1-3 appeared to be quantitatively more important.

Metabolic fate of the hypoglycemic agent pirogliride in laboratory animals and humans

Metabolism of the hypoglycemic agent, pirogliride, was investigated in the rat, dog monkey and human. Unchanged pirogliride plus six metabolites were isolated and identified using solvent extraction, HPLC and CI and EI-MS from urine and fecal samples. Pirogliride was metabolized in man to a small extent by oxidation of the 4-position of the phenyl ring. The monkey metabolized pirogliride mainly by oxidation of the pyrrolidine rings, while oxidation of the phenyl ring was the minor pathway. In contrast to the monkey, the rat metabolized pirogliride primarily by oxidation of the phenyl ring. The dog showed a balance of oxidation between the phenyl and pyrrolidine rings.

Excretion and metabolism of the antihypertensive agent, RWJ-26240 (McN-5691) in dogs

The excretion and metabolism of a 2-ethynylbenzenealkanamine analog, antihypertensive RWJ-26240 (McN-5691), in beagle dogs was investigated. Recoveries of total radioactivity in urine and feces in the 7 days after oral administration of 14C-RWJ-26240 (6 mg/kg dose) were 2.8% and 96.8% of the radioactive dose, respectively. Representative plasma, urine, and fecal samples were pooled and purified for metabolite profiling, isolation, and identification. Unchanged RWJ-26240 (<19% of the dose) plus 12 metabolites were isolated and identified from these samples using chromatography (TLC, HPLC), spectroscopy (NMR, MS), and derivatization techniques. Unchanged RWJ-26240 plus identified metabolites accounted for >75% of the sample radioactivity in plasma and feces. The formation of RWJ-26240 metabolites can be depicted by the following proposed pathways: 1) N-demethylation, 2) O-demethylation, 3) phenyl hydroxylation, and 4) N-dealkylation. The first three pathways appeared to be quantitatively important steps which led to the production of four major metabolites (each >5% of the sample radioactivity). RWJ-26240 was extensively metabolized in the dog, and fecal excretion was the major route of elimination of RWJ-26240 and its metabolites.

Synthesis of hydroxylated derivatives of topiramate, a novel antiepileptic drug based on D-fructose: investigation of oxidative metabolites

To corroborate the structures of two monohydroxylated metabolites of topiramate (1), we synthesized four monosaccharide derivatives from D-fructose: 4,5-O-[(1R)- and 4,5-O-[(1S)-1-hydroxymethylethylidene]-2,3-O-isopropylidene-beta-D -fructopyranose sulfamates (2a and 2b); 2,3-O-[(1R)- and 2,3-O-[(1R)-1-hydroxymethylethylidene]-4,5-O-isopropylidene-beta-D -fructopyranose sulfamates (3a and 3b). The route to 2a and 2b was brief and straightforward, while that to 3a and 3b was more involved. In the latter case, the D-fructose bis-acetal 10 was benzylated and converted to a monoacetal dibenzoate (14) (50% yield), which was then transacetalized to give a mixture of 4,5-dibenzoyl-2,3-O-[(1R)- and 4,5-dibenzoyl-2,3-O-[(1S)-1-benzyloxymethylethylidene]- beta-D-fructopyranose (16a and 16b) (22%). The individual diastereomers were separated and processed via ester saponification, acetonation, sulfamoylation, and hydrogenolysis into 3a (36%) and 3b (27%). Structure 2b was confirmed for one oxidative metabolite, but the other metabolite was found not to correspond with either 2a, 3a, or 3b. On the basis of CI-MS and 1H NMR data, a (2-hydroxy-1,4-dioxano)pyran structure, 4, is proposed for this unidentified metabolite.

Unexpected antinociceptive effect of the N-oxide (RWJ 38705) of tramadol hydrochloride

N-Oxides of centrally acting analgesics generally have minimal analgesic activity. However, the N-oxide of tramadol produced dose-related, long-lasting antinociception in the mouse abdominal irritant, 48 degrees C hot-plate, 55 degrees C hot-plate, and tail-flick tests (ED50 = 15.5, 84.7, 316.4 and 138.2 mg/kg, p.o., respectively). Tramadol N-oxide (T-N-O) (RWJ 38705) was also antinociceptive in the 51 degrees C hot-plate test in male (ED50 = 63.2 mg/kg, i.p.) and female (ED50 = 39.9 mg/kg, i.p.) rats. A characteristic feature of T-N-O was an extended duration of action in these tests (4-5 h). T-N-O had negligible affinity for opioid mu (Ki = 38.5 microM) delta. or kappa receptors (Ki > 100 microM) and, in contrast to tramadol, was essentially devoid of norepinephrine or serotonin neuronal reuptake inhibitory activity (Ki > 100 microM). However, T-N-O displayed tramadol-like characteristics in vivo. There were also significant amounts of tramadol in plasma after T-N-O administration, and the levels resulting from equal oral doses of T-N-O and tramadol were the same, suggesting that the conversion of T-N-O to tramadol was rapid and essentially quantitative. T-N-O was not readily metabolized to tramadol in rat hepatic S9 fraction (< 2%), implying that the conversion might occur in the gastrointestinal tract. Taken together, the results suggest that T-N-O acts as a prodrug for tramadol. T-N-O could offer the clinical benefits of an extended duration of action and a "blunted" plasma concentration spike, possibly leading to an enhanced side-effect profile.

Biotransformation of linogliride, a hypoglycemic agent in laboratory animals and humans

Following oral administration of linogliride, a hypoglycemic agent, to rat (50 mg kg-1), dog (30 mg kg-1), and man (100 mg per subject), plasma, urine, and fecal extract sample pools were obtained. Nine metabolites plus unchanged linogliride were isolated and identified. The number of metabolites identified were: rat (5), dog (9), and man (1). In each species, more than 78% of the administered dose was recovered in the urine pools. Identified metabolites were estimated to account for > 82% of the total amounts of drug-related sample in urine pools and > 50% in plasma and fecal extract pools. Formation of linogliride metabolites in the three species can be described by four proposed pathways: pyrrolidine hydroxylation, aromatic hydroxylation, morpholine hydroxylation, and imino-bond cleavage. Comparison of the proposed metabolic pathways among species reveals a similarity between rat and dog. In these two species, pyrrolidine hydroxylation was quantitatively the most important pathway, with 5-hydroxylinogliride and dominant hypoglycemic active metabolite in all sample pools. Further oxidation of 5-hydroxylinogliride resulted in the formation of five minor metabolites. The other three pathways appeared to be quantitatively unimportant. Metabolism of linogliride in man occurred to a very limited extent. More than 90% of the total linogliride-related material in plasma was the unchanged drug. Greater than 76% of the administered dose was excreted unchanged in the urine. Only 5-hydroxylinogliride was identified in minor amounts in human samples.

In vitro and in vivo metabolism of the antianxiolytic agent fenobam in the rat

Fenobam [(Fn); N-(3-chlorophenyl)-N-(4,5-dihydro-1-methyl-4-oxo-1H-imidazole-2-yl)urea] sulfate is a novel agent with potent anxiolytic activity in rats. [14C]Fn sulfate was administered as an oral solution (250 mg/kg) to male Wistar rats, and 52% of the administered dose was excreted in urine (0-5 days). In vitro metabolism of Fn was studied by incubating [14C]Fn with rat hepatic 9000 x g supernatant preparations. Unchanged Fn and a total of six metabolites were isolated, quantified, and identified from the urine and liver 9000 x g supernatant samples by column chromatography; TLC; UV, IR, and NMR spectroscopy; MS; and comparison with synthetic samples. Four metabolic pathways for Fn are proposed: (1) hydroxylation at the phenyl ring to form 4-hydroxyphenyl-Fn, a major pathway in vivo (12% of the sample radioactivity) but a minor pathway in vitro (4% of the sample radioactivity); (2) hydroxylation at the creatinine ring to form 5-hydroxy-Fn (19%) of the sample radioactivity), a dominant pathway in vitro but not in vivo; (3) oxidative cleavage at the creatinine ring (loss of a ketene unit), a minor pathway for Fn but an important pathway for 4-hydroxyphenyl-Fn in vivo; and (4) N-demethylation, a minor pathway for Fn in vivo.

In vivo biotransformation of fenoctimine in rat, dog and man

1. The metabolism of fenoctimine (Fn) was studied in rat, dog and man following administration of 14C-Fn sulphate. 2. Seventeen Fn metabolites were isolated by hplc and tlc from rat bile, dog bile, dog urine, human urine, human faecal extracts, and human plasma and identified using nmr and MS. 3. The identified metabolites accounted for 75% of total radioactivity in rat bile, 80% in dog bile, and 40% in dog urine samples. In man, 90% of the urinary, 70% of the faecal, and > 50% of the plasma total radioactivity were identified. 4. Three major pathways for Fn metabolism were proposed. These pathways involved imino-bond cleavage, aromatic hydroxylation and oxidation of the aliphatic chain. 5. The imino-bond cleavage pathway was dominant in all species. However, the other two pathways differed in quantitative importance among the species studied. 6. The aromatic hydroxylation pathway appeared to be the most important means of biotransformation of Fn in dog since all but two of the metabolites were formed by this route. 7. The aliphatic oxidation pathway appeared to be important to the biotransformation of Fn in man and produced three major metabolites.

Metabolism of xilobam in laboratory animals and man

1. Biotransformation and excretion of xilobam (Xm) were studied after single oral doses of Xm-14C in mouse, rat, dog and man. 2. Following oral administration of Xm-14C, recoveries of total 14C (0-24 h) in urine were > or = 78% of the dose in all species. 3. Xm and a total of 11 metabolites have been isolated and identified, which accounted for 30, 65, 21 and 49% of the total 14C in the urine samples from mouse, rat, dog and man, respectively. 4. Xm was sequentially oxidized at the pyrrolidine ring to form 5'-OH Xm and 5'-oxo Xm. Both metabolites were isolated from human plasma accounting for 61% of the radioactivity in the sample. 5'-OH Xm was also identified as a major in vitro metabolite in the 9000g supernatant from a rat liver homogenate preparation. 5. 5'-OH Xm was isolated from the urine of all species except rats. However, oxidation products of 5'-oxo Xm were also present. Oxidation at the phenyl (ph) ring and at the phCH3 group produced the corresponding 4-OHph and phCH2OH metabolites. Subsequent water addition at the 2-position of the pyrrolidine ring followed by cleavage and/or cyclization of the above metabolites resulted in six additional urinary metabolites.

Characterization and identification of the metabolites of fenoctimine using in vitro drug metabolizing systems

Fenoctimine sulphate (4-(diphenylmethyl)-1-[(octylimino)methyl]piperidine sulphate) and one of its metabolites, 1-formyl-4-(diphenylmethyl) piperidine (RWJ-34321), were incubated with a rat liver post-mitochondrial supernatant preparation and an NADPH generating system. The metabolites, 7-hydroxyoctyl fenoctimine and 7-oxoocytl fenoctimine were identified as in vitro oxidative metabolites of fenoctimine on the basis of mass spectrometry and thin layer chromatography in comparison to authentic samples. RWJ-34321, a third metabolite, was confirmed as a hydrolyzed product of fenoctimine on the same basis. In separate incubations with RWJ-34321, one metabolite (4-(diphenylmethyl)piperidine), was identified as an in vitro metabolite of RWJ-34321 by mass spectrometry and thin layer chromatography. Thus, the in vitro metabolism of fenoctimine by rat liver homogenates resulted in the oxidation of the aliphatic chain at the seven carbon, initially to an alcohol and then to a ketone. The metabolism of RWJ-34321 resulted in decarbonylation of the formyl carbon.

Disposition of bepridil in laboratory animals and man

1. The disposition and pharmacokinetics of bepridil (Bp) were studied in mouse, rat, rabbit, rhesus monkey, and man. Bp was essentially completely absorbed by all species. 2. Maximum plasma Bp concentrations were achieved within 2 h of drug administration. Linear but non-proportional, dose-related increases in the area under the curve (AUC) for plasma Bp vs. time were noted after increasing oral doses of Bp.HCl to rats (30-300 mg/kg) and monkeys (25-200 mg/kg). 3. Daily administration of Bp.HCl to rats (100 mg/kg per day for 15 days) and monkeys (200 mg/kg per day for 13 days) produced no statistically significant changes in Bp pharmacokinetic parameters. 4. Oral plasma clearance (CLp) of Bp was very low in man (ca. 0.93 l/h per kg) compared to experimental animals (14.8-63.8 l/h per kg). Terminal elimination half-lives were 1.5-2.0 h for mouse and rat, ca. 4.4 h for monkey and ca. 48 h for man. 5. Bp and a total of 12 metabolites were identified and quantified. Metabolite formation in the five species was adequately described by four interrelated pathways, namely, aromatic hydroxylation, followed by N-dealkylation, N-debenzylation, and N-acetylation. Metabolites produced by this pathway included 4-hydroxy-Bp, N-benzyl-4-aminophenol, 4-aminophenol, and N-acetyl-4-aminophenol. Comparison of the proposed pathways revealed qualitative similarity among species.

Metabolism of bepridil in laboratory animals and humans

The metabolism of bepridil was studied in the Swiss mouse, Sprague-Dawley rat, New Zealand rabbit, rhesus monkey, and healthy human. After oral administration of bepridil-14C-hydrochloride, recoveries of total radioactivity in urine and feces (7 days) were greater than or equal to 80% of the administered dose in all five species. Bepridil and 25 metabolites have been isolated by HPLC and TLC from representative plasma, urine, and fecal extract pools from all species and identified on the basis of TLC, HPLC, and mass spectrometry. The identified metabolites explained 60-99% of the total radioactivity in each sample for rabbit plasma, in which only 17% of the total radioactivity was characterized. Metabolic pathways involving oxidative reactions at seven sites on the bepridil molecule are proposed for each species. Metabolite formation in the five species is described by four interrelated pathways. The metabolic pathway involving aromatic hydroxylation followed by N-dealkylation, N-debenzylation, and N-acetylation was important in all species. Major metabolites produced by this pathway included 4-hydroxy(at N-phenyl)-bepridil (Ia), N-benzyl-4-amino-phenol (IV), and N-acetyl-4-aminophenol (Vy). Metabolite Ia was isolated in significant amounts (greater than or equal to 5% of sample) in all fecal and urine samples except rat urine. Metabolite IV was a major circulating metabolite in all species and a major urinary metabolite in humans. Metabolite Vy was present in significant quantities in urine in all species except rabbit. Other important pathways involved primary reactions such as iso-butyl hydroxylation, pyrrolidine ring oxidation, and N-debenzylation.(ABSTRACT TRUNCATED AT 250 WORDS)

The metabolism of zomepirac sodium. I. Disposition in laboratory animals and man

Zomepirac sodium (ZS) is an orally active, nonnarcotic, analgesic agent. The disposition and pharmacokinetics of zomepirac (Z) were studied in rats, mice, rabbits, hamsters, rhesus monkeys, and healthy human subjects. Z was rapidly and completely absorbed by all animal species and man. Dose-related linear increases in the area under the curve for plasma Z vs. time were noted after increasing po doses of ZS to mice (2.5--7.5 mg/kg), rats (0.5--10 mg/kg), and rhesus monkeys (5--40 mg/kg). Daily administration of ZS to rats (10 mg/kg/day for 10 days) caused no biologically significant changes in the pharmacokinetic profile for Z. Assessment of Z's absolute bioavailability in monkeys (10 mg/kg, iv vs. po) indicated that po doses of ZS were completely bioavailable (F = 1.12 +/- 0.40). Plasma clearance ranged from ca. 4.5 ml/min/kg for the female hamster, rhesus monkey, and man to as low as 0.30 ml/min/kg for rats, mice, and rabbits. Terminal elimination half-lives averaged 5.3--6.6 hr for mouse, 2.8--6.5 hr for rat, 2.5 hr for rabbit, 2.3 hr for hamster, 12.7--25.5 hr for rhesus monkey, and 4 hr for man. The major route of excretion for Z and its metabolites was via the kidneys for all animals and man with the balance appearing in feces. Biliary excretion was qualitatively observed in rhesus monkeys and quantitated in rats (23.6% of dose in 27 hr). Formation of the acyl glucuronide of Z was the major metabolic pathway in man and rhesus monkey, was substantial in the mouse, was very minor in the rat and rabbit, and was nonexistent in the hamster. Rat, mouse, and hamster hydroxylate the 4-methyl group on the pyrrole ring to give hydroxyzomepirac (a biologically inactive metabolite), a minor metabolite in man and nonexistent in the rhesus monkey. The rodents also cleave Z to form 4-chlorobenzoic acid and its conjugates, minor metabolites in man and rhesus monkey.