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1.
J Nutr ; 148(11): 1704-1715, 2018 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-30203029

RESUMEN

Background: A self-micro-emulsifying delivery system (SMEDS) promotes spontaneous emulsification of omega-3 (n-3) ethyl esters (EEs) into microdroplets in the stomach. Objective: The objective was to compare the effect of SMEDS preparations of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) EEs with standard EEs on EPA and DHA concentrations in the bloodstream after a single dose and repeated daily dosing. Methods: Eighty healthy subjects aged 18-65 y were randomly assigned to SMEDS-EPA or EE-EPA (both providing more EPA than DHA) or SMEDS-DHA or EE-DHA (both providing more DHA than EPA). They consumed a single dose (1.23-1.33 g EPA+DHA) without a meal, and EPA and DHA were measured in plasma over the following 24 h. Participants continued to take a single dose each morning before breakfast for 12 wk. EPA and DHA were measured in fasting plasma, mononuclear cells (MNCs), and RBCs. Results: EPA and DHA were higher in plasma in the 24 h after a single dose of SMEDS-EPA or SMEDS-DHA than after consuming the comparator EE (P < 0.001 for both). Compared with the EE form, repeated daily dosing of the SMEDS formulations for 12 wk resulted in higher concentrations of EPA and DHA in plasma (P = 0.086 and 0.005, respectively), MNCs (P < 0.001 and 0.020, respectively), and RBCs (both P < 0.001). The omega-3 index increased over 12 wk from 5.1 ± 0.9 to 7.9 ± 0.9 in the SMEDS-EPA group, from 5.3 ± 1.1 to 9.0 ± 1.2 in the SMEDS-DHA group, from 4.8 ± 0.8 to 6.4 ± 0.9 in the EE-EPA group, and from 5.2 ± 0.9 to 7.2 ± 1.0 in the EE-DHA group (all P < 0.001). The omega-3 index was higher with SMEDS than with the comparator EE at 12 wk (both P < 0.001). Conclusions: Compared with standard EEs, a SMEDS results in greater incorporation of EPA and DHA into blood pools after a single dose and with repeated daily dosing in healthy adults. A SMEDS enhances delivery of bioactive ω-3 fatty acids. This trial was registered at www.isrctn.com as ISRCTN96459690.


Asunto(s)
Ácidos Docosahexaenoicos/administración & dosificación , Sistemas de Liberación de Medicamentos , Ácido Eicosapentaenoico/administración & dosificación , Adulto , Ácidos Docosahexaenoicos/química , Método Doble Ciego , Esquema de Medicación , Quimioterapia Combinada , Ácido Eicosapentaenoico/química , Emulsiones/química , Femenino , Humanos , Masculino , Persona de Mediana Edad
2.
Lipids Health Dis ; 16(1): 204, 2017 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-29037249

RESUMEN

BACKGROUND: Absorption of EPA and DHA from Omega-3-acid ethyl ester (EE) concentrate supplements occurs most efficiently when taken in context of a fatty meal; adequate fat intake is required to release bile salts that emulsify and pancreatic enzymes that digest omega-3-containing lipids in the intestine. Current guidelines recommend reduction in fat intake and therefore there is a need to optimize the absorption of Omega-3 in those consuming low-fat or no-fat meals. To this end, BASF has developed an Absorption Acceleration Technology, a novel self-micro-emulsifying delivery system (SMEDS) formulation of highly concentrated Omega-3-acid EE which enables rapid emulsification and microdroplet formation upon entering the aqueous environment of the gut therefore enhances the absorption. METHODS: Two separate single dose, crossover studies were conducted to determine the relative bioavailability of omega-3-acid EE concentrate, either as a novel SMEDS formulation (PRF-021) or as control, in healthy fasted male and female adults at two dose levels (Study 1 "low dose": 630 mg EPA + DHA in PRF-021 vs. 840 mg EPA + DHA in control; Study 2 "high dose": 1680 mg EPA + DHA in PRF-021 vs. 3360 mg EPA + DHA in control). Blood samples were collected immediately before supplementation and at defined time intervals for 48 h. Plasma concentration of total EPA and DHA were determined for pharmacokinetic analysis, area under the curve (AUC) and maximum observed concentration (Cmax) was determined. RESULTS: Total EPA plus DHA absorption from SMEDS formulation PRF-021 were 6.4 and 11.5 times higher compared to control in low- and high-dose studies respectively, determined as the ratio of baseline corrected, dose normalized AUC0-24h of PRF-021 over that of control. EPA and DHA individually showed differing levels of enhancement: the AUC0-24h ratio for EPA was 23.8 and 25.7 in low and high dose studies, respectively, and the AUC0-24h ratio for DHA was 3.6 and 5.6 in low and high dose studies, respectively. Cmax was also increased for both EPA and DHA 2.7- to 9.2-fold. CONCLUSION: PRF-021 is a novel SMEDS formulation of Omega-3-acid EE demonstrating a marked improvement in absorption of a single dose of EPA and DHA EE under fasted conditions. This allows adequate absorption of Omega-3 from the supplement without the requirement of a high-fat meal.


Asunto(s)
Suplementos Dietéticos , Ácidos Docosahexaenoicos/farmacocinética , Sistemas de Liberación de Medicamentos/métodos , Ácido Eicosapentaenoico/farmacocinética , Absorción Intestinal/fisiología , Adulto , Área Bajo la Curva , Disponibilidad Biológica , Estudios Cruzados , Ácidos Docosahexaenoicos/administración & dosificación , Ácido Eicosapentaenoico/administración & dosificación , Emulsiones , Ésteres/administración & dosificación , Ayuno/fisiología , Femenino , Humanos , Masculino , Persona de Mediana Edad
3.
Cardiology ; 135(1): 3-12, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27160246

RESUMEN

OBJECTIVES: To evaluate the efficacy and safety of icosabutate, an oral, once-daily, first-in-class medication, in reducing non-high-density lipoprotein cholesterol (non-HDL-C) in patients with persistent hypertriglyceridemia despite statin therapy. METHODS: The study was designed to randomly assign 140 patients with fasting triglyceride levels ≥200 but <500 mg/dl on a stable dose of statin therapy to receive either masked icosabutate 600 mg once daily or a control for 12 weeks. The primary end point was a percentage change in non-HDL-C from baseline to 12 weeks. RESULTS: With icosabutate, non-HDL-C levels were reduced (-9.2%) when compared with the control (-0.4%) for a between-group difference of -7.4% (p = 0.02). Compared with the control, icosabutate reduced triglycerides (-27.0%, p < 0.001), very- low-density lipoprotein (VLDL) cholesterol (-31.5%, p < 0.001) and apolipoprotein C-III (-22.5%, p < 0.001). LDL-C levels did not change (0.5%, p = 0.87). HDL-C (10.2%, p < 0.001) was increased. After 113 subjects had been randomized, the study was terminated due to a partial clinical hold imposed by US regulators after observing QT prolongation at supratherapeutic doses of icosabutate in a dog study. In this study, adverse events were balanced between treatment arms, and there were no discontinuations due to adverse events. CONCLUSIONS: Icosabutate was efficacious in lowering non-HDL-C and other biomarkers of cardiovascular risk and was generally well tolerated.


Asunto(s)
Butiratos/uso terapéutico , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Hipertrigliceridemia/tratamiento farmacológico , Hipolipemiantes/uso terapéutico , Adulto , Anciano , Animales , Arritmias Cardíacas/inducido químicamente , Butiratos/efectos adversos , Enfermedades Cardiovasculares/prevención & control , Perros , Quimioterapia Combinada , Terminación Anticipada de los Ensayos Clínicos , Femenino , Humanos , Hipertrigliceridemia/sangre , Hipolipemiantes/efectos adversos , Lípidos/sangre , Masculino , Persona de Mediana Edad , Factores de Riesgo
4.
NMR Biomed ; 24(1): 96-103, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-20862657

RESUMEN

Analytical platforms for the fast detection, identification and quantification of circulating drugs with a narrow therapeutic range are vital in clinical pharmacology. As a result of low drug concentrations, analytical tools need to provide high sensitivity and specificity. Dynamic nuclear polarization-NMR (DNP-NMR) in the form of the hyperpolarization-dissolution method should afford the sensitivity and spectral resolution for the direct detection and quantification of numerous isotopically labeled circulating drugs and their metabolites in single liquid-state NMR transients. This study explores the capability of quantitative in vitro DNP-NMR to assay drug metabolites in blood plasma. The lower limit of detection for the anti-epileptic drug (13)C-carbamazepine and its pharmacologically active metabolite (13)C-carbamazepine-10,11-epoxide is 0.08 µg/mL in rabbit blood plasma analyzed by single-scan (13)C DNP-NMR. An internal standard is used for the accurate quantification of drug and metabolite. Comparison of quantitative DNP-NMR data with an established analytical method (liquid chromatography-mass spectrometry) yields a Pearson correlation coefficient r of 0.99. Notably, all DNP-NMR determinations were performed without analyte derivatization or sample purification other than plasma protein precipitation. Quantitative DNP-NMR is an emerging methodology which requires little sample preparation and yields quantitative data with high sensitivity for therapeutic drug monitoring.


Asunto(s)
Bioensayo/métodos , Carbamazepina/metabolismo , Espectroscopía de Resonancia Magnética/métodos , Plasma/metabolismo , Animales , Calibración , Carbamazepina/química , Carbamazepina/farmacocinética , Cromatografía Liquida , Interacciones Farmacológicas , Espectrometría de Masas , Conejos , Estándares de Referencia
5.
Am J Clin Nutr ; 114(3): 914-924, 2021 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-34113957

RESUMEN

BACKGROUND: Evidence regarding the effects of the omega-3 (É·-3) PUFAs (n-3 PUFAs) DHA and EPA on cognition is lacking. OBJECTIVES: We investigated whether supplementation with oils rich in EPA or DHA improves cognition, prefrontal cortex (PFC) hemoglobin (Hb) oxygenation, and memory consolidation. METHODS: Healthy adults (n = 310; age range: 25-49 y) completed a 26-wk randomized controlled trial in which they consumed either 900 mg DHA/d and 270 mg EPA/d (DHA-rich oil), 360 mg DHA/d and 900 mg EPA/d (EPA-rich oil), or 3000 mg/d refined olive oil (placebo). Cognitive performance and memory consolidation were assessed via computerized cognitive test battery. PFC Hb oxygenation was measured using near infrared spectroscopy (NIRS). RESULTS: Both global accuracy and speed improved with EPA-rich oil compared with placebo and DHA-rich oil [EPA vs. placebo accuracy: estimated marginal mean (EMM) = 0.17 (95% CI: 0.09, 0.24) vs. EMM = 0.03 (95% CI = -0.04, 0.11); P = 0.044; EPA vs. placebo speed: EMM = -0.15 (95% CI: -0.22, -0.07) vs. EMM = 0.03 (95% CI: -0.05, 0.10); P = 0.003]. Accuracy of memory was improved with EPA compared with DHA [EMM = 0.66 (95% CI: 0.26, 1.06) vs. EMM = -0.08 (95% CI: -0.49, 0.33); P = 0.034]. Both EPA- and DHA-rich oils showed trends towards reduced PFC oxygenated Hb (oxy-Hb) compared with placebo [placebo: EMM = 27.36 µM (95% CI: 25.73, 28.98); DHA: EMM = 24.62 µM (95% CI: 22.75, 26.48); P = 0.060; EPA: EMM = 24.97 µM (95% CI: 23.35, 26.59); P = 0.082]. CONCLUSIONS: EPA supplementation improved global cognitive function and was superior to the oil enriched with DHA. Interpreted within a neural efficiency framework, reduced PFC oxygenated Hb suggests that n-3 PUFAs may be associated with increased efficiency.These trials were registered in the clinical trials registry (https://clinicaltrials.gov/) as NCT03158545, NCT03592251, NCT02763514.


Asunto(s)
Cognición/efectos de los fármacos , Grasas Insaturadas en la Dieta/análisis , Suplementos Dietéticos , Ácidos Docosahexaenoicos/administración & dosificación , Ácidos Docosahexaenoicos/farmacología , Ácido Eicosapentaenoico/administración & dosificación , Ácido Eicosapentaenoico/farmacología , Adulto , Ácidos Docosahexaenoicos/química , Método Doble Ciego , Ácido Eicosapentaenoico/química , Femenino , Humanos , Masculino , Persona de Mediana Edad
6.
Nutrients ; 13(1)2021 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-33467135

RESUMEN

Emerging evidence suggests that adequate intake of omega-3 polyunsaturated fatty acids (n-3 PUFAs), which include docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), might be associated with better sleep quality. N-3 PUFAs, which must be acquired from dietary sources, are typically consumed at suboptimal levels in Western diets. Therefore, the current placebo-controlled, double-blind, randomized trial, investigated the effects of an oil rich in either DHA or EPA on sleep quality in healthy adults who habitually consumed low amounts of oily fish. Eighty-four participants aged 25-49 years completed the 26-week intervention trial. Compared to placebo, improvements in actigraphy sleep efficiency (p = 0.030) and latency (p = 0.026) were observed following the DHA-rich oil. However, these participants also reported feeling less energetic compared to the placebo (p = 0.041), and less rested (p = 0.017), and there was a trend towards feeling less ready to perform (p = 0.075) than those given EPA-rich oil. A trend towards improved sleep efficiency was identified in the EPA-rich group compared to placebo (p = 0.087), along with a significant decrease in both total time in bed (p = 0.032) and total sleep time (p = 0.019) compared to the DHA-rich oil. No significant effects of either treatment were identified for urinary excretion of the major melatonin metabolite 6-sulfatoxymelatonin. This study was the first to demonstrate some positive effects of dietary supplementation with n-3 PUFAs in healthy adult normal sleepers, and provides novel evidence showing the differential effects of n-3 PUFA supplements rich in either DHA or EPA. Further investigation into the mechanisms underpinning these observations including the effects of n-3 PUFAs on sleep architecture are required.


Asunto(s)
Grasas Insaturadas en la Dieta/administración & dosificación , Suplementos Dietéticos , Ácidos Docosahexaenoicos/administración & dosificación , Ácidos Docosahexaenoicos/farmacología , Ingestión de Alimentos/fisiología , Ácido Eicosapentaenoico/administración & dosificación , Ácido Eicosapentaenoico/farmacología , Voluntarios Sanos/psicología , Sueño/efectos de los fármacos , Sueño/fisiología , Adulto , Dieta Occidental , Método Doble Ciego , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores de Tiempo
7.
Artículo en Inglés | MEDLINE | ID: mdl-32018166

RESUMEN

Knowledge of the diurnal variation in circulating omega-3 polyunsaturated fatty acids (n-3 PUFAs) may be an important consideration for the development of dosing protocols designed to optimise tissue delivery of these fatty acids. The objective of the current study was to examine the variation in plasma concentrations of eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) over a 24-h period in healthy adults under eating and sleeping conditions generally approximate to a free-living environment. Twenty-one healthy participants aged 25-44 years took part in a single laboratory visit encompassing an overnight stay. EPA and DHA were measured in plasma samples collected every two hours from 22:00 until 22:00 the following day, with all meals being provided at conventional times. Cosinor analysis was used to estimate the diurnal variation in each fatty acid from pooled data across all participants. A significant diurnal variation in the pooled plasma concentrations of both fatty acids was detected. However, evidence of distinct rhythmicity was strongest for DHA. The timing of the peak concentration of DHA was 17:43 with a corresponding nadir at 05:43. In comparison, the observed acrophase for EPA was delayed by three hours, occurring at 20:41, with a nadir at 08:41. This is the first time that the diurnal variation in these important bioactive fatty acids has been described in a sample of healthy adults following a normal pattern of eating and sleeping. In the absence of any dietary intake of EPA and DHA, circulating levels of these fatty acids fall during the overnight period and reach their lowest point in the morning. Consumption of n-3 PUFAs at night time, which counteracts this pattern, may have functional significance.


Asunto(s)
Ritmo Circadiano , Ácidos Docosahexaenoicos/sangre , Ácido Eicosapentaenoico/análogos & derivados , Adulto , Ácidos Docosahexaenoicos/administración & dosificación , Ingestión de Alimentos , Ácido Eicosapentaenoico/administración & dosificación , Ácido Eicosapentaenoico/sangre , Femenino , Humanos , Masculino , Sueño
8.
Invest Radiol ; 41(7): 560-71, 2006 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16772849

RESUMEN

OBJECTIVES: We sought to evaluate the effect of the particle size and coating material of various iron oxide preparations on the rate of rat liver clearance. MATERIALS AND METHODS: The following iron oxide formulations were used in this study: dextran-coated ferumoxide (size = 97 nm) and ferumoxtran-10 (size = 21 nm), carboxydextran-coated SHU555A (size = 69 nm) and fractionated SHU555A (size = 12 nm), and oxidized-starch coated materials either unformulated NC100150 (size = 15 nm) or formulated NC100150 injection (size = 12 nm). All formulations were administered to 165 rats at 2 dose levels. Quantitative liver R2* values were obtained during a 63-day time period. The concentration of iron oxide particles in the liver was determined by relaxometry, and these values were used to calculate the particle half-lives in the liver. RESULTS: After the administration of a high dose of iron oxide, the half-life of iron oxide particles in rat liver was 8 days for dextran-coated materials, 10 days for carboxydextran materials, 14 days for unformulated oxidized-starch, and 29 days for formulated oxidized-starch. CONCLUSIONS: The results of the study indicate that materials with similar coating but different sizes exhibited similar rates of liver clearance. It was, therefore, concluded that the coating material significantly influences the rate of iron oxide clearance in rat liver.


Asunto(s)
Medios de Contraste/farmacocinética , Hierro/farmacocinética , Hígado/metabolismo , Imagen por Resonancia Magnética , Óxidos/farmacocinética , Animales , Dextranos , Óxido Ferrosoférrico , Nanopartículas de Magnetita , Masculino , Tamaño de la Partícula , Ratas , Ratas Sprague-Dawley , Propiedades de Superficie
9.
Ultrasound Med Biol ; 32(1): 107-14, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16364802

RESUMEN

The new ultrasound contrast agent Sonazoid was injected IV in rats at doses of 0.8 and 8 muL perfluorobutane (PFB)-containing microbubbles/kg body weight. Samples were obtained from blood, liver, spleen, fat, kidney, muscle, heart, lung and brain from both males and females and the PFB gas was analyzed using validated gas chromatography mass spectrometry methods. No differences were observed between genders or doses for any of the pharmacokinetic parameters. For all tissues, the highest concentrations were observed at the first time point (i.e., 5 min postinjection) (51% of injected dose in liver; total recovery of 69%). The highest concentrations of PFB in tissue were observed in spleen > liver > lung > kidney >> other tissues. At 24 h after dosing, the total amount of PFB remaining in the tissues was 1.9%. These data fit well with the finding that after a Sonazoid dose of 8 microL microbubbles/kg to male rats, more than 50% of the injected PFB was recovered in exhaled air by 20 min after dosing. During the first 24 h after administration, more than 96% of the PFB dose was recovered in exhaled air.


Asunto(s)
Medios de Contraste/administración & dosificación , Compuestos Férricos/administración & dosificación , Fluorocarburos/farmacocinética , Hierro/administración & dosificación , Óxidos/administración & dosificación , Animales , Pruebas Respiratorias , Relación Dosis-Respuesta a Droga , Femenino , Fluorocarburos/análisis , Inyecciones Intravenosas , Masculino , Microburbujas , Ratas , Ratas Sprague-Dawley , Distribución Tisular
10.
Pharmacol Res Perspect ; 4(6): e00274, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-28097007

RESUMEN

Acoustic Cluster Therapy (ACT) represents a novel concept for targeted drug delivery. Ultrasound is applied to activate intravenously administered free-flowing clusters of microbubbles and microdroplets within the target pathology, depositing 20-30 µm large bubbles in the microvasculature for 5-10 min. Further application of ultrasound induces biomechanical effects which increase vascular permeability and enhance localized extravasation of coadministered drugs. Herein we report investigations done to assess the preclinical safety of ACT, using doses up to 1 mL/kg (3 µL perfluoromethyl-cyclopentane/kg). In dogs, half the animals were exposed to ultrasound activation in the heart for 1 min, no ultrasound was applied in the other half. Posttreatment observation time was 24 h. Clinical signs, ophthalmoscopy, clinical pathology, macro-, and microscopy were used as endpoints. No differences between groups with and without ultrasound activation were observed. Short-lasting leukopenia and thrombocytopenia, possibly secondary to a slight and short-lasting increase in plasma histamine and complement split products, were the only effects noted. In rats ACT was activated in the liver for 5 min. Histopathology and clinical chemistry parameters remained unchanged. Lastly, rats were treated with ACT activated in the heart and thereafter placed on a rotarod for evaluation of motor coordination. No differences were observed between animals treated with ACT and controls. In conclusion, ACT appeared safe at dose-levels up to 1 mL/kg and with activation either in the heart or the liver. These results, together with positive efficacy data upon coinjection with cytotoxic compounds encourage further preclinical safety studies with the objective of entering subsequent clinical trials.

11.
J Clin Lipidol ; 10(1): 181-91.e1-2, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26892135

RESUMEN

BACKGROUND: Icosabutate is a structurally enhanced omega-3 fatty acid molecule developed with the aim of achieving improved triglyceride (TG)-lowering efficacy, increased potency, and preserved safety compared with conventional prescription omega-3 fatty acid. OBJECTIVE: To evaluate the efficacy and safety of icosabutate 600 mg once daily in patients with very high TGs. METHODS: After a 6-8 week run-in period, men and women with TG levels ≥ 500 mg/dL and ≤ 1500 mg/dL were randomized to double-blind treatment with placebo or icosabutate 600 mg for 12 weeks. The primary end point was % change from baseline in TGs at 12 weeks. RESULTS: A total of 87 subjects were randomized. At baseline, median TG (interquartile range) levels were 611 (543-878) and 688 (596-892) mg/dL, and the median change after 12 weeks of treatment was -51% and -17%, respectively, for a placebo-corrected change of -33% (P < .001). Adjusted for placebo, icosabutate significantly reduced very low-density lipoprotein cholesterol (-36%, P < .001), remnant lipoprotein cholesterol (-34%, P < .001), apolipoprotein (Apo) C-III (-35%, P < .001), trended toward reduced non-high-density lipoprotein cholesterol (-7%, P = .064); significantly increased high-density lipoprotein cholesterol (18%, P < .001) and low-density lipoprotein cholesterol (28%, P < .001), with a trend of an increased lipoprotein (a; 10%, P = .054). No changes were observed in total cholesterol, apolipoprotein B, or apolipoprotein A1. Fasting plasma glucose was unchanged, whereas fasting plasma insulin was reduced (P = .001) with icosabutate. Icosabutate was generally well tolerated. CONCLUSION: Treatment with icosabutate once daily significantly reduced TG, very low-density lipoprotein cholesterol, and Apo C-III levels in patients with very high TG levels. This trial was registered at www.clinicaltrials.gov as NCT01893515.


Asunto(s)
Ácidos Grasos Omega-3/uso terapéutico , Hipolipemiantes/uso terapéutico , Triglicéridos/sangre , Adolescente , Adulto , Anciano , Método Doble Ciego , Ácidos Grasos Omega-3/química , Ácidos Grasos Omega-3/farmacología , Femenino , Humanos , Hipertrigliceridemia/sangre , Hipertrigliceridemia/tratamiento farmacológico , Hipolipemiantes/química , Hipolipemiantes/farmacología , Masculino , Persona de Mediana Edad , Placebos , Adulto Joven
12.
Contrast Media Mol Imaging ; 4(2): 73-80, 2009.
Artículo en Inglés | MEDLINE | ID: mdl-19142979

RESUMEN

The present study demonstrates the usefulness of whole body section fluorescence imaging, a novel technique used in optical imaging drug discovery. This method is in principle an analog of whole body autoradiography, except that fluorescence is measured instead of radioactivity. The method was shown to have a linear concentration-response relationship over a 1000-fold concentration range. Densitometric image analysis allowed semiquantitative studies of drug disposition and selective tumor retention of an optical imaging drug candidate.


Asunto(s)
Autorradiografía/métodos , Diagnóstico por Imagen/métodos , Fluorescencia , Recuento Corporal Total/métodos , Animales , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Distribución Tisular
13.
Drug Metab Dispos ; 34(1): 111-20, 2006 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-16251253

RESUMEN

The 99mTc-complex of NC100668 [Acetyl-Asn-Gln-Glu-Gln-Val-Ser-Pro-Tyr(3-iodo)-Thr-Leu-Leu-Lys-Gly-NC100194] is being evaluated for nuclear medical imaging of venous thromboembolism. NC100668 is a 13-amino acid peptide with a Tc-binding chelator [NC100194; -NH-CH2-CH2-N(CH2-CH2-NH-C(CH3)2-C(CH3)=N-OH)2] linked to the C-terminal end. Following injection in rats of [Asn-U-14C]NC100668 (labeling of the N-terminal amino acid), approximately 70% of the radioactivity was recovered in urine within 3 days. Following injection of [Lys-U-14C]NC100668 (labeling close to the C-terminal amino acid), radioactivity was cleared more slowly, with only 8% recovered in urine and approximately 80% of the radioactivity present in the body after 3 days. The highest concentration of radioactivity in the body following injection of [Lys-U-14C]NC100668 was observed in the kidney inner cortex; this probably represents 14C-labeled Lys, which is reabsorbed in the kidney tubules and incorporated into protein metabolism. Metabolite profiling by high-performance liquid chromatography with radiochemical detection revealed that following injection of [Asn-U-14C]NC100668, there is a rapid appearance in blood of one peak containing radioactive metabolite(s) originating from the N-terminal part of the molecule. In urine samples, only this radioactive peak was observed with no intact NC100668 remaining; this very hydrophilic N-terminal metabolite was probably either the N-terminal amino acid or a very short peptide. Liquid chromatography-mass spectrometry analyses of rat urine samples obtained after injection of nonlabeled NC100668 confirmed the identity of two metabolites generated from the C-terminal end of the molecule; Gly-NC100194 was identified as the major of these metabolites and NC100194 as a minor metabolite present at approximately one-tenth the amount of Gly-NC100194. No other metabolites were identified.


Asunto(s)
Péptidos/metabolismo , Péptidos/farmacocinética , Trazadores Radiactivos , Radiofármacos/metabolismo , Radiofármacos/farmacocinética , Secuencia de Aminoácidos , Animales , Animales no Consanguíneos , Autorradiografía , Cromatografía Líquida de Alta Presión/métodos , Estabilidad de Medicamentos , Heces/química , Femenino , Cromatografía de Gases y Espectrometría de Masas/métodos , Aumento de la Imagen/métodos , Inyecciones , Péptidos y Proteínas de Señalización Intercelular , Masculino , Fragmentos de Péptidos/metabolismo , Fragmentos de Péptidos/orina , Péptidos/síntesis química , Unión Proteica/efectos de los fármacos , Cintigrafía , Radiofármacos/síntesis química , Ratas , Tromboembolia/diagnóstico , Tromboembolia/diagnóstico por imagen , Distribución Tisular , Trombosis de la Vena/diagnóstico , Trombosis de la Vena/diagnóstico por imagen
14.
J Magn Reson Imaging ; 20(4): 622-31, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15390223

RESUMEN

PURPOSE: To investigate the duration of liver R2* enhancement and pharmacokinetics following administration of an iron oxide nanoparticle in a rat model. MATERIALS AND METHODS: Rats were injected with 0, 1, 2, or 5 mg Fe/kg of NC100150 Injection, and quantitative in vivo 1/T2* liver measurements were obtained between 1 and 133 days after injection. The concentration of NC100150 Injection was determined by relaxometry methods in ex vivo rat liver homogenate. RESULTS: At all dose levels, 1/T2* remained greater than control values up to 63 days after injection. In the highest dose group, 1/T2* was above control levels during the entire 133 day time-course investigated. There were no quantifiable amounts of NC100150 Injection present 63 days after injection in any of the dose groups. The half-life of NC100150 Injection in rat liver was dose dependent. For the lowest dose group, the degradation of the particles could be defined by a mono-exponential function with a half-life of eight days. For the 2 and 5 mg Fe/kg dose groups, the degradation was bi-exponential with a fast initial decay of seven to eight days followed by a slow terminal decay of 43-46 days. CONCLUSION: NC100150 Injection exhibits prolonged 1/T2* enhancement in rat liver. The liver enhancement persisted at time points when the concentration of iron oxide particles present in the liver was below method detection limits. The prolonged 1/T2* enhancement is likely a result of the particle breakdown products and the induction of ferritin and hemosiderin with increasing iron cores/loading factors.


Asunto(s)
Medios de Contraste/farmacocinética , Hierro/farmacocinética , Hígado/metabolismo , Imagen por Resonancia Magnética/métodos , Óxidos/farmacocinética , Análisis de Varianza , Animales , Medios de Contraste/administración & dosificación , Dextranos , Óxido Ferrosoférrico , Hierro/administración & dosificación , Nanopartículas de Magnetita , Masculino , Óxidos/administración & dosificación , Ratas
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