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Introduction: Graft survival in pediatric kidney transplant patients has increased significantly within the last three decades, correlating with the discovery and utilization of new immunosuppressants as well as improvements in patient care. Despite these developments in graft survival for patients, there is still improvement needed, particularly in long-term care in pediatric patients receiving grafts from deceased donor patients. Maintenance immunosuppressive therapies have narrow therapeutic indices and are associated with high inter-individual and intra-individual variability.Areas covered: In this review, we examine the impact of pharmacokinetic variability on renal transplantation and its association with age, genetic polymorphisms, drug-drug interactions, drug-disease interactions, renal insufficiency, route of administration, and branded versus generic drug formulation. Pharmacodynamics are outlined in terms of the mechanism of action for each immunosuppressant, potential adverse effects, and the utility of pharmacodynamic biomarkers.Expert opinion: Acquiring abetter quantitative understanding of immunosuppressant pharmacokinetics and pharmacodynamic components should help clinicians implement treatment regimens to maintain the balance between therapeutic efficacy and drug-related toxicity.
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Supervivencia de Injerto/efectos de los fármacos , Inmunosupresores/administración & dosificación , Trasplante de Riñón/métodos , Factores de Edad , Niño , Interacciones Farmacológicas , Humanos , Inmunosupresores/efectos adversos , Inmunosupresores/farmacocinética , Polimorfismo GenéticoRESUMEN
Supplemental arginine has shown promise as a safe therapeutic option to improve endogenous nitric oxide (NO) regulation in cardiovascular diseases associated with endothelial dysfunction. In clinical studies in adults, L-arginine, an endogenous amino acid, was reported to improve cardiovascular function in hypertension, pulmonary hypertension, preeclampsia, angina, and MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) syndrome. L-citrulline, a natural precursor of L-arginine, is more bioavailable than L-arginine because it avoids hepatic first-pass metabolism and has a longer circulation time. Although not yet well-studied, arginine/citrulline has immense therapeutic potential in some life-threatening diseases in children. However, the optimal clinical development of arginine or citrulline in children requires more information about pharmacokinetics and exposure-response relationships at appropriate ages and under relevant disease states. This article summarizes the preclinical and clinical studies of arginine/citrulline in both adults and children, including currently available pharmacokinetic information. The pharmacology of arginine/citrulline is confounded by several patient-specific factors such as variations in baseline arginine/citrulline due to developmental ages and disease states. Currently available pharmacokinetic studies are insufficient to inform the optimal design of clinical studies, especially in children. Successful bench-to-bedside clinical translation of arginine supplementation awaits information from well-designed pharmacokinetic/pharmacodynamic studies, along with pharmacometric approaches.
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Arginina/uso terapéutico , Citrulina/uso terapéutico , Farmacología Clínica/métodos , Adolescente , Adulto , Arginina/farmacología , Niño , Citrulina/farmacología , Femenino , Humanos , Masculino , Adulto JovenRESUMEN
Physiologically based pharmacokinetic modeling and simulation is an important tool for predicting the pharmacokinetics, pharmacodynamics, and safety of drugs in pediatrics. Physiologically based pharmacokinetic modeling is applied in pediatric drug development for first-time-in-pediatric dose selection, simulation-based trial design, correlation with target organ toxicities, risk assessment by investigating possible drug-drug interactions, real-time assessment of pharmacokinetic-safety relationships, and assessment of non-systemic biodistribution targets. This review summarizes the details of a physiologically based pharmacokinetic modeling approach in pediatric drug research, emphasizing reports on pediatric physiologically based pharmacokinetic models of individual drugs. We also compare and contrast the strategies employed by various researchers in pediatric physiologically based pharmacokinetic modeling and provide a comprehensive overview of physiologically based pharmacokinetic modeling strategies and approaches in pediatrics. We discuss the impact of physiologically based pharmacokinetic models on regulatory reviews and product labels in the field of pediatric pharmacotherapy. Additionally, we examine in detail the current limitations and future directions of physiologically based pharmacokinetic modeling in pediatrics with regard to the ability to predict plasma concentrations and pharmacokinetic parameters. Despite the skepticism and concern in the pediatric community about the reliability of physiologically based pharmacokinetic models, there is substantial evidence that pediatric physiologically based pharmacokinetic models have been used successfully to predict differences in pharmacokinetics between adults and children for several drugs. It is obvious that the use of physiologically based pharmacokinetic modeling to support various stages of pediatric drug development is highly attractive and will rapidly increase, provided the robustness and reliability of these techniques are well established.
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Desarrollo de Medicamentos , Modelos Biológicos , Farmacocinética , Niño , Desarrollo de Medicamentos/legislación & jurisprudencia , Humanos , Legislación de MedicamentosRESUMEN
Currently, dual- or triple-drug combinations comprising different vasodilators are the mainstay for the treatment of pulmonary arterial hypertension (PAH). However, the patient outcome continues to be disappointing because the existing combination therapy cannot restrain progression of the disease. Previously, we have shown that when given as a monotherapy, long-acting inhaled formulations of sildenafil (a phosphodiesterase-5 inhibitor) and rosiglitazone (a peroxisome proliferator receptor-γ agonist) ameliorate PAH in rats. Thus, with a goal to develop a new combination therapy, we prepared and characterized poly(lactic-co-glycolic acid) (PLGA)-based long-acting inhalable particles of sildenafil and rosiglitazone. We then assessed the efficacy of the combinations of sildenafil and rosiglitazone, given in plain forms or as PLGA particles, in reducing mean pulmonary arterial pressure (mPAP) and improving pulmonary arterial remodeling and right ventricular hypertrophy (RVH) in Sugen 5416 plus hypoxia-induced PAH rats. After intratracheal administration of the formulations, we catheterized the rats and measured mPAP, cardiac output, total pulmonary resistance, and RVH. We also conducted morphometric studies using lung tissue samples and assessed the degree of muscularization, the arterial medial wall thickening, and the extent of collagen deposition. Compared with the plain drugs, given via the pulmonary or oral route as a single or dual combination, PLGA particles of the drugs, although given at a longer dosing interval compared with the plain drugs, caused more pronounced reduction in mPAP without affecting mean systemic pressure, improved cardiac function, slowed down right heart remodeling, and reduced arterial muscularization. Overall, PLGA particles of sildenafil and rosiglitazone, given as an inhaled combination, could be a viable alternative to currently available vasodilator-based combination therapy for PAH.
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Hemodinámica/efectos de los fármacos , Hipertensión Pulmonar , Rosiglitazona/farmacología , Citrato de Sildenafil/farmacología , Remodelación Vascular/efectos de los fármacos , Administración por Inhalación , Animales , Quimioterapia Combinada , Pruebas de Función Cardíaca , Hipertensión Pulmonar/tratamiento farmacológico , Hipertensión Pulmonar/patología , Hipertensión Pulmonar/fisiopatología , Hipertrofia Ventricular Derecha/tratamiento farmacológico , Hipertrofia Ventricular Derecha/patología , Hipertrofia Ventricular Derecha/fisiopatología , Masculino , Arteria Pulmonar/patología , Arteria Pulmonar/fisiopatología , Ratas , Ratas Sprague-DawleyRESUMEN
The prevalence of pulmonary methicillin-resistant Staphylococcus aureus infections in patients with cystic fibrosis (CF) has increased over the last 2 decades. Two concentrations-a postdistributive and a trough-are currently used to estimate the area under the curve (AUC) of vancomycin, an antibiotic routinely used to treat these infections, to achieve the target AUC/minimum inhibitory concentration of ≥400 mg·h/L in ensuring optimal dosing of this drug. This study evaluated precision and bias in estimating vancomycin AUCs obtained either from a population pharmacokinetic (PK) model by using a single trough concentration or from standard PK equation-based 2-point monitoring approach. AUCs were either obtained from a single trough concentration-fitted model or derived from a model fitted by 2 concentration points. Children ≥2 years of age with CF received intravenous vancomycin at 2 centers from June 2012 to December 2014. A population PK model was developed in Pmetrics to quantify the between-subject variability in vancomycin PK parameters, define the sources of PK variability, and leverage information from the population to improve individual AUC estimates. Twenty-three children with CF received 27 courses of vancomycin. The median age was 12.3 (interquartile range [IQR] 8.5-16.6) years. From the individual vancomycin PK parameter estimates from the population PK model, median AUC was 622 (IQR 529-680) mg·h/L. Values were not significantly different from the AUC calculated using the standard PK equation-based approach (median 616 [IQR 540-663] mg·h/L) (P = .89). A standard PK equation-based approach using 2 concentrations and a population PK model-based approach using a single trough concentration yielded unbiased and precise AUC estimates. Findings suggest that options exist to implement AUC-based pediatric vancomycin dosing in patients with CF. The findings of this study reveal that several excellent options exist for centers to implement AUC-based pediatric vancomycin dosing for patients with CF.
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Área Bajo la Curva , Fibrosis Quística/tratamiento farmacológico , Staphylococcus aureus Resistente a Meticilina/efectos de los fármacos , Vancomicina/farmacocinética , Adolescente , Niño , Preescolar , Femenino , Humanos , Masculino , FarmacocinéticaRESUMEN
Peroxisome-proliferator-activated-receptor-gamma (PPAR-γ) is implicated, in some capacity, in the pathogenesis of pulmonary arterial hypertension (PAH). Rosiglitazone, an oral antidiabetic and PPAR-γ agonist, has the potential to dilate pulmonary arteries and to attenuate arterial remodeling in PAH. Here, we sought to test the hypothesis that rosiglitazone can be repurposed as inhaled formulation for the treatment of PAH. We have tested this conjecture by preparing and optimizing poly(lactic-co-glycolic) acid (PLGA) based particles of rosiglitazone, assessing the drug particles for pulmonary absorption, investigating the efficacy of the plain versus particulate drug formulation in improving the respiratory hemodynamics in PAH animals, and finally studying the effect of the drug in regulating the molecular markers associated with PAH pathogenesis. The optimized particles were slightly porous and spherical, and released 87.9%⯱â¯6.7% of the drug in 24â¯h. The elimination half-life of the drug formulated in PLGA particles was 2.5-fold greater than that of the plain drug administered via the same route at the same dose. The optimized formulation, given via the pulmonary route, produced pulmonary selective vasodilation in PAH animals, but oral rosiglitazone had no effect in pulmonary hemodynamics. Rosiglitazone ameliorates the pathogenesis of PAH by balancing the molecular regulators involved in the vasoconstriction and vasodilation of human pulmonary arterial smooth muscle cells. All in all, data generated using intact animal and cellular models point to the conclusion that PLGA particles of an antidiabetic drug can be used for the treatment of a different disease, PAH.
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Reposicionamiento de Medicamentos/métodos , Hipertensión Pulmonar Primaria Familiar/tratamiento farmacológico , Hipoglucemiantes/farmacología , PPAR gamma/agonistas , Rosiglitazona/farmacología , Administración por Inhalación , Animales , Portadores de Fármacos/química , Composición de Medicamentos/métodos , Liberación de Fármacos , Humanos , Hipoglucemiantes/administración & dosificación , Hipoglucemiantes/efectos adversos , Hipoglucemiantes/uso terapéutico , Masculino , Modelos Animales , Músculo Liso Vascular/efectos de los fármacos , Miocitos del Músculo Liso , Copolímero de Ácido Poliláctico-Ácido Poliglicólico/química , Porosidad , Arteria Pulmonar/efectos de los fármacos , Ratas Sprague-Dawley , Rosiglitazona/administración & dosificación , Rosiglitazona/efectos adversos , Rosiglitazona/uso terapéutico , Resultado del TratamientoRESUMEN
We investigated the feasibility of a combination therapy comprising fasudil, a Rho-kinase inhibitor, and DETA NONOate (diethylenetriamine NONOate, DN), a long-acting nitric oxide donor, both loaded in liposomes modified with a homing peptide, CAR (CARSKNKDC), in the treatment of pulmonary arterial hypertension (PAH). We first prepared and characterized unmodified and CAR-modified liposomes of fasudil and DN. Using individual drugs alone or a mixture of fasudil and DN as controls, we studied the efficacy of the two liposomal preparations in reducing mean pulmonary arterial pressure (mPAP) in monocrotaline (MCT) and SUGEN-hypoxia-induced PAH rats. We also conducted morphometric studies (degree of muscularization, arterial medial wall thickness, and collagen deposition) after treating the PAH rats with test and control formulations. When the rats were treated acutely and chronically, the reduction in mPAP was more pronounced in the liposomal formulation-treated rats than in plain drug-treated rats. CAR-modified liposomes were more selective in reducing mPAP than unmodified liposomes of the drugs. Both drugs, formulated in CAR-modified liposomes, reduced the degree of muscularization, medial arterial wall thickness, and collagen deposition more than the combination of plain drugs did. As seen with the in vivo data, CAR-modified liposomes of fasudil or DN increased the levels of the vasodilatory signaling molecule, cGMP, in the smooth muscle cells of PAH-afflicted human pulmonary arteries. Overall, fasudil and DN, formulated in liposomes, could be used as a combination therapy for a better management of PAH.
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1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/análogos & derivados , Hipertensión Pulmonar/tratamiento farmacológico , Liposomas/química , Pulmón/efectos de los fármacos , Donantes de Óxido Nítrico/farmacología , Péptidos/farmacología , Poliaminas/farmacología , Arteria Pulmonar/efectos de los fármacos , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/farmacología , Animales , Química Farmacéutica/métodos , Progresión de la Enfermedad , Hipertensión Pulmonar/metabolismo , Pulmón/metabolismo , Masculino , Monocrotalina/farmacología , Miocitos del Músculo Liso/efectos de los fármacos , Miocitos del Músculo Liso/metabolismo , Arteria Pulmonar/metabolismo , Ratas , Ratas Sprague-Dawley , Vasodilatadores/farmacología , Quinasas Asociadas a rho/metabolismoRESUMEN
The practice of treating PAH patients with oral or intravenous sildenafil suffers from the limitations of short dosing intervals, peripheral vasodilation, unwanted side effects, and restricted use in pediatric patients. In this study, we sought to test the hypothesis that inhalable poly(lactic-co-glycolic acid) (PLGA) particles of sildenafil prolong the release of the drug, produce pulmonary specific vasodilation, reduce the systemic exposure of the drug, and may be used as an alternative to oral sildenafil in the treatment of PAH. Thus, we prepared porous PLGA particles of sildenafil using a water-in-oil-in-water double emulsion solvent evaporation method with polyethyleneimine (PEI) as a porosigen and characterized the formulations for surface morphology, respirability, in-vitro drug release, and evaluated for in vivo absorption, alveolar macrophage uptake, and safety. PEI increased the particle porosity, drug entrapment, and produced drug release for 36h. Fluorescent particles showed reduced uptake by alveolar macrophages. The polymeric particles were safe to rat pulmonary arterial smooth muscle cell and to the lungs, as evidenced by the cytotoxicity assay and analyses of the injury markers in the bronchoalveolar lavage fluid, respectively. Intratracheally administered sildenafil particles elicited more pulmonary specific and sustained vasodilation in SUGEN-5416/hypoxia-induced PAH rats than oral, intravenous, or intratracheal plain sildenafil did, when administered at the same dose. Overall, true to the hypothesis, this study shows that inhaled PLGA particles of sildenafil can be administered, as a substitute for oral form of sildenafil, at a reduced dose and longer dosing interval.
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Hipertensión Pulmonar/tratamiento farmacológico , Inhibidores de Fosfodiesterasa 5/administración & dosificación , Citrato de Sildenafil/administración & dosificación , Vasodilatadores/administración & dosificación , Administración por Inhalación , Administración Oral , Animales , Portadores de Fármacos , Humanos , Hipertensión Pulmonar/patología , Ácido Láctico/química , Macrófagos Alveolares/metabolismo , Masculino , Microesferas , Músculo Liso Vascular/efectos de los fármacos , Músculo Liso Vascular/patología , Tamaño de la Partícula , Inhibidores de Fosfodiesterasa 5/farmacocinética , Polietileneimina/química , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Porosidad , Arteria Pulmonar/efectos de los fármacos , Arteria Pulmonar/patología , Ratas Sprague-Dawley , Citrato de Sildenafil/farmacocinética , Propiedades de Superficie , Vasodilatadores/farmacocinéticaRESUMEN
Currently, two or more pulmonary vasodilators are used to treat pulmonary arterial hypertension (PAH), but conventional vasodilators alone cannot reverse disease progression. In this study, we tested the hypothesis that a combination therapy comprising a vasodilator plus a therapeutic agent that slows pulmonary arterial remodeling and right heart hypertrophy is an efficacious alternative to current vasodilator-based PAH therapy. Thus, we encapsulated a cocktail of superoxide dismutase (SOD), a superoxide scavenger, and fasudil, a specific rho-kinase inhibitor, into a liposomal formulation equipped with a homing peptide, CAR. We evaluated the effect of the formulations on pulmonary hemodynamics in monocrotaline-induced PAH rats (MCT-induced PAH) and assessed the formulation's efficacy in slowing the disease progression in Sugen-5416/hypoxia-induced PAH rats (SU/hypoxia-induced PAH). For acute studies, we monitored both mean pulmonary and systemic arterial pressures (mPAP and mSAP) for 2 to 6 h after a single dose of the plain drugs or formulations. In chronic studies, PAH rats received plain drugs every 48 h and the formulations every 72 h for 21 days. In MCT-induced PAH rats, CAR-modified liposomes containing fasudil plus SOD elicited a more pronounced, prolonged, and selective reduction in mPAP than unmodified liposomes and plain drugs did. In SU/hypoxia-induced PAH rats, the formulation produced a >50% reduction in mPAP and slowed right ventricular hypertrophy. When compared with individual plain drugs or combination, CAR-modified-liposomes containing both drugs reduced the extent of collagen deposition, muscularization of arteries, increased SOD levels in the lungs, and decreased the expression of pSTAT-3 and p-MYPT1. Overall, CAR-modified-liposomes of SOD plus fasudil, given every 72 h, was as efficacious as plain drugs, given every 48 h, suggesting that the formulation can reduce the total drug intake, systemic exposures, and dosing frequency.
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1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/análogos & derivados , Hipertensión Pulmonar/tratamiento farmacológico , Liposomas/farmacología , Superóxido Dismutasa/farmacología , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/farmacología , Animales , Presión Arterial/efectos de los fármacos , Química Farmacéutica/métodos , Hemodinámica/efectos de los fármacos , Hipertensión Pulmonar/metabolismo , Hipertrofia Ventricular Derecha/tratamiento farmacológico , Hipertrofia Ventricular Derecha/metabolismo , Pulmón/efectos de los fármacos , Pulmón/metabolismo , Masculino , Monocrotalina/farmacología , Ratas , Ratas Sprague-Dawley , Vasodilatadores , Quinasas Asociadas a rho/metabolismoRESUMEN
Montelukast, a cysteinyl leukotriene type 1 receptor antagonist, exhibits secondary anti-inflammatory properties when used at higher concentrations. Low-molecular-weight heparin (LMWH) evokes pronounced anti-inflammatory effects by interrupting leukocyte adhesion and migration. We hypothesized that inhalable particles containing montelukast plus LMWH release both drugs in a sustained fashion and protect the lungs against allergen-induced inflammation. Large porous particles of montelukast and LMWH were prepared using a double-emulsion-solvent-evaporation method. Montelukast was first encapsulated in copolymer-based particles using polyethylenimine as a porosigen; the resulting particles were then coated with LMWH. The particles were evaluated for physicochemical properties, respirability, and release profiles. The anti-inflammatory effect of the optimized formulation was studied in ovalbumin-sensitized asthmatic Sprague Dawley rats. The optimized large porous particles had a diameter of 10.3 ± 0.7 µm, exhibited numerous surface indentations and pores, showed acceptable drug entrapment efficiency (66.8% ± 0.4% for montelukast; 91.7% ± 0.8% adsorption efficiency for LMWH), demonstrated biphasic release patterns, and escaped the uptake by the rat alveolar macrophages. The number of infiltrating inflammatory cells in asthmatic rat lungs, treated with dual-drug particles, was >74% fewer than in untreated asthmatic rat lungs. Similarly, the airway walls of asthmatic animals treated with dual-drug particles were 3-fold thinner than those of untreated asthmatic animals (p < 0.001). The optimized formulation protects lungs against methacholine-induced airway hyper-reactivity. Overall, this study demonstrates the feasibility of loading 2 drugs, montelukast and LMWH, into an inhalable particulate system and establishes that this novel combination therapy produces sustained drug release and elicits a robust anti-inflammatory response in the lungs.
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Acetatos/administración & dosificación , Asma/tratamiento farmacológico , Sistemas de Liberación de Medicamentos/métodos , Heparina de Bajo-Peso-Molecular/administración & dosificación , Microesferas , Quinolinas/administración & dosificación , Acetatos/metabolismo , Administración por Inhalación , Animales , Antiasmáticos/administración & dosificación , Antiasmáticos/metabolismo , Anticoagulantes/administración & dosificación , Anticoagulantes/metabolismo , Asma/metabolismo , Ciclopropanos , Relación Dosis-Respuesta a Droga , Quimioterapia Combinada , Heparina de Bajo-Peso-Molecular/metabolismo , Mediadores de Inflamación/antagonistas & inhibidores , Mediadores de Inflamación/metabolismo , Masculino , Tamaño de la Partícula , Poliésteres/administración & dosificación , Poliésteres/metabolismo , Polietilenglicoles/administración & dosificación , Polietilenglicoles/metabolismo , Quinolinas/metabolismo , Ratas , Ratas Sprague-Dawley , SulfurosRESUMEN
Montelukast, a cysteinyl leukotriene receptor antagonist available as oral tablets, is used as a second-line therapy in asthma. In this study, we sought to enhance the availability of montelukast in the lungs by encapsulating the drug in poly (lactide-co-glycolic acid)-based (PLGA) respirable large porous particles. We determined the oral and lung specific availability of montelukast by assessing metabolic stability of the drug in the lung and liver homogenates, respectively. We similarly measured the oral and inhalational bioavailability by monitoring the pharmacokinetics and disposition of the drug in live animals. After preparing montelukast-loaded particles with various polymers, in the absence or presence of polyethylenimine (PEI-1), we characterized the particles for physical-chemical properties, entrapment efficiency, in vitro release, uptake by alveolar macrophages, deposition in the lungs, and safety after pulmonary administration. When incubated in lung or liver homogenates, the amount of intact drug in the lung homogenates was greater than that in the liver homogenates. Likewise, the extent of montelukast absorption via the lungs was greater than that via the oral route. Compared with smaller non-porous particles, large porous particles (PEI-1) were taken up by the alveolar macrophages at a lesser extent but deposited in the lungs at a greater extent. The levels of injury markers in the bronchoalveolar lavage fluid (BALF), collected from rat lungs treated with PEI-1, were no different from that in BALF collected from saline treated rats. Overall, the retention time and concentration of montelukast in the lungs can be increased by formulating the drug in large porous particles of PLGA.
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Acetatos/administración & dosificación , Acetatos/farmacología , Antiasmáticos/farmacocinética , Portadores de Fármacos/química , Ácido Láctico/química , Pulmón/metabolismo , Ácido Poliglicólico/química , Quinolinas/administración & dosificación , Quinolinas/farmacología , Administración por Inhalación , Animales , Asma/tratamiento farmacológico , Disponibilidad Biológica , Líquido del Lavado Bronquioalveolar/química , Ciclopropanos , Humanos , Macrófagos Alveolares/metabolismo , Masculino , Tamaño de la Partícula , Polietileneimina/química , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Porosidad , Ratas , Ratas Sprague-Dawley , SulfurosRESUMEN
Growth factors, chemokines, and cytokines responsible for tissue regeneration have been identified. Their therapeutic usage in humans is almost nonexistent because of the difficulty in maintaining their bioactivity in the protease-rich milieu of injured tissues. Safety concerns have ruled out the systemic administration of growth factors. Angiogenic vasculature forming in the regenerating tissues has unique molecular structures, so-called "zip/postal codes". These unique vascular zip codes provide an opportunity for target-specific delivery of systemically administered therapeutics to tissue injuries by ligands (using peptides or antibodies as a delivery vehicle) binding to these specific structures. Molecules with therapeutic potential can also be packaged into nanocarriers which then can be targeted to the desired location by placing large number of peptides on the nanoparticle. The targeted delivery of systemically administered recombinant proteins to the injured tissue is hopefully rapidly advanced to provide new therapeutics to regenerative medicine.
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Patients with pulmonary arterial hypertension (PAH) are currently treated with more than one drug. Sildenafil, a phosphodiesterase type 5 (PDE-5) inhibitor, and rosiglitazone, a peroxisome proliferator-activated receptor γ (PPAR-γ) activator, is one of those combinations that could be used in PAH. To monitor the pharmacokinetics of sildenafil in the presence of rosiglitazone, we have developed and validated a sensitive, specific and rapid liquid chromatography-tandem mass spectrometric (LC-MS/MS) method. We have used this validated method to study the pharmacokinetics of sildenafil and rosiglitazone after intravenous administration of sildenafil alone or a combination of sildenafil plus rosiglitazone to adult male Sprague-Dawley rats. Sildenafil and rosiglitazone were extracted from plasma by protein precipitation with methanol. With an octadeuterated sildenafil as the internal standard, the drugs were separated via gradient elution using a C18 column and formic acid in methanol or in water as the mobile phase with a flow rate of 0.25mL/min. Both sildenafil and rosiglitazone samples in rat plasma produced linear response, when the concentration ranged between 5 and 1000ng/mL (r(2)>0.99). The pharmacokinetics study suggests that intravenous co-administration rosiglitazone plus sildenafil increases the plasma concentration of sildenafil and extends the drug's elimination half-life.
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Cromatografía Liquida/normas , Citrato de Sildenafil/sangre , Espectrometría de Masas en Tándem/normas , Tiazolidinedionas/sangre , Administración Intravenosa , Animales , Cromatografía Liquida/métodos , Masculino , Ratas , Ratas Sprague-Dawley , Reproducibilidad de los Resultados , Rosiglitazona , Citrato de Sildenafil/administración & dosificación , Citrato de Sildenafil/análisis , Espectrometría de Masas en Tándem/métodos , Tiazolidinedionas/administración & dosificación , Tiazolidinedionas/análisisRESUMEN
PURPOSE: This study seeks to develop a liposomal formulation of diethylenetriamine NONOate (DN), a long acting nitric oxide (NO) donor, with a goal to replace inhaled NO (iNO) in the treatment of pulmonary arterial hypertension (PAH). METHODS: Liposomal formulations were prepared by a lipid film hydration method and modified with a cell penetrating peptide, CAR. The particles were characterized for size, polydispersity index (PDI), zeta potential, entrapment efficiency, storage and nebulization stability, and in-vitro release profiles. The cellular uptake and transport were assessed in rat alveolar macrophages (NR8383) and transforming growth factor ß (TGF-ß) activated rat pulmonary arterial smooth muscle cells (PASMCs). The fraction of the formulation that enters the systemic circulation, after intratracheal administration, was determined in an Isolated Perfused Rat Lung (IPRL) model. The safety of the formulations were assessed using an MTT assay and by measuring injury markers in the bronchoalveolar lavage (BAL) fluid; the pharmacological efficacy was evaluated by monitoring the changes in the mean pulmonary arterial (mPAP) and systemic pressure (mSAP) in a monocrotaline (MCT) induced-PAH rat model RESULTS: Liposome size, zeta potential, and entrapment efficiency were 171 ± 4 nm, -37 ± 3 mV, and 46 ± 5%, respectively. The liposomes released 70 ± 5% of the drug in 8 h and were stable when stored at 4°C. CAR-conjugated-liposomes were taken up more efficiently by PASMCs than liposomes-without-CAR; the uptake of the formulations by rat alveolar macrophages was minimal. DN-liposomes did not increase lung weight, protein quantity, and levels of injury markers in the BAL fluid. Intratracheal CAR-liposomes reduced the entry of liposomes from the lung to blood; the formulations produced a 40% reduction in mPAP for 180 minutes. CONCLUSION: This study establishes the proof-of-concept that peptide modified liposomal formulations of long-acting NO donor can be an alternative to short-acting iNO.
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Aerosoles/administración & dosificación , Hipertensión Pulmonar Primaria Familiar/tratamiento farmacológico , Liposomas/administración & dosificación , Donantes de Óxido Nítrico/administración & dosificación , Óxido Nítrico/administración & dosificación , Administración por Inhalación , Animales , Líquido del Lavado Bronquioalveolar/química , Química Farmacéutica/métodos , Portadores de Fármacos/química , Pulmón/efectos de los fármacos , Macrófagos Alveolares/efectos de los fármacos , Tamaño de la Partícula , RatasRESUMEN
The present study investigated the feasibility of encapsulating two drugs, fasudil and superoxide dismutase (SOD), into liposomes for targeted and inhalational delivery to the pulmonary vasculature to treat pulmonary arterial hypertension (PAH). Nanosized liposomes were prepared by a thin-film formation and extrusion method, and the drugs were encapsulated by a modified freeze-thaw technique. The peptide CARSKNKDC (CAR), a pulmonary-specific targeting sequence, was conjugated on the surface of liposomes. Formulations were optimized for various physicochemical properties, tested for their ex-vivo and in-vivo drug absorption after intratracheal administration, and evaluated for short-term safety in healthy rats. The homogenous nanosized liposomes contained both SOD (~55% entrapment) and fasudil (~40% entrapment), and were stable at 4°C and after nebulization. Liposomes released the drugs in a controlled-release fashion. Compared with plain liposomes, CAR-liposomes increased the uptake by pulmonary endothelial and smooth muscle cells by ~2-fold. CAR-liposomes extended the biological half-lives of SOD and fasudil by ~3-fold. Ex-vivo studies demonstrated that CAR-liposomes were better retained in the lungs than plain liposomes. Bronchoalveolar lavage studies indicated the safety of peptide-equipped liposomes as pulmonary delivery carriers. Overall, this study demonstrates that CAR-liposomes may be used as inhalational carriers for SOD plus fasudil-based combination therapy for PAH.
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1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/análogos & derivados , Liposomas/química , Superóxido Dismutasa/administración & dosificación , Superóxido Dismutasa/farmacocinética , Vasodilatadores/administración & dosificación , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/administración & dosificación , 1-(5-Isoquinolinesulfonil)-2-Metilpiperazina/farmacocinética , Administración por Inhalación , Animales , Líquido del Lavado Bronquioalveolar/química , Química Farmacéutica/métodos , Preparaciones de Acción Retardada , Liberación de Fármacos , Estabilidad de Medicamentos , Hipertensión Pulmonar/tratamiento farmacológico , Pulmón/irrigación sanguínea , Masculino , Nanopartículas/química , Tamaño de la Partícula , Ratas , Ratas Sprague-Dawley , Tecnología Farmacéutica/métodosRESUMEN
INTRODUCTION: Delivery of therapeutic insulin via the pulmonary route has been the most investigated non-invasive alternative to the commonly used subcutaneous (SC) route for diabetes management. Despite discontinuation of the first inhalable insulin, Exubera®, due to suboptimal market acceptance, development of orally inhaled insulin delivery systems has been galvanized by the recent approval of Afrezza® and several others awaiting approval. AREAS COVERED: The scope of this review article includes the prospects for and the challenges faced in developing inhaled insulin delivery systems; discussion of orally inhaled therapeutic insulin delivery systems that were discontinued, recently approved or are currently under active investigation; and formulation approaches that have the potential to deliver insulin via the pulmonary route. EXPERT OPINION: The pulmonary route is the most advantageous route for non-invasive insulin delivery. Inhalable insulin therapeutics have the potential to be successful, provided that the formulations can be made with modified release patterns to substitute for both prandial and basal insulin injections, the delivery devices are convenient and easy to use, and the long-term safety of inhaled insulin is documented through extensive studies.