Cryoprotection–lyophilization and physical stabilization of rifampicin-loaded flower-like polymeric micelles

Rifampicin-loaded poly(ε-caprolactone)-b-poly(ethylene glycol)-poly(ε-caprolactone) flower-like polymeric micelles display low aqueous physical stability over time and undergo substantial secondary aggregation. To improve their physical stability, the lyoprotection- lyophilization process was thoroughly characterized. The preliminary cryoprotectant performance of mono- and disaccharides (e.g. maltose, glucose), hydroxypropyl-β-cyclodextrin (HPβCD) and poly(ethylene glycol) (PEG) of different molecular weights was assessed in freeze-thawing assays at -20°C, -80°C and -196°C. The size and size distribution of the micelles at the different stages were measured by dynamic light scattering (DLS). A cryoprotectant factor (fc) was determined by taking the ratio between the size immediately after the addition of the cryoprotectant and the size after the preliminary freeze-thawing assay. The benefit of a synergistic cryoprotection by means of saccharide/ PEG mixtures was also assessed. Glucose (1 : 20), maltose (1 : 20), HPβCD (1 : 5) and glucose or maltose mixtures with PEG3350 (1 : 20) (copolymer:cryoprotectant weight ratio) were the most effective systems to protect 1 per cent micellar systems. Conversely, only HPβCD (1 : 5) cryoprotected more concentrated drug-loaded micelles (4% and 6%). Then, those micelle/ cryoprotectant systems that displayed fc values smaller than 2 were freeze-dried. The morphology of freeze-dried powders was characterized by scanning electron microscopy and atomic force microscopy and the residual water content analysed by the Karl Fisher method. The HPβCD-added lyophilisates were brittle porous cakes (residual water was between 0.8% and 3%), easily redispersable in water to form transparent systems with a minimal increase in the micellar size, as determined by DLS.Fil: Moretton, Marcela Analía. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; 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: 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

Extemporaneous clobazam suspensions for paediatric use prepared from commercially available tablets and pure drug

Dos suspensiones orales acuosas de clobazam para uso pediátrico (5 mg/ml) fueron evaluadas para determinar su estabilidad fisicoquimica bajo diferentes condiciones de almacenamiento.Two clobazam aqueous suspensions for paediatric oral usage (5 mg/ml) were investigated to determinate its physicochemical stability under different storage conditions.Fil: Buontempo, Fabian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina; Gobierno de la Ciudad de Buenos Aires. Hospital de Pediatría "Juan P. Garrahan"; Argentina;Fil: Moretton, Marcela Analía. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Quiroga, E.. Colegio de Farmacéuticos de la Provincia de Buenos Aires; Argentina;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; Argentina

Current understanding of nanoparticle toxicity mechanisms and interactions with biological systems

Nanotechnology is an emerging science involving the manipulation of matter at the nanometer scale. Nanoparticles (NP) are engineered structures with at least one dimension of 100 nm or less. These materials are progressively being used for commercial purposes and being incorporated into everyday manufactured articles at an increasing rate. These products include consumer items such as pharmaceuticals, cosmetics, food, food packaging, and household products, among others. The same unique physical and chemical properties that make NP so attractive may be associated with their potentially hazardous effects on cells and tissues. Despite the large benefit ensured from the application of nanotechnology, many issues related to NP behavior and adverse effects are not fully understood or should be examined anew. The traditional hypothesis that NP exhibit different or additional hazards due to their ?nano? size has been challenged in recent years, and NP categorization according to their properties and toxicity mechanism has been proposed instead. Possible undesirable results of these capabilities are harmful interactions with biological systems and the environment, with the potential to generate toxicity. Both in vivo and in vitro studies have shown that NP are closely associated with toxicity by increasing intracellular reactive oxygen species (ROS) levels, and/or the levels of pro-inflammatory mediators. This review summarizes available data on NP toxicity in biological systems, with particular focus on oxidative stress and inflammation as the main mechanisms that lead to adverse health effects following NP exposure.Fil: Garces, Mariana Soledad. 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: Caceres, Lourdes Catalina. 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: Chiappetta, Diego Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Magnani, Natalia Daniela. 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: Evelson, Pablo Andrés. 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; Argentin

Self-assembled Amphotericin B Pharmacosome like Vesicles Derived from Lipid-based Microtubes: a Model Carrier to Further Explore

Background: Self-assembled drug delivery systems are of much interest since they can be produced by simple low cost and solvent-free procedures. Pharmacosomes are supramolecular-structured nanocarriers with benefits for drug stability and targeting delivery. Amphotericin B (AmB) still remains an important agent for the treatment of invasive mold infections, e.g invasive aspergillo-sis, although the challenge for new formulations is still prevailing due to high rates of toxicity. Objective: We have previously reported the incorporation of AmB into 12-hydroxystearic acid lipid-based microtubes (MTs) for topical use, herein we report the ability of AmB-MTs to self-assemble into vesicles upon dilution. Methods: AmB-MTs with different drug concentrations (1, 3, 5 mg/ml) were prepared, and size de-termination was carried out for different dilutions. Morphology was evaluated by microscopy. In vitro cytotoxicity was evaluated in Vero cells and in vitro activity against Aspergillus fumigatus and Asper-gillus flavus was assessed. Results: AmB-MTs closed upon dilution to form vesicles ranging from 200 nm to 1µm. AmB MIC (Minimum inhibitory concentration) for both Aspergillus species was 0.0625 and 0.125 µg/ml for dis-persion and reconstituted lyophilized, respectively. Conclusion: AmB pharmacosome-like vesicles are smaller structures than MTs may thus be favoura-ble for other delivery routes. We assume that this kind of pharmacosomes-like carrier is a promising model for the obtention of new vesicular carriers based on lipid MTs.Fil: Salerno, Claudia. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Cuestas, María Luján. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones en Microbiología y Parasitología Médica. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones en Microbiología y Parasitología Médica; ArgentinaFil: Manco, Karina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Chiappetta, Diego Andrés. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lucangioli, Silvia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

Chitosan-Grafted Copolymers and Chitosan-Ligand Conjugates as Matrices for Pulmonary Drug Delivery

Recently, much attention has been given to pulmonary drug delivery by means of nanosized systems to treat both local and systemic diseases. Among the differentmaterials used for the production of nanocarriers, chitosan enjoys high popularity due to its inherent characteristics such as biocompatibility, biodegradability, and mucoadhesion, among others. Through the modification of chitosan chemical structure, either by the addition of new chemical groups or by the functionalization with ligands, it is possible to obtain derivatives with advantageous and specific characteristics for pulmonary administration. In this paper, we discuss the advantages of using chitosan for nanotechnology-based pulmonary delivery of drugs and summarize the most recent and promising modifications performed to the chitosan molecule in order to improve its characteristics.Fil: Andrade, Fernanda. Universidad de Porto; PortugalFil: Goycoolea, Francisco. Westfalische Wilhelms Universitat; AlemaniaFil: 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: Das Neves, José. Universidad de Porto; PortugalFil: 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; ArgentinaFil: Sarmento, Bruno. Universidad de Porto; Portugal. Instituto Superior de Ciências da Saúde-Norte; Portuga

Micro-encapsulated secretory leukocyte protease Inhibitor decreases cell-mediated immune response in autoimmune orchitis

AIMS: We previously reported that recombinant human Secretory Leukocyte Protease Inhibitor (SLPI) inhibits mitogen-induced proliferation of human peripheral blood mononuclear cells. To determine the relevance of this effect in vivo, we investigated the immuno-regulatory role of SLPI in an experimental autoimmune orchitis (EAO) model. MAIN METHODS: In order to increase SLPI half life, poly-ε-caprolactone microspheres containing SLPI were prepared and used for in vitro and in vivo experiments. Multifocal orchitis was induced in Sprague-Dawley adult rats by active immunization with testis homogenate and adjuvants. Microspheres containing SLPI (SLPI group) or vehicle (control group) were administered s.c. to rats during or after the immunization period. KEY FINDINGS: In vitro SLPI-release microspheres inhibited rat lymphocyte proliferation and retained trypsin inhibitory activity. A significant decrease in EAO incidence was observed in the SLPI group (37.5%) versus the control group (93%). Also, SLPI treatment significantly reduced severity of the disease (mean EAO score: control, 6.33±0.81; SLPI, 2.72±1.05). In vivo delayed-type hypersensitivity and ex vivo proliferative response to testicular antigens were reduced by SLPI treatment compared to control group (p=0.05). SIGNIFICANCE: Our results highlight the in vivo immunosuppressive effect of released SLPI from microspheres which suggests its feasible therapeutic use.Fil: Guazzone, Vanesa Anabella. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Guerrieri, Diego. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Jacobo, Patricia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Glisoni, Romina Julieta. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; 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: Lustig, Livia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas; ArgentinaFil: Chuluyan, Hector Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Farmacología; Argentin

Hydrolyzed Galactomannan-Modified Nanoparticles and Flower-Like Polymeric Micelles for the Active Targeting of Rifampicin to Macrophages

Inhalable nanocarriers that are uptaken by macrophages represent an appealing approach for the targeting of antibiotics to the tuberculosis reservoir. In the present work, we report on the development of rifampicin (RIF)-loaded nanoparticles and flower-like polymeric micelles surface-modified with hydrolyzed galatomannan (GalM-h), a polysaccharide of mannose and galactose, two sugars that are recognized by lectin-like receptors. Initially, pure or GalM-h-associated chitosan nanoparticles (NPs) were produced by ionotropic gelation. Despite the composition, NPs displayed positive zeta potential values between +18.0 and +24.5 mV and a size ranging between 263 and 340 nm. In addition, RIF payloads were approximately 1.0% w/w. To increase the encapsulation efficiency, a more complex nanocarrier based on poly(epsilon-caprolactone)-b-poly(ethylene-glycol)-b-poly(epsilon-caprolactone) flower-like polymeric micelles (PMs) coated with chitosan or GalM-h/chitosan were engineered. These polymeric micelles displayed a bimodal size distribution with a positive zeta potential between +6.7 and +8.1 mV. More importantly, the drug encapsulation capacity was increased 12.9-fold with respect to the NPs. An agglutination assay with concanavalin A confirmed the presence of GalM-h on the surface. Qualitative uptake studies by fluorescence microscopy revealed that GalM-h-modified systems were taken-up by RAW 264.7 murine macrophages. Finally, the intracellular/cell associated levels of RIF following the incubation of cells with free or encapsulated drug indicated that while chitosan hinders the uptake, GalM-h leads to a significant increase of the intracellular concentration.Fil: Moretton, Marcela Analía. 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: 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: Andrade, Fernanda. Universidad de Porto; Portugal;Fil: Das Neves, José. Universidad de Porto; Portugal; Instituto Superior de Ciências da Saúde-Norte. Department of Pharmaceutical Sciences. Health Sciences Research Center; Portugal;Fil: Ferreira, Domingos. Universidad de Porto; Portugal;Fil: Sarmento, Bruno. Universidad de Porto; Portugal; Instituto Superior de Ciências da Saúde-Norte. Department of Pharmaceutical Sciences. Health Sciences Research Center; Portugal;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

Radiolabeling and biological characterization of TPGS-based nanomicelles by means of small animal imaging

Introduction In recent years, nanomedicines have raised as a powerful tool to improve prevention, diagnosis and treatment of different pathologies. Among the most well investigated biomaterials, D-α-tocopheryl polyethylene glycol succinate (also known as TPGS) has been on the spot for the last decade. We therefore designed a method to biologically characterize TPGS-based nanomicelles by labeling them with 99mTc. Methods Labeling process was performed by a direct method. The average hydrodynamic diameter of TPGS nanomicelles was measured by dynamic light scattering and radiochemical purity was assessed by thin layer chromatography. Imaging: a dynamic study was performed during the first hour post radioactive micelles administration in a gamma camera (TcO4− was also administered for comparative purposes). Then two static images were acquired in ventral position: 1 h and 12 h post injection. Blood pharmacokinetics of 99mTc-TPGS during 24 h was performed. Results Images revealed whole body biodistribution at an early and delayed time and semiquantification was performed in organs of interest (%Total counts: soft tissue 6.1 ± 0.5; 3.9 ± 0.1, Bone 1.2 ± 0.2; 1.0 ± 0.1, Heart 1.5 ± 0.6; 0.7 ± 0.3, Kidneys 16.6 ± 1.3; 26.5 ± 1.7, Liver 8.6 ± 1.1; 11.1 ± 0.1 for 1 and 12 h post injection respectively). Conclusion This work demonstrated that TPGS based nanomicelles are susceptible to be radiolabeled with 99mTc thus they can be used to perform imaging studies in animal models. Moreover radiolabeling of these delivery nano systems reveals their possibility to be used as diagnostic agents in the near future.Fil: Tesan, Fiorella Carla. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Portillo, Mariano Gastón. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Moretton, Marcela Analía. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Bernabeu, Ezequiel Adrian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Chiappetta, Diego Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Salgueiro, María Jimena. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Zubillaga, Marcela Beatriz. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

Development and characterization of soluplus® nanomicelles associated to specific igg as an innovative strategy for the detection and neutralization of shiga toxin type 2

Shiga toxin type 2 (Stx2) is the main virulence factor of Shiga toxinproducing Escherichia coli and is responsible for triggering HemolyticUremic Syndrome (HUS). We aimed to develop and characterizepolymeric nanomicelles (PN) with the amphiphilic polymerSoluplus® coupled to anti-Stx2 IgG in order to introduce innovativeproposals for the detection of Stx2 and treatment of HUS. PN ofSoluplus® were formulated in PBS and coupled with IgG anti Stx2from hyperimmune (PN-IgG-Stx2) or control bovine colostrum (PNIgG-Ctrl). The hydrodynamic size of PN, PN-IgG-Stx2 and PN-IgGCtrlwas evaluated by Dynamic Light Scattering. Morphology of PNor PN-IgG-Stx2 was analyzed by Transmission Electron Microscopy(TEM). The PN toxicity was evaluated on both Vero and Human GlomerularEndothelial cells (HGEC) and cell viability was determinedby neutral red uptake. After coupling PN with IgG, Stx2 neutralizationcapacity of PN-IgG-Stx2 or PN-IgG-Ctrl was evaluated on Vero andHGEC cells and the percentage of cell viability was analyzed. Thehydrodynamic size of the PN of Soluplus® and IgG-Stx2 showed anaverage diameter of 70.2 ± 1.5 nm and 40.9 ± 2 nm, respectively.When both components were coupled, a single peak with a similarhydrodynamic size of the PN was observed (70.4 ± 0.2 nm). TEManalysis revealed circular particles with a diameter corresponding to100 nm either in PN and PN-IgG-Stx2 particles. PN-IgG-Stx2 wereable to neutralize Stx2 on Vero and HGEC cells in a dose dependentmanner. When comparing the neutralization capacity of Stx2 by IgGStx2vs PN-IgG-Stx2 a significant improvement in the cell viabilityof Vero and HGEC was observed with the PN-IgG-Stx2 (p<0.001).The association between anti-Stx2 IgG from bovine colostrum andSoluplus® PN was optimized and characterized. Encouraging resultsof antibody functionality coupled with PN were registered.These results may open the perspective of the design of new nanoplatformsfor neutralization and/or detection of Stx2.Fil: Girón Reyes, Claudio Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Gomez, Fernando Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Amaral, María Marta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Chiappetta, Diego Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Moretton, Marcela Analía. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ibarra, Cristina Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaFil: Sacerdoti, Flavia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Fisiología y Biofísica Bernardo Houssay. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Fisiología y Biofísica Bernardo Houssay; ArgentinaLXVI Reunión Anual de la Sociedad Argentina de Investigación Clínica; LXIX Reunión Anual de la Sociedad Argentina de Inmunología; LIII Reunión Anual de la Asociación Argentina de Farmacología Experimental y XI Reunión Anual de la Asociación Argentina de NanomedicinasArgentinaSociedad Argentina de Investigación ClínicaSociedad Argentina de InmunologíaAsociación Argentina de Farmacología ExperimentalAsociación Argentina de Nanomedicina

Cardioprotective Effects of Chronic Release Formulations of Subcutaneous Implants of Carvedilol in Spontaneously Hypertensive Rats

Introducción: En nuestro laboratorio hemos desarrollado implantes subcutáneos de carvedilol capaces de mantener niveles lasmáticos sostenidos del β-bloqueante durante 3 semanas. Objetivo: Evaluación de la liberación in vivo y la eficacia cardioprotectora de implantes subcutáneos de carvedilol desarrollados con poliepsilon- caprolactona (PCL) y Soluplus (SP) en ratas espontáneamente hipertensas (REH). Materiales y métodos: Se utilizaron 12 REH macho (250-300 g), a las cuales se colocó un implante subcutáneo cada 3 semanas de PCL: SP 100:50 mg (control, n = 6) o carvedilol: PCL:SP (100mg:100mg:50mg) (carvedilol, n = 6). Se evaluó el perfil plasmático y el efecto sobre la presión arterial sistólica (PAS) durante 62 días. Al final del tratamiento, se realizaron determinaciones ecocardiográficas y la medición de la PAS y. la presión arterial media (PAM) directas. Resultados: El grupo que recibió el implante conteniendo 100 mg de carvedilol presentó concentraciones plasmáticas del fármaco en el rango de 100- 500 ng/mL a lo largo de 62 días de tratamiento, luego del cual la PAS fue 20 mmHg menor que en el grupo control (217 ± 3 mmHg vs. 237 ± 6 mmHg; p <0,05). Las PAS y PAM directas fueron significativamente menores el grupo tratado que en el control. El implante de carvedilol 100 mg redujo la variabilidad de la presión arterial (VPA) de corto plazo en comparación con el control. Parámetros ecocardiográficos como la fracción de eyección del ventrículo izquierdo (FEVI), fracción de acortamiento, y relación E/A fueron significativamente mayores en las ratas tratadas. El peso del VI fue menor en las ratas que recibieron el implante con carvedilol. Conclusión: Los implantes conteniendo CAR/PCL/SP (100:100:50) mg aportan niveles plasmáticos terapéuticos de carvedilol y estables durante el transcurso del tratamiento, los cuales se correlacionan con una disminución significativa y sostenida de los valores de PA indirecta. El tratamiento con los implantes de carvedilol logró atenuar los valores de PA directa y su variabilidad en las REH. Se demostró que el tratamiento con los implantes ejerció un efecto cardioprotector evidenciado en el ecocardiograma y por una reducción de la hipertrofia ventricular izquierda.Background: In our laboratory, we have developed subcutaneous implants of carvedilol capable of maintaining stable concentrations of the β-blocker during 3 weeks.Objective: The aim of this study was to evaluate the in vivo release and the cardioprotective efficacy of subcutaneous implants of carvedilol developed with poly-epsilon-caprolactone (PCL) and Soluplus (SP) polymers in spontaneously hypertensive rats (SHR).Methods: Twelve spontaneously hypertensive male rats (250-300 g) underwent placement of subcutaneous implant of PCL:SP 100:50 mg (control group, n = 6) or carvedilol:PCL:SP (100mg:100mg:50mg) (carvedilol group, n = 6), every 3 weeks. The plasma profile of each implant and its effect on systolic blood pressure (SBP) was evaluated for 62 days. At the end of treatment, echocardiographic parameters were determined, and direct SBP and direct mean arterial pressure (MAP) were measured.Results: The group that received the implant containing 100 mg of carvedilol presented plasma concentrations of the drug in the range of 100- 500 ng/mL throughout 62 days of treatment, after which the SBP was 20 mmHg lower than in the control group (217±3 mm Hg vs. 237 ± 6 mm Hg; p <0.05). Direct SBP and MAP were significantly lower in the treated group than in the controlgroup. The implant loaded with carvedilol 100 mg reduced short-term blood pressure variability (BPV) in SHR compared with the control group. Echocardiographic parameters as left ventricular ejection fraction (LVEF), shortening fraction and E/A ratio were significantly greater in treated rats. Left ventricular weight was lower in the rats with carvedilol implant.Conclusion: Implants containing CAR/PCL/SP (100:100:50) mg provide therapeutic and stable plasma levels of carvedilol during treatment, which correlate with a significant and sustained decrease in indirect BP values. Treatment with carvedilol implants attenuated direct BP values and blood pressure variability in SHR. Treatment with implant produced cardioprotective effects evidenced in the echocardiogram by a reduction in left ventricular hypertrophy.Fil: Allo, Miguel Angel. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Santander Plantamura, Yanina Alejandra. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Bernabeu, Ezequiel Adrian. 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: Bin, Eliana Pamela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Moretton, Marcela Analía. 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: Carranza, Andrea. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; ArgentinaFil: Chiappetta, Diego Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Tecnología Farmacéutica; ArgentinaFil: Höcht, Christian. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Farmacología; Argentin