A highly concentrated and taste-improved aqueous formulation of efavirenz for a more appropriate pediatric management of the anti-HIV therapy

Pediatric HIV is scarce in developed countries; 90% of pediatric HIV patients are in developing countries. In contrast, children represent 15% of the new infections in poor countries. Approximately 90% of the HIV-positive children do not have access to antiretrovirals (ARVs). Without treatment, 50% of the patients die before the 2 years of age. Efavirenz (EFV, aqueous solubility ~4 μg/mL, 40-45% bioavailability), a non-nucleoside reverse transcriptase inhibitor (NNRTI), is a first-choice pediatric ARV. To assure therapeutic plasma concentrations, the low oral bioavailability demands the administration of relatively high EFV doses. Aqueous EFV irritates the oral mucosa, causing a Burning Mouth Syndrome (BMS). A triglyceride-based liquid formulation of EFV (30 mg/mL) is not commercially available worldwide, making the appropiate dose adjustment and the swallowing difficult. More importantly, clinical trials indicated that the oral bioavailability of this oily solution is lower than that of the solid one. Moreover, a relatively high inter-subject variability has been found. The present work reports the development and full characterization of a concentrated (20 mg/mL, 2%) and taste-masked aqueous formulation of EFV for a more appropriate management of the pediatric anti-HIV therapy. Formulations displayed high physicochemical stability over time under regular storage conditions. Release assays in vitro showed a burst effect (2 h) and zero-order kinetics later on (between 2 and 24 h), compatible with the oral administration route and release. Finally, taste tests performed by adult healthy volunteers indicated that the unique combination of flavors and sweeteners employed (i) reduced the intensity of the BMS and (ii) shortened its duration significantly. Overall results indicate that the cost-effective and scalable nanotechnological strategy proposed could enable the more covenient and compliant administration of lower EFV doses. Due to a better pharmacokinetic profile, this would result in similar plasma levels than higher doses administered in solid or triglyceridesoluble form. In this context, some reduction of the treatment cost can be envisioned. This could improve the access of less affluent pediatric patients to medication in poor countries.Fil: Chiappetta, Diego Andrés. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Hocht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Sosnik, Alejandro Dario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Efavirenz-loaded polymeric micelles for pediatric anti-HIV pharmacotherapy with significantly higher oral bioavailability

Children constitute the most challenging population in anti-HIV/AIDS pharmacotherapy. Efavirenz (EFV; aqueous solubility 4 µg/ml, bioavailability 40–45%) is a first-line agent in the pediatric therapeutic cocktail. The liquid formulation of EFV is not available worldwide, preventing appropriate dose adjustment and more convenient administration. The bioavailability of liquid EFV is lower than that of the solid formulation. Improving the bioavailability of the drug would reduce the cost of treatment and enable less affluent patients to access this drug. Aim: To encapsulate EFV in polymeric micelles to improve the aqueous solubility and the the oral bioavailability of the drug. Methods: EFV was incorporated into the core of linear and branched poly(ethylene oxide)–poly(propylene oxide) block copolymer micelles. The size and size distribution of the drug-loaded aggregates were characterized by dynamic light scattering and the morphology by transmission electron microscopy. The bioavailability of the EFV-loaded micellar system (20 mg/ml) was assessed in male Wistar rats (40 mg/kg) and compared to that of a suspension prepared with the content of EFV capsules in 1.5% carboxymethylcellulose PBS solution (pH 5.0), and an EFV solution in a medium-chain triglyceride (Miglyol® 812). Results: This work demonstrates that the encapsulation of EFV, which is poorly water soluble, into polymeric micelles of different poly(ethylene oxide)–poly(propylene oxide) block copolymers significantly improves the oral bioavailability of the drug, and reduces the interindividual variability. Conclusion: This strategy appears a very promising one towards the development of a liquid aqueous EFV formulation for the improved pediatric HIV pharmacotherapy.Fil: Chiappetta, Diego Andrés. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Hocht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Taira, Carlos Alberto. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sosnik, Alejandro Dario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Neurochemical, behavioral, and neurogenic validation of a hyposerotonergic animal model by voluntary oral consumption of PCPA

The inhibitor of tryptophan hydroxylase, para-chlorophenylalanine (PCPA), has been classically employed as a pharmacological tool to deplete serotonin (5-HT) in animal models and to evaluate whether this neurotransmitter is involved in the action of pharmacological compounds. PCPA is usually administrated by intraperitoneal (ip) injections, which are stressful and painful. To avoid ip injections, we designed and validated a protocol for PCPA oral administration. C57BL/6 elite male mice received PCPA during 7 days either ip or by giving the drug inside jelly cubes at an estimated dose of 500 mg/kg on days 1 and 2 and 250 mg/kg for the rest of the treatment. 5-HT levels decreased by 85% and 55% in the hippocampus of mice treated with oral or ip PCPA, respectively, whereas in the prefrontal cortex, 5-HT levels decreased by 65% (oral) and 50% (ip). Behavioral tests, like the forced swimming test (FST), the nestlet shredding test (NST), and the marble burying test (MBT), were performed. In the FST, mice received fluoxetine ip 30 min before the test. In mice with oral PCPA treatment, fluoxetine did not induce significant reductions of immobility, indicating that reduction of 5-HT levels was effective. No effect of ip or oral 5-HT depletion was observed in the NST nor in the MBT. In a second experiment, mice received oral PCPA for 8 weeks: again, serotonin levels were significantly decreased in both hippocampus and cortex, and effects on hippocampal neurogenesis replicated previous observations in hyposerotonergic mice. Therefore, neurochemical, behavioral, and neurogenic results allow us to validate this refined protocol for voluntary oral consumption of PCPA.Fil: Foltran, Rocío Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Stefani, Karen Melany. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; ArgentinaFil: Hocht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Diaz, Silvina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Biología Celular y Neurociencia "Prof. Eduardo de Robertis". Universidad de Buenos Aires. Facultad de Medicina. Instituto de Biología Celular y Neurociencia; Argentin

Intranasal administration of antiretroviral-loaded micelles for anatomical targeting to the brain in HIV

We investigated the intranasal administration of poly(ethylene oxide)–poly(propylene oxide) polymeric micelles loaded with high payloads of the first-line antiretroviral drug efavirenz for targeting to the CNS. The effect of micellar size and composition and drug payload was assessed, employing simple micelles made of a highly hydrophilic copolymer, poloxamer F127, loaded with 20 mg/ml drug and mixed micelles containing 75% of a medium hydrophobic poloxamine, T904, and 25% F127 loaded with 20 and 30 mg/ml drug, respectively. F127 confers high physical stability, while T904 substantially improves the encapsulation capacity of the micelles. The bioavailability of the drug in the CNS was increased fourfold and the relative exposure index (ratio between the area-under-the-curve in the CNS and plasma) was increased fivefold with respect to the same system administered intravenously. These findings demonstrate the potential of this scalable and cost-viable strategy to attack the HIV sanctuary in the CNS.Fil: Chiappetta, Diego Andrés. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina;Fil: Hocht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; Argentina;Fil: Opezzo, Javier A. W.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; Argentina;Fil: Sosnik, Alejandro Dario. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina

Dual role of serotonin in the acquisition and extinction of reward-driven learning: involvement of 5-HT1A, 5-HT2A and 5-HT3 receptors

Serotonin (5-HT) has been proposed as a possible encoder of reward. Nevertheless, the role of this neurotransmitter in reward-based tasks is not well understood. Given that the major serotonergic circuit in the rat brain comprises the dorsal raphe nuclei and the medial prefrontal cortex (mPFC), and because the latter structure is involved in the control of complex behaviors and expresses 1A (5-HT1A), 2A (5-HT2A), and 3 (5-HT3) receptors, the aim was to study the role of 5-HT and of these receptors in the acquisition and extinction of a reward-dependent operant conditioning task. Long Evans rats were trained in an operant conditioning task while receiving fluoxetine (serotonin reuptake inhibitor, 10 mg/kg), tianeptine (serotonin reuptake enhancer, 10 mg/kg), buspirone (5-HT1A partial agonist, 10 mg/kg), risperidone (5-HT2A antagonist, 1 mg/kg), ondansetron (5-HT3 antagonist, 2 mg/kg) or vehicle. Then, animals that acquired the operant conditioning without any treatment were trained to extinct the task in the presence of the pharmacological agents. Fluoxetine impaired acquisition but improved extinction. Tianeptine administration induced the opposite effects. Buspirone induced a mild deficit in acquisition and had no effects during the extinction phase. Risperidone administration resulted in learning deficits during the acquisition phase, although it promoted improved extinction. Ondansetron treatment showed a deleterious effect in the acquisition phase and an overall improvement in the extinction phase. These data showed a differential role of 5-HT in the acquisition and extinction of an operant conditioning task, suggesting that it may have a dual function in reward encoding.Fil: Frick, Luciana Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Bernardez Vidal, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Hocht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Zanutto, Bonifacio Silvano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Rapanelli, Maximiliano. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); Argentin

Tetronic® 904-containing polymeric micelles overcome the overexpression of ABCG2 in the blood-brain barrier of rats and boost the penetration of the antiretroviral efavirenz into the central nervous system

Aim: To assess the involvement of ABCG2 in the pharmacokinetics of efavirenz in the blood–brain barrier (BBB) and investigate a nanotechnology strategy to overcome its overexpression under a model of chronic oral administration. Materials & methods A model of chronic efavirenz (EFV) administration was established in male Sprague–Dawley rats treated with a daily oral dose over 5 days. Then, different treatments were conducted and drug concentrations in plasma and brain measured. Results: Chronic treatment with oral EFV led to the overexpression of ABCG2 in the BBB that was reverted after a brief washout period. Moreover, gefitinib and the polymeric amphiphile Tetronic® 904 significantly inhibited the activity of the pump and potentiated the accumulation of EFV in CNS. The same effect was observed when the drug was administered within mixed micelles containing TetronicT904 as the main component. Conclusion: Tetronic 904-containing polymeric micelles overcame the overexpression of ABCG2 in the BBB caused by chronic administration of EFV then boosting its penetration into the CNS.Fil: Roma, Martín Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas (i); Argentina. Universidad de Buenos Aires; ArgentinaFil: Hocht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Chiappetta, Diego Andrés. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Di Gennaro, Stefania S.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas (i); Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Minoia, Juan Mauricio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas (i); Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Bramuglia, Guillermo F.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Rubio, Modesto Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas (i); Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Sosnik, Alejandro Dario. Technion - Israel Institute Of Technology; IsraelFil: Peroni, Roxana Noemi. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Farmacológicas (i); Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; Argentin

Effects of third generation beta-blockers, atenolol or amlodipine on blood pressure variability and target organ damage in spontaneously hypertensive rats

Background: b-blockers are no longer considered as firstline antihypertensive drugs due to their lower cardioprotection. Method: Considering the differences in the pharmacological properties of b-blockers, the present work compared the effects of third-generation bblockers – carvedilol and nebivolol – with a first-line agent – amlodipine – on hemodynamic parameters, including short-term blood pressure variability (BPV), and their ability to prevent target organ damage in spontaneously hypertensive rats (SHR). SHR rats were orally treated with carvedilol, nebivolol, atenolol, amlodipine or vehicle for 8 weeks. Wistar Kyoto rats treated with vehicle were used as normotensive group. Echocardiographic evaluation, BP, and short-term BPV measurements were performed. Left ventricle and thoracic aorta were removed for histological evaluations and to assess the expression of transforming growth factor b (TGF-b), tumor necrosis factor-a (TNF-a) and interleukin-6 (IL-6). Results: Carvedilol, nebivolol or amlodipine induced a greater reduction of carotid BP, short-term BPV and echocardiography parameters than atenolol in SHR rats. Carvedilol, nebivolol and amlodipine were more effective than atenolol in the prevention of cardiac hypertrophy, and cardiac and aortic collagen deposit. Carvedilol and nebivolol, but not atenolol, reduced the expressions of fibrotic and inflammatory biomarkers – TGF-b, TNF-a and IL-6 – in SHR rats to a similar extent to that of amlodipine. Conclusion: Chronic treatment with carvedilol or nebivolol attenuates carotid BP and short-term BPV, and reduces target organ damage in SHR to a greater extent than atenolol. Our findings suggest that the lower cardiovascular protection of nonvasodilating b-blockers, as atenolol, in hypertension must not be translated to thirdgeneration b-blockers. Keywords: amlodipine, atenolol, blood pressure variability, carvedilol, nebivolol, spontaneously hypertensive rats, target organ damage Abbreviations: BP, blood pressure; BPV, blood pressure variability; CV, coefficient of variation; D. Post. WT, diastolic posterior wall thickness; HR, heart rate; ICF, interstitial collagen fraction; IL-6, interleukin-6; IVRT, isovolumic relaxation time; LVEDD, left ventricular end diastolic diameter; LV, left ventricular; LVWT, left ventricular wall thickness; SHR, spontaneously hypertensive rats; TGF-b, transforming growth factor b; TNF-a, tumor necrosis factor-a; TOD, target organ damage; TPGS, D-a-tocopheryl polyethylene glycol 1000 succinate; WKY, Wistar KyotoFil: del Mauro, Julieta Sofía. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Prince, Paula Denise. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; ArgentinaFil: Allo, Miguel Angel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Santander Plantamura, Yanina Alejandra. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Moretton, Marcela Analía. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: González, Germán Esteban. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiopatología Cardiovascular; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Bertera, Facundo Martin. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Fisiopatología y Bioquímica Clínica; ArgentinaFil: Carranza, Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Gorzalczany, Susana Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Chiappetta, Diego Andrés. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Morales, Celina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiopatología Cardiovascular; ArgentinaFil: Gelpi, Ricardo Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Bioquímica y Medicina Molecular. Universidad de Buenos Aires. Facultad Medicina. Instituto de Bioquímica y Medicina Molecular; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiopatología Cardiovascular; ArgentinaFil: Taira, Carlos Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Polizio, Ariel Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; ArgentinaFil: Donato, Martin Alejandro. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiopatología Cardiovascular; ArgentinaFil: Hocht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología. Cátedra de Farmacología; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Fisiopatología y Bioquímica Clínica; Argentin