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1.
Biopharm Drug Dispos ; 45(2): 83-92, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38492211

RESUMO

AST-001 is a chemically synthesized inactive nitrogen mustard prodrug that is selectively cleaved to a cytotoxic aziridine (AST-2660) via aldo-keto reductase family 1 member C3 (AKR1C3). The purpose of this study was to investigate the pharmacokinetics and tissue distribution of the prodrug, AST-001, and its active metabolite, AST-2660, in mice, rats, and monkeys. After single and once daily intravenous bolus doses of 1.5, 4.5, and 13.5 mg/kg AST-001 to Sprague-Dawley rats and once daily 1 h intravenous infusions of 0.5, 1.5, and 4.5 mg/kg AST-001 to cynomolgus monkeys, AST-001 exhibited dose-dependent pharmacokinetics and reached peak plasma levels at the end of the infusion. No significant accumulation and gender differences were observed after 7 days of repeated dosing. In rats, the half-life of AST-001 was dose independent and ranged from 4.89 to 5.75 h. In cynomolgus monkeys, the half-life of AST-001 was from 1.66 to 5.56 h and increased with dose. In tissue distribution studies conducted in Sprague-Dawley rats and in liver cancer PDX models in female athymic nude mice implanted with LI6643 or LI6280 HepG2-GFP tumor fragments, AST-001 was extensively distributed to selected tissues. Following a single intravenous dose, AST-001 was not excreted primarily as the prodrug, AST-001 or the metabolite AST-2660 in the urine, feces, and bile. A comprehensive analysis of the preclinical data and inter-species allometric scaling were used to estimate the pharmacokinetic parameters of AST-001 in humans and led to the recommendation of a starting dose of 5 mg/m2 in the first-in-human dose escalation study.


Assuntos
Compostos de Mostarda Nitrogenada , Pró-Fármacos , Animais , Feminino , Camundongos , Ratos , Membro C3 da Família 1 de alfa-Ceto Redutase/efeitos dos fármacos , Macaca fascicularis , Camundongos Nus , Ratos Sprague-Dawley , Compostos de Mostarda Nitrogenada/farmacocinética , Aziridinas/farmacocinética , Relação Dose-Resposta a Droga
2.
3.
Am J Cancer Res ; 11(7): 3645-3659, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34354865

RESUMO

AST-3424/OBI-3424 (denoted by 3424) is a novel prodrug bis-alkylating agent activated by AKR1C3. AKR1C3 is overexpressed in many types of cancer, particularly in liver, non-small cell lung, gastric, renal and CRPC cancer. Currently 3424 is being studied in phase 1/2 clinical trials for the treatment of solid and hematologic cancers, and it represents potentially a novel, selective anti-cancer agent for multiple indications. In this study, AKR1C3-dependent activation of 3424 was investigated in vitro using recombinant human AKR1C3. AKR1C3-dependent cytotoxicity of 3424 was determined in a wide range of human cancer cell lines with different AKR1C3 expression levels. In addition, anti-tumor activity of 3424 was also investigated in a broad panel of CDX and PDX models. AKR1C3-dependent activation of prodrug 3424 was evident by monitoring the decrease of 3424 and generation of the active form, 2660. Kinetic analysis indicated that AKR1C3 exhibited higher catalytic efficiency towards 3424 compared to the physiological substrates. There was a strong correlation between 3424 cytotoxic potency and AKR1C3 expression. The racemic mixture induced DNA cross-linking in a concentration dependent manner. Tumor growth inhibition of 3424 was shown to be better than or comparable to the standard of care chemotherapy at clinically achievable doses as a single agent in various CDX models with high expression of AKR1C3, including liver HepG2, lung H460, castration-resistant prostate VCaP, gastric SNU-16, and kidney A498 cancer cell lines. The excellent anti-tumor efficacy of 3424 was further demonstrated in PDX models which have high level of AKR1C3 expression, but not in a model with low level of AKR1C3 expression. In the combination therapy, we showed that 3424 could enhance the efficacy of the standard care of chemotherapy in the CDX models. The results described here highlight that 3424 exhibits AKR1C3-dependent cytotoxicity in vitro and anti-tumor activity in vivo in a wide range of human cancer types, which support further development of 3424 as an anti-cancer agent for treating different types of cancers and the use of AKR1C3 as a biomarker to profile cancer patients and further guide patient selection for therapy with 3424.

4.
Clin Cancer Res ; 25(14): 4493-4503, 2019 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-31015346

RESUMO

PURPOSE: OBI-3424 is a highly selective prodrug that is converted by aldo-keto reductase family 1 member C3 (AKR1C3) to a potent DNA-alkylating agent. OBI-3424 has entered clinical testing for hepatocellular carcinoma and castrate-resistant prostate cancer, and it represents a potentially novel treatment for acute lymphoblastic leukemia (ALL). EXPERIMENTAL DESIGN: We assessed AKR1C3 expression by RNA-Seq and immunoblotting, and evaluated the in vitro cytotoxicity of OBI-3424. We investigated the pharmacokinetics of OBI-3424 in mice and nonhuman primates, and assessed the in vivo efficacy of OBI-3424 against a large panel of patient-derived xenografts (PDX). RESULTS: AKR1C3 mRNA expression was significantly higher in primary T-lineage ALL (T-ALL; n = 264) than B-lineage ALL (B-ALL; n = 1,740; P < 0.0001), and OBI-3424 exerted potent cytotoxicity against T-ALL cell lines and PDXs. In vivo, OBI-3424 significantly prolonged the event-free survival (EFS) of nine of nine ALL PDXs by 17.1-77.8 days (treated/control values 2.5-14.0), and disease regression was observed in eight of nine PDXs. A significant reduction (P < 0.0001) in bone marrow infiltration at day 28 was observed in four of six evaluable T-ALL PDXs. The importance of AKR1C3 in the in vivo response to OBI-3424 was verified using a B-ALL PDX that had been lentivirally transduced to stably overexpress AKR1C3. OBI-3424 combined with nelarabine resulted in prolongation of mouse EFS compared with each single agent alone in two T-ALL PDXs. CONCLUSIONS: OBI-3424 exerted profound in vivo efficacy against T-ALL PDXs derived predominantly from aggressive and fatal disease, and therefore may represent a novel treatment for aggressive and chemoresistant T-ALL in an AKR1C3 biomarker-driven clinical trial.


Assuntos
Membro C3 da Família 1 de alfa-Ceto Redutase/metabolismo , Antineoplásicos Alquilantes/farmacologia , Proliferação de Células , Sobrevivência Celular , Leucemia-Linfoma Linfoblástico de Células T Precursoras/tratamento farmacológico , Pró-Fármacos/farmacologia , Animais , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Feminino , Humanos , Macaca fascicularis , Camundongos , Camundongos Endogâmicos NOD , Camundongos SCID , Leucemia-Linfoma Linfoblástico de Células T Precursoras/metabolismo , Resultado do Tratamento , Ensaios Antitumorais Modelo de Xenoenxerto
5.
Eur J Drug Metab Pharmacokinet ; 40(1): 75-86, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24590312

RESUMO

This was a single dose mass balance and metabolite characterization study of the antimalarial agent pyronaridine. Six healthy male adults were administered a single oral dose of 720 mg pyronaridine tetraphosphate with 800 nCi of radiolabeled (14)C-pyronaridine. Urine and feces were continuously collected through 168 h post-dose, with intermittent 48 h collection periods thereafter through 2064 h post-dose. Drug recovery was computed for analyzed samples and interpolated for intervening time periods in which collection did not occur. Blood samples were obtained to evaluate the pharmacokinetics of total radioactivity and of the parent compound. Total radioactivity in urine, feces, and blood samples was determined by accelerator mass spectrometry (AMS); parent concentrations in blood were determined with LC/MS. Metabolite identification based on blood, urine, and feces samples was conducted using a combination of LC + AMS for identifying radiopeaks, followed by LC/MS/MS for identity confirmation/elucidation. The mean cumulative drug recovery in the urine and feces was 23.7 and 47.8 %, respectively, with an average total recovery of 71.5 %. Total radioactivity was slowly eliminated from blood, with a mean half-life of 33.5 days, substantially longer than the mean parent compound half-life of 5.03 days. Total radioactivity remained detectable in urine and feces collected in the final sampling period, suggesting ongoing elimination. Nine primary and four secondary metabolites of pyronaridine were identified. This study revealed that pyronaridine and its metabolites are eliminated by both the urinary and fecal routes over an extended period of time, and that multiple, varied pathways characterize pyronaridine metabolism.


Assuntos
Antimaláricos/farmacocinética , Naftiridinas/farmacocinética , Administração Oral , Adulto , Antimaláricos/administração & dosagem , Antimaláricos/sangue , Antimaláricos/urina , Biotransformação , Cromatografia Líquida , Fezes/química , Meia-Vida , Voluntários Saudáveis , Humanos , Masculino , Metabolômica/métodos , Pessoa de Meia-Idade , Naftiridinas/administração & dosagem , Naftiridinas/sangue , Naftiridinas/urina , Suíça , Espectrometria de Massas em Tandem/métodos
6.
J Drug Assess ; 3(1): 20-7, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-27536450

RESUMO

OBJECTIVE: Famotidine given at a dose of 80 mg/day is effective in preventing NSAID-induced gastropathy. The aim of this proof of concept study was to compare twice a day (BID) vs 3-times a day (TID) administration of this total dose of famotidine on intragastric pH in healthy volunteers. RESEARCH DESIGN AND METHODS: Two analyses were undertaken: (1) a 13 subject controlled cross-over 24-h intragastric pH evaluation of the BID and TID administration of 80 mg/day of famotidine, as well as measures for drug accumulation over 5 days (EudraCT, number 2006-002930-39); and (2) a pharmacokinetic (PK)/pharmacodynamic (PD) model which predicted steady-state famotidine plasma concentrations and pH of the two regimens. RESULTS: For the cross-over study, gastric pH was above 3.5 for a mean of 20 min longer for TID dosing compared to BID dosing on Day 1. On Day 5, the mean time above this threshold was higher with the BID regimen by ∼25 min. For pH 4, subjects' gastric pH was above this pH value for a mean of 25 min longer for TID dosing compared to BID dosing on Day 1. For Day 5, the pH was above 4 for ∼45 min longer with the TID regimen as compared with the BID regimen. The mean 24-h gastric pH values when taken in the upright position trended higher for the TID dosing period compared to the BID regimen on Day 1. The steady-state simulation model indicated that, following TID dosing, intragastric pH will be above 3 for 24 h vs 16 h for the BID regimen. There was no evidence for plasma accumulation of famotidine with TID dosing as compared to BID dosing from either analysis. CONCLUSION: The data indicate that overall more time is spent above the acidic threshold pH values when 80 mg/day of famotidine is administered TID vs BID. Key limitations included small study size with a short duration and lack of a baseline examination, but was compensated for by the cross-over and PK/PD modeling design. Although most of the comparisons in this proof of concept study were not statistically significant these results have important implications for future research on gastric acid lowering agents used for the prevention of NSAID-induced gastropathy.

7.
Antimicrob Agents Chemother ; 57(12): 5889-900, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24041884

RESUMO

Despite the important role of the antimalarial artesunate and its active metabolite dihydroartemisinin (DHA) in malaria treatment efforts, there are limited data on the pharmacokinetics of these agents in pediatric patients. This study evaluated the effects of body size and gender on the pharmacokinetics of artesunate-DHA using data from pediatric and adult malaria patients. Nonlinear mixed-effects modeling was used to obtain a base model consisting of first-order artesunate absorption and one-compartment models for artesunate and for DHA. Various methods of incorporating effects of body size descriptors on clearance and volume parameters were tested. An allometric scaling model for weight and a linear body surface area (BSA) model were deemed optimal. The apparent clearance and volume of distribution of DHA obtained with the allometric scaling model, normalized to a 38-kg patient, were 63.5 liters/h and 65.1 liters, respectively. Estimates for the linear BSA model were similar. The 95% confidence intervals for the estimated gender effects on clearance and volume parameters for artesunate fell outside the predefined no-relevant-clinical-effect interval of 0.75 to 1.25. However, the effect of gender on apparent DHA clearance was almost entirely contained within this interval, suggesting a lack of an influence of gender on this parameter. Overall, the pharmacokinetics of artesunate and DHA following oral artesunate administration can be described for pediatric patients using either an allometric scaling or linear BSA model. Both models predict that, for a given artesunate dose in mg/kg of body weight, younger children are expected to have lower DHA exposure than older children or adults.


Assuntos
Antimaláricos/farmacocinética , Artemisininas/farmacocinética , Modelos Estatísticos , Plasmodium falciparum/efeitos dos fármacos , Administração Oral , Adulto , Fatores Etários , Antimaláricos/farmacologia , Artemisininas/metabolismo , Artemisininas/farmacologia , Artesunato , Tamanho Corporal , Peso Corporal , Criança , Pré-Escolar , Simulação por Computador , Esquema de Medicação , Cálculos da Dosagem de Medicamento , Feminino , Meia-Vida , Humanos , Malária Falciparum/tratamento farmacológico , Malária Falciparum/microbiologia , Masculino , Testes de Sensibilidade Microbiana , Plasmodium falciparum/crescimento & desenvolvimento , Fatores Sexuais
8.
Cancer Chemother Pharmacol ; 71(2): 523-30, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-23228990

RESUMO

PURPOSE: This phase I trial was initiated to evaluate the safety, pharmacokinetics (PK) and maximum tolerated dose (MTD) of the glycolytic inhibitor, 2-deoxy-D-glucose (2DG) in combination with docetaxel, in patients with advanced solid tumors. METHODS: A modified accelerated titration design was used. 2DG was administered orally once daily for 7 days every other week starting at a dose of 2 mg/kg and docetaxel was administered intravenously at 30 mg/m(2) for 3 of every 4 weeks beginning on day 1 of week 2. Following the completion of dose escalation, cohorts of patients were then treated with 2DG for 21 days or every day of each 4-week cycle for up to 12 cycles. RESULTS: Thirty-four patients were enrolled: 21 on every other week, 6 on a 21 of 28-day cycle and 7 on the continuous 2DG dosing schedule. There were no dose-limiting toxicities which met the MTD criteria. The most common adverse events were fatigue, sweating, dizziness and nausea mimicking the hypoglycemic symptoms expected from 2DG administration. Therefore, 63 mg/kg was selected as the clinically tolerable dose. The most significant adverse effects noted at 63-88 mg/kg doses were reversible hyperglycemia (100 %), gastrointestinal bleeding (6 %) and reversible grade 3 QTc prolongation (22 %). Eleven patients (32 %) had stable disease, 1 patient (3 %) partial response and 22 patients (66 %) progressive disease as their best response. There was no PK interaction between 2DG and docetaxel. CONCLUSION: The recommended dose of 2DG in combination with weekly docetaxel is 63 mg/kg/day with tolerable adverse effects.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Desoxiglucose/administração & dosagem , Desoxiglucose/uso terapêutico , Neoplasias/tratamento farmacológico , Taxoides/administração & dosagem , Taxoides/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Glicemia/análise , Desoxiglucose/efeitos adversos , Docetaxel , Eletrocardiografia/efeitos dos fármacos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Taxoides/efeitos adversos
9.
Am J Trop Med Hyg ; 86(3): 489-495, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22403324

RESUMO

A multiple dose, parallel group study was conducted to assess for a drug-drug interaction between the pyronaridine/artesunate (PA) combination antimalarial and ritonavir. Thirty-four healthy adults were randomized (1:1) to receive PA for 3 days or PA with ritonavir (100 mg twice daily for 17 days, PA administered on Days 8-10). Pharmacokinetic parameters for pyronaridine, artesunate, and its active metabolite dihydroartemisinin (DHA) were obtained after the last PA dose and for ritonavir on Days 1 and 10. Ritonavir coadministration did not markedly change pyronaridine pharmacokinetics but resulted in a 27% increase in artesunate area under the curve (AUC) and a 38% decrease in DHA AUC. Ritonavir exposure was increased 3.2-fold in the presence of PA. The only relevant safety observations were increases in liver enzymes, only reaching a clinically significant grade in the PA + ritonavir arm. It was concluded that coadministered ritonavir and PA interact to alter exposure to artesunate, DHA, and ritonavir itself.


Assuntos
Antimaláricos/administração & dosagem , Artemisininas/administração & dosagem , Inibidores da Protease de HIV/administração & dosagem , Naftiridinas/administração & dosagem , Ritonavir/administração & dosagem , Adolescente , Adulto , Antimaláricos/farmacocinética , Área Sob a Curva , Artemisininas/farmacocinética , Artesunato , Interações Medicamentosas , Feminino , Inibidores da Protease de HIV/farmacocinética , Humanos , Masculino , Pessoa de Meia-Idade , Naftiridinas/farmacocinética , Ritonavir/farmacocinética , Adulto Jovem
10.
Xenobiotica ; 42(7): 687-700, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22352389

RESUMO

The metabolism and excretion of a hypoxically activating prodrug for the treatment of cancer, TH-302, were studied in beagle dogs following intravenous administration of 20 mg/kg (14)C-TH-302. TH-302 was extensively metabolized with total recovery of 75.1%, with 47.5% and 25.3% excreted through the urine and through the bile into the feces, respectively. The three TH-302 metabolites in plasma were: DM7, a conjugate of TH-302 with glutathione replacing a bromine atom; DM5, a hydrolysis product of DM7 with loss of the glutamic acid moiety; and DM6, a hydrolysis product of DM5 with loss of the glycine moiety. DM6 and TH-302 were the major radioactive components in plasma and accounted for 69.8% and 27.3% of the total AUC, respectively. The major metabolite in urine was DM6, which accounted for 22.7% of the administered dose. Two other metabolites identified in urine were: DM3, a dicysteine conjugate of TH-302; and DM4, which was formed by hydrolysis and loss of the 1-methyl-2-nitro-imidazol-5-yl methoxy moiety, followed by oxidation on the cysteinyl ethylamine moiety. DM1 and DM2 in urine accounted for 6.50 and 7.76% of administered dose and were not identified. DM1 was the only fecal metabolite. Further investigations are required to completely characterize the metabolism of TH-302.


Assuntos
Nitroimidazóis/metabolismo , Mostardas de Fosforamida/metabolismo , Animais , Área Sob a Curva , Cães , Etilaminas/metabolismo , Fezes/química
11.
Cancer Chemother Pharmacol ; 69(3): 643-54, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21964906

RESUMO

PURPOSE: To characterize the pharmacokinetics of the prodrug, TH-302, and its active metabolite, bromo-IPM (Br-IPM), in nonclinical species. METHODS: TH-302 was administered in single oral, intraperitoneal and intravenous bolus doses to mice, rats, dogs and monkeys as well as in acute and chronic safety studies in rats and dogs as a 30-min intravenous infusion given once a week for 3 weeks. Assessments were made using liquid chromatography-tandem mass spectrometry. RESULTS: TH-302 was extensively distributed with high systemic clearance exceeding hepatic plasma flow in all species studied, resulting in half-lives ranging between 8 min (mice) and over 4 h (rats). In rats, TH-302 exhibited linear kinetics following intravenous administration and good oral bioavailability. In acute and chronic safety studies, there was no accumulation of TH-302 following once weekly dosing for 3 weeks in the rat and dog. Br-IPM plasma concentrations were a small fraction of the TH-302 plasma concentrations with significantly smaller percentages present in dogs than in rats. Allometric scaling predicted that the systemic clearance and steady-state volume of distribution in humans would be 38.8 l/h/m(2) and 34.3 l/m(2), respectively, resulting in a terminal elimination half-life of about 36 min. These values were similar to those observed in patients with solid tumors (27.1 l/h/m(2), 23.5 l/m(2) and 47 min). CONCLUSIONS: TH-302 exhibited good safety, efficacy and pharmacokinetic properties in nonclinical species, translating into favorable properties in humans.


Assuntos
Hipóxia/metabolismo , Nitroimidazóis/farmacocinética , Mostardas de Fosforamida/farmacocinética , Pró-Fármacos/farmacocinética , Administração Oral , Animais , Cães , Avaliação Pré-Clínica de Medicamentos , Feminino , Meia-Vida , Humanos , Infusões Intravenosas , Injeções Intraperitoneais , Injeções Intravenosas , Macaca fascicularis , Masculino , Camundongos , Camundongos Endogâmicos , Camundongos Nus , Estrutura Molecular , Nitroimidazóis/administração & dosagem , Nitroimidazóis/toxicidade , Mostardas de Fosforamida/administração & dosagem , Mostardas de Fosforamida/toxicidade , Valor Preditivo dos Testes , Pró-Fármacos/administração & dosagem , Pró-Fármacos/toxicidade , Ratos , Ratos Sprague-Dawley , Especificidade da Espécie , Distribuição Tecidual
12.
Xenobiotica ; 42(4): 372-88, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22004352

RESUMO

The metabolism, pharmacokinetics and excretion of a hypoxically activating prodrug developed for the treatment of cancer, TH-302, were studied in rats following intravenous administration of 50 mg/kg [(14)C]-TH-302. The pharmacokinetics of TH-302 was characterized by a short half-life of 12.3 min, a high clearance of 2.29 L/h/kg and a volume of distribution of 0.627 L/kg. In intact and bile duct-cannulated rats, TH-302 was extensively metabolized with total recovery in excreta of 68.1% and 85.8%, respectively, with equal amounts excreted through urine and bile. Quantitative whole body autoradiography showed rapid distribution of [(14)C]-TH-302 associated radioactivity with the highest concentrations in the kidney and small intestinal content, suggesting significant biliary excretion and/or gut secretion. TH-302 was metabolized via (i) hydrolysis to form 2-bromoethyl amine RM3 (7.5%); (ii) monoglutathione conjugation and subsequently to the mercapturic acid RM13 (7.5%); and (iii) diglutathione conjugation followed by hydrolysis to form the dicysteine conjugate RM5 (6.5%). A large percentage (19.7%) of the dose in the excreta was associated with unidentified polar metabolites RM1 and RM2. TH-302 was the predominant circulating component in plasma and the two major metabolites in plasma were the cysteine conjugate RM8 and mercapturic acid RM13.


Assuntos
Nitroimidazóis/farmacocinética , Mostardas de Fosforamida/farmacocinética , Pró-Fármacos/farmacocinética , Animais , Bile/metabolismo , Hipóxia Celular , Meia-Vida , Masculino , Nitroimidazóis/toxicidade , Mostardas de Fosforamida/toxicidade , Ratos , Ratos Sprague-Dawley , Distribuição Tecidual
13.
Malar J ; 10: 263, 2011 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-21914160

RESUMO

Artesunate (AS) is a clinically versatile artemisinin derivative utilized for the treatment of mild to severe malaria infection. Given the therapeutic significance of AS and the necessity of appropriate AS dosing, substantial research has been performed investigating the pharmacokinetics of AS and its active metabolite dihydroartemisinin (DHA). In this article, a comprehensive review is presented of AS clinical pharmacokinetics following administration of AS by the intravenous (IV), intramuscular (IM), oral or rectal routes. Intravenous AS is associated with high initial AS concentrations which subsequently decline rapidly, with typical AS half-life estimates of less than 15 minutes. AS clearance and volume estimates average 2 - 3 L/kg/hr and 0.1 - 0.3 L/kg, respectively. DHA concentrations peak within 25 minutes post-dose, and DHA is eliminated with a half-life of 30 - 60 minutes. DHA clearance and volume average between 0.5 - 1.5 L/kg/hr and 0.5 - 1.0 L/kg, respectively. Compared to IV administration, IM administration produces lower peaks, longer half-life values, and higher volumes of distribution for AS, as well as delayed peaks for DHA; other parameters are generally similar due to the high bioavailability, assessed by exposure to DHA, associated with IM AS administration (> 86%). Similarly high bioavailability of DHA (> 80%) is associated with oral administration. Following oral AS, peak AS concentrations (Cmax) are achieved within one hour, and AS is eliminated with a half-life of 20 - 45 minutes. DHA Cmax values are observed within two hours post-dose; DHA half-life values average 0.5 - 1.5 hours. AUC values reported for AS are often substantially lower than those reported for DHA following oral AS administration. Rectal AS administration yields pharmacokinetic results similar to those obtained from oral administration, with the exceptions of delayed AS Cmax and longer AS half-life. Drug interaction studies conducted with oral AS suggest that AS does not appreciably alter the pharmacokinetics of atovaquone/proguanil, chlorproguanil/dapsone, or sulphadoxine/pyrimethamine, and mefloquine and pyronaridine do not alter the pharmacokinetics of DHA. Finally, there is evidence suggesting that the pharmacokinetics of AS and/or DHA following AS administration may be altered by pregnancy and by acute malaria infection, but further investigation would be required to define those alterations precisely.


Assuntos
Antimaláricos/farmacocinética , Artemisininas/farmacocinética , Administração Oral , Administração Retal , Antimaláricos/administração & dosagem , Artemisininas/administração & dosagem , Artesunato , Disponibilidade Biológica , Meia-Vida , Humanos , Injeções Intramusculares , Injeções Intravenosas , Taxa de Depuração Metabólica , Fatores de Tempo
14.
J Med Chem ; 54(6): 1715-23, 2011 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-21341674

RESUMO

14-Aminocamptothecins were synthesized in good yields by treating camptothecin (1a) and 7-ethylcamptothecin (1b) with 90% fuming nitric acid either neat or in acetic anhydride and then followed by reduction of the resulting 14-nitrocamptothecins (2). 14-Aminocamptothecin (3a) and 7-ethyl-14-aminocamptothecin (3b) demonstrated excellent cytotoxic potency against human tumor cell lines in vitro, and they are not substrates for any of the major clinically relevant efflux pumps (MDR1, MRP1, and BCRP). 3a and 3b showed similar cytotoxicity against human and mouse bone marrow progenitor cells. This is in contrast to many camptothecin analogues, which are substrates for efflux pumps and are dramatically more toxic to human marrow cells relative to murine. 3a and 3b demonstrated significant brain penetration when dosed orally in mice. 3b showed significantly better efficacy relative to topotecan when dosed orally in the three ectopic xenograft models, H460, HT29, and PC-3. On the basis of its favorable in vitro and in vivo profile, 3b warrants future development.


Assuntos
Antineoplásicos/síntese química , Camptotecina/análogos & derivados , Camptotecina/síntese química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Transportadores de Cassetes de Ligação de ATP/metabolismo , Administração Oral , Animais , Antineoplásicos/farmacocinética , Antineoplásicos/farmacologia , Células da Medula Óssea/efeitos dos fármacos , Encéfalo/metabolismo , Camptotecina/farmacocinética , Camptotecina/farmacologia , Linhagem Celular Tumoral , Resistencia a Medicamentos Antineoplásicos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Masculino , Camundongos , Camundongos Nus , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Proteínas de Neoplasias/metabolismo , Transplante de Neoplasias , Especificidade da Espécie , Estereoisomerismo , Relação Estrutura-Atividade , Transplante Heterólogo
15.
Am J Clin Oncol ; 33(2): 111-6, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19687729

RESUMO

OBJECTIVES: A dose-escalation study of glufosfamide plus gemcitabine showed that the combination could be administered safely at full doses. The purpose of this phase II study was to evaluate the safety and efficacy of this combination in chemotherapy-naive pancreatic adenocarcinoma. METHODS: Eligible patients had metastatic and/or locally advanced pancreatic adenocarcinoma, Karnofsky performance status >or=70, creatinine clearance (CrCL) >or=60 mL/min, and acceptable organ function. Patients received glufosfamide 4500 mg/m intravenous on day 1 and gemcitabine 1000 mg/m intravenous on Days 1, 8, and 15 of every 28-day cycle. The primary end point was response rate. RESULTS: Twenty-nine patients were enrolled; 14 male, median age 58 years. Twenty-three (79%) patients had distant metastases. Median cycles on treatment was 4 (range: 1-18+). Of 28, 5 (18%; 95% CI: 6%-37%) patients had a confirmed partial response (median duration: 8.4 months) and 1 had an unconfirmed partial response. Eleven patients (39%) had stable disease. Median progression-free survival was 3.7 months, median overall survival was 6 months, and 1-year survival was 32%. Grade 3/4 neutropenia occurred in 23 (79%) patients and grade 3/4 thrombocytopenia in 10 (34%) patients. The CrCL fell below 60 mL/min in 10 of 27 (37%) patients. Renal failure occurred in 4 patients. Decrease in CrCL was correlated with glufosfamide and isophosphoramide mustard pharmacokinetic area under the curve. CONCLUSIONS: The combination of glufosfamide plus gemcitabine is active in pancreatic cancer; however, hematologic and renal toxicity were pronounced. Alternative dosing of glufosfamide plus gemcitabine should be explored.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/secundário , Adulto , Idoso , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Feminino , Glucose/análogos & derivados , Humanos , Ifosfamida/análogos & derivados , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neoplasias Pancreáticas/patologia , Mostardas de Fosforamida/administração & dosagem , Segurança , Taxa de Sobrevida , Resultado do Tratamento , Gencitabina
16.
Cancer Chemother Pharmacol ; 61(6): 1019-26, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-17661038

RESUMO

PURPOSE: To evaluate safety and pharmacokinetics and to establish the maximum tolerated dose of glufosfamide when administered in combination with gemcitabine in advanced solid tumors. METHODS: This Phase 1 dose-escalation study evaluated the combination of glufosfamide + gemcitabine in patients with advanced solid tumors. Cohorts of three to six patients were treated with glufosfamide doses from 1,500 to 4,500 mg/m(2) i.v. over 4 h on Day 1 and gemcitabine 1,000 mg/m(2) i.v. over 30 min on Days 1, 8 and 15 of every 28-day cycle. Detailed PK sampling was performed on days 1 and 8 of the first two cycles. RESULTS: Nineteen patients were enrolled. Two patients had dose-limiting toxicity: Grade 3 fatigue at 2,500 mg/m(2) and Grade 4 thrombocytopenia at 4,500 mg/m(2). Five patients completed six cycles and one patient remained on study for ten cycles. Two patients discontinued for adverse events. Grade 3/4 neutropenia and thrombocytopenia occurred in seven patients and five patients, respectively. The CrCL fell below 60 mL/min in two patients. There was one unconfirmed partial response and 10 of 19 (52.6%) patients had stable disease or better at 8 weeks and three patients had continuing stable disease at 24 weeks. Pharmacokinetic analyses suggest no interaction between glufosfamide and gemcitabine. CONCLUSION: Phase I data indicate that full dose glufosfamide (4,500 mg/m(2)) can be given safely in combination with gemcitabine. A Phase II study in patients with pancreatic adenocarcinoma is ongoing.


Assuntos
Adenocarcinoma/tratamento farmacológico , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Neoplasias Pancreáticas/tratamento farmacológico , Adenocarcinoma/patologia , Adulto , Idoso , Antimetabólitos Antineoplásicos/administração & dosagem , Antimetabólitos Antineoplásicos/efeitos adversos , Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/efeitos adversos , Área Sob a Curva , Desoxicitidina/administração & dosagem , Desoxicitidina/análogos & derivados , Feminino , Glucose/análogos & derivados , Meia-Vida , Doenças Hematológicas/induzido quimicamente , Doenças Hematológicas/epidemiologia , Humanos , Ifosfamida/análogos & derivados , Masculino , Pessoa de Meia-Idade , Neoplasias Pancreáticas/patologia , Mostardas de Fosforamida/administração & dosagem , Gencitabina
17.
Br J Clin Pharmacol ; 65(1): 51-9, 2008 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-17662090

RESUMO

AIMS: Oral L-arginine supplementation has been used in several studies to improve endothelium-dependent, nitric oxide (NO)-mediated vasodilation. L-Arginine treatment is hampered by extensive presystemic elimination due to intestinal arginase activity. In contrast, L-citrulline is readily absorbed and at least in part converted to L-arginine. The aim of our study was to assess this metabolic conversion and its subsequent pharmacodynamic effects. METHODS: In a double-blind, randomized, placebo-controlled cross-over study, 20 healthy volunteers received six different dosing regimes of placebo, citrulline, and arginine. Pharmacokinetic parameters (C(max), T(max), C(min), AUC) were calculated after 1 week of oral supplementation. The ratio of plasma L-arginine over asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide synthase (arginine/ADMA ratio), urinary cyclic guanosine monophosphate (cGMP) and nitrate excretion rates, and flow-mediated vasodilation (FMD) was measured to assess pharmacodynamic effects. RESULTS: L-Citrulline dose-dependently increased AUC and C(max) of plasma L-arginine concentration more effectively than L-arginine (P < 0.01). The highest dose of citrulline (3 g bid) increased the C(min) of plasma L-arginine and improved the L-arginine/ADMA ratio from 186 +/- 8 (baseline) to 278 +/- 14 [P < 0.01, 95% confidence interval (CI) 66, 121]. Moreover, urinary nitrate and cGMP were increased from 92 +/- 10 to 125 +/- 15 micromol mmol(-1) creatinine (P = 0.01, 95% CI 8, 58) and from 38 +/- 3.3 to 50 +/- 6.7 nmol mmol(-1) creatinine (P = 0.04, 95% CI 0.4, 24), respectively. No treatment improved FMD over baseline. However, pooled analysis of all FMD data revealed a correlation between the increase of arginine/ADMA ratio and improvement of FMD. CONCLUSION: Our data show for the first time that oral L-citrulline supplementation raises plasma L-arginine concentration and augments NO-dependent signalling in a dose-dependent manner.


Assuntos
Arginina/farmacocinética , Citrulina/farmacocinética , Óxido Nítrico Sintase/efeitos dos fármacos , Óxido Nítrico/metabolismo , Vasodilatação/efeitos dos fármacos , Administração Oral , Arginina/análogos & derivados , Arginina/metabolismo , Citrulina/farmacologia , Estudos Cross-Over , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placebos
18.
J Pharm Sci ; 93(9): 2214-21, 2004 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-15295782

RESUMO

R1481 is a sub-type selective muscarinic receptor antagonist with the potential treatment of overactive bladder. R1481 presents two challenges for drug development. The first is the viscous semi-solid nature of the active pharmaceutical ingredient (API). The second challenge is the poor oral bioavailability of this water soluble, metabolically stable compound due to low intestinal permeability, and the P-glycoprotein (P-gp) efflux mechanism. Vitamin E TPGS is reported by others to enhance bioavailability by increasing the solubility of active compounds and by inhibiting P-gp in the intestine. In this report, compatibility of R1481 in Capmul MCM-based formulations with and without vitamin E TPGS is summarized. Review of accelerated stability studies of oral formulations led to the identification of a soft gelatin capsule formulation using neat Capmul MCM as an acceptable formulation for Phase 1 clinical studies. Soft gelatin capsules (5 mg strength) were manufactured with and without the addition of vitamin E TPGS. Clinical data show that vitamin E TPGS does not improve systemic exposure of R1481 in humans.


Assuntos
Gelatina/sangue , Antagonistas Muscarínicos/sangue , Soluções Farmacêuticas/farmacocinética , Adulto , Animais , Biofarmácia , Cápsulas , Fenômenos Químicos , Química Farmacêutica , Físico-Química , Estudos Cross-Over , Avaliação Pré-Clínica de Medicamentos/métodos , Feminino , Gelatina/administração & dosagem , Gelatina/química , Humanos , Masculino , Pessoa de Meia-Idade , Antagonistas Muscarínicos/administração & dosagem , Antagonistas Muscarínicos/química , Soluções Farmacêuticas/administração & dosagem , Soluções Farmacêuticas/química , Suínos , Porco Miniatura , Vitamina E/administração & dosagem , Vitamina E/sangue , Vitamina E/química
19.
J Clin Virol ; 24(1-2): 67-77, 2002 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11744430

RESUMO

BACKGROUND: The oral formulation of ganciclovir is approved at a dose of 3.0 g/day for maintenance treatment of cytomegalovirus (CMV) retinitis following an initial induction course of intravenous (IV) anti-CMV therapy. Median time to progression of CMV retinitis is 12-20 days shorter with oral compared to IV ganciclovir maintenance, likely due to the limited oral bioavailability of ganciclovir. OBJECTIVES: We hypothesized that higher systemic drug exposures associated with increased doses of oral ganciclovir would be associated with increased efficacy. STUDY DESIGN: Maintenance treatment of CMV retinitis with higher than standard doses of oral ganciclovir (>3.0 g/day) was studied in 281 AIDS patients with previously treated, stable retinitis randomized to 3.0, 4.5 or 6.0 g/day oral, or 5 m/kg/day IV ganciclovir. Graders unaware of treatment assignments determined retinitis progression using fundus photographs. Vision, other ophthalmic measures and safety were assessed open-label. RESULTS: Median days to photographic progression were 41, 50, 57 and 70, respectively (P=0.052; 3.0 g vs. IV). Hazard ratios for progression relative to IV were 1.66, 1.28 and 1.19 (P=0.016 for 3.0 g). NONMEM-modeled estimates of average serum ganciclovir concentration area under the curve (AUC(0-24)) correlated best with time to progression (P=0.0019). Six grams per day oral ganciclovir was most similar in efficacy to IV, although broad confidence intervals prevented a conclusive comparison. Patients receiving oral ganciclovir had a lower frequency of sepsis and IV catheter events. CONCLUSIONS: This study suggests that the efficacy of ganciclovir for the maintenance treatment of CMV retinitis improves with increasing total drug exposure (measured as average serum concentration AUC(0-24)). All four regimens of ganciclovir were reasonably well tolerated, with safety profiles similar to what has been reported in prior work.


Assuntos
Infecções Oportunistas Relacionadas com a AIDS/tratamento farmacológico , Antivirais/uso terapêutico , Retinite por Citomegalovirus/tratamento farmacológico , Ganciclovir/uso terapêutico , Infecções Oportunistas Relacionadas com a AIDS/complicações , Síndrome da Imunodeficiência Adquirida/complicações , Administração Oral , Adulto , Retinite por Citomegalovirus/complicações , Retinite por Citomegalovirus/metabolismo , Progressão da Doença , Feminino , Ganciclovir/efeitos adversos , Humanos , Injeções Intravenosas , Masculino , Análise de Sobrevida , Resultado do Tratamento , Acuidade Visual
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