Search

Melanin is an insoluble, amorphous polymer that forms planar sheets that aggregate naturally to create colloidal particles with several biological functions. Based on this, here, a preformed recombinant melanin (PRM) was utilized as the polymeric raw material to generate recombinant melanin nanoparticles (RMNPs). These nanoparticles were prepared using bottom-up (nanocrystallization—NC, and double emulsion–solvent evaporation—DE) and top-down (high-pressure homogenization—HP) manufacturing approaches. The particle size, Z-potential, identity, stability, morphology, and solid-state properties were evaluated. RMNP biocompatibility was determined in human embryogenic kidney (HEK293) and human epidermal keratinocyte (HEKn) cell lines. RMNPs prepared by NC reached a particle size of 245.9 ± 31.5 nm and a Z-potential of −20.2 ± 1.56 mV; 253.1 ± 30.6 nm and −39.2 ± 0.56 mV compared to that obtained by DE, as well as RMNPs of 302.2 ± 69.9 nm and −38.6 ± 2.25 mV using HP. Spherical and solid nanostructures in the bottom-up approaches were observed; however, they were an irregular shape with a wide size distribution when the HP method was applied. Infrared (IR) spectra showed no changes in the chemical structure of the melanin after the manufacturing process but did exhibit an amorphous crystal rearrangement according to calorimetric and PXRD analysis. All RMNPs presented long stability in an aqueous suspension and resistance to being sterilized by wet steam and ultraviolet (UV) radiation. Finally, cytotoxicity assays showed that RMNPs are safe up to 100 μg/mL. These findings open new possibilities for obtaining melanin nanoparticles with potential applications in drug delivery, tissue engineering, diagnosis, and sun protection, among others.

The search for materials and process parameters capable of generating hydrogels for soft tissue engineering applications, based on an experimental design strategy that allows the evaluation of several factors involved in their development and performance, has greatly increased. Nevertheless, the fabrication technique can influence their mechanical properties, swelling, crystallinity, and even their susceptibility to contamination by microorganisms, compromising their performance within the tissue or organ. This study aimed to evaluate the influence of the freeze/thaw technique on different characteristics of polyvinyl alcohol-xanthan gum hydrogel. Methods: this research analyzed the critical variables of the freeze/thaw process through a systematic study of a 2

Nanoconfinement is a recent strategy to enhance solubility and dissolution of active pharmaceutical ingredients (APIs) with poor biopharmaceutical properties. In this work, we combine the advantage of cocrystals of racemic praziquantel (PZQ) containing a water-soluble coformer (i.e., increased solubility and supersaturation) and its confinement in a mesoporous silica material (i.e., increased dissolution rate). Among various potential cocrystalline phases of PZQ with dicarboxylic acid coformers, the cocrystal with glutaric acid (PZQ-GLU) was selected and successfully loaded by the melting method into nanopores of SBA-15 (experimental pore size of 5.6 nm) as suggested by physical and spectroscopic characterization using various complementary techniques like N

Inherited ichthyoses are a group of etiologically heterogeneous diseases that affect the function of the skin and that are classified as syndromic and non-syndromic entities. Irrespective of the type, all these disorders are generally produced by mutations in genes involved in a variety of cellular functions in the skin. These mutations lead to disruption of the stratum corneum and impairment of the skin barrier, producing clinical features such as hyperkeratosis, skin scaling, erythema, fissures, pruritus, inflammation, and skin pain. Despite advances in the knowledge of the pathogenesis of ichthyoses, there is, to our knowledge, no definitive cure for skin manifestations, and current treatments consist of moisturizers, emollients, and keratolytic agents. In this respect, the development of new formulations based on nanotechnology could be useful to enhance their therapeutic effectiveness. In this article, we provide a comprehensive description of pharmacological treatments for cutaneous manifestations in patients with inherited ichthyosis and discuss novel approaches with therapeutic potential for this purpose. Moreover, we offer an overview of toxicity concerns related to these treatments.

Parkinson's disease (PD) is one of the most prevalent neurodegenerative disorders worldwide. It is caused by the degeneration of dopaminergic neurons from the substantia nigra pars compacta. This neuronal loss causes the dopamine deficiency that leads to a series of functional changes within the basal ganglia, producing motor control abnormalities. L-DOPA is considered the gold standard for PD treatment, and it may alleviate its clinical manifestations for some time. However, its prolonged administration produces tolerance and several severe side effects, including dyskinesias and gastrointestinal disorders. Thus, there is an urgent need to find effective medications, and current trends have proposed some natural products as emerging options for this purpose. Concerning this, curcumin represents a promising bioactive compound with high therapeutic potential. Diverse studies in cellular and animal models have suggested that curcumin could be employed for the treatment of PD. Therefore, the objective of this narrative mini-review is to present an overview of the possible therapeutic effects of curcumin and the subjacent molecular mechanisms. Moreover, we describe several possible nanocarrier-based approaches to improve the bioavailability of curcumin and enhance its biological activity.

The skin is the largest organ in the human body, and due to its barrier function, it is susceptible to multiple injuries. The appearance of infections during the wound healing process is a complication that represents a formidable hospital challenge. The presence of opportunistic bacteria with sophisticated resistance mechanisms is difficult to eradicate and compromises patients' lives. Therefore, the search for new efficacious treatments from natural sources that prevent and counteract infections, in addition to promoting the healing process, has increased in recent years. In this respect, films with the capability to protect wounds and release drugs are the presentation that predominates commercially in the hospital environment. Those films can offer several mechanical advantages such as physical protection to prevent opportunistic bacteria's entry, regulation of gas exchange, and capture of exudate through a swelling process. Wound dressings are generally curative materials easily adaptable to different anatomical regions, with high strength and elasticity, and some are even bioabsorbable. Additionally, the components of the films can actively participate in promoting the healing process. Even more, the film can be made up of carriers with other active participants to prevent and eradicate infections. Therefore, the extensive versatility, practicality, and usefulness of films from natural sources to address infectious processes during wound healing are relevant and recurrent themes. This work presents an analysis of the state-of-the-art of films with natural products focused on preventing and eradicating infections in wound healing.

Today, the proposal for self-healing biomaterials suitable for application in engineering for soft tissues with low mechanical stress such as in brain, adipose tissue or thyroid has prominently increased. In this study, a self-healing PG-150 distearate-PVA hydrogel was developed through the freezing/thawing method and characterized. The developed hydrogel proved higher crystallinity than the control hydrogel (without freezing/thawing cycle). Furthermore, the hydrogel presented adequate chemical and mechano-responsive properties, allowing it to maintain its structure when sudden impact was subjected. In addition, the hydrogel was capable of deforming under low levels of mechanical stress, making it an excellent option as tissue engineering material.

A thermo-responsive hydrogel of Pluronic F-127, containing PLGA nanoparticles loaded with a platelet lysate for wound treatment, was prepared. A high rate of incorporation of the lysate (about 80%) in the nanoparticles was achieved by the double emulsion-solvent evaporation method. The nanoparticles were characterized by measuring their size (about 318 nm), polydispersity index (0.29) and Z potential (-17.6), as well as by infrared and calorimetric techniques, and determining their stability as a function of time. It was found through measures of transepidermal water loss that the hydrogel containing the nanoparticles was capable of providing a semi-occlusive environment, necessary for the recovery of a wound. The inclusion of lysate in nanoparticles and this in turn in the hydrogel allowed a gradual release, which would avoid contact of the total dose with the biological medium. Studies with fibroblasts and in vivo in mice showed that the hydrogel containing nanoparticles with platelet lysate promoted faster tissue regeneration than the lysate in its free form, so this system is presented as a good alternative for the treatment of wounds.

The blood-brain barrier (BBB) is a sophisticated and very selective dynamic interface composed of endothelial cells expressing enzymes, transport systems, and receptors that regulate the passage of nutrients, ions, oxygen, and other essential molecules to the brain, regulating its homeostasis. Moreover, the BBB performs a vital function in protecting the brain from pathogens and other dangerous agents in the blood circulation. Despite its crucial role, this barrier represents a difficult obstacle for the treatment of brain diseases because many therapeutic agents cannot cross it. Thus, different strategies based on nanoparticles have been explored in recent years. Concerning this, chitosan-decorated nanoparticles have demonstrated enormous potential for drug delivery across the BBB and treatment of Alzheimer’s disease, Parkinson’s disease, gliomas, cerebral ischemia, and schizophrenia. Our main objective was to highlight the high potential of chitosan adsorption to improve the penetrability through the BBB of nanoformulations for diseases of CNS. Therefore, we describe the BBB structure and function, as well as the routes of chitosan for crossing it. Moreover, we define the methods of decoration of nanoparticles with chitosan and provide numerous examples of their potential utilization in a variety of brain diseases. Lastly, we discuss future directions, mentioning the need for extensive characterization of proposed nanoformulations and clinical trials for evaluation of their efficacy.

This work presents an evaluation of the adsorption/infiltration process in relation to the loading of a model protein, α-amylase, into an assembled biodegradable polymeric system, free of organic solvents and made up of poly(D,L-lactide-co-glycolide) acid (PLGA). Systems were assembled in a friendly aqueous medium by adsorbing and infiltrating polymeric nanoparticles into porous microspheres. These assembled systems are able to load therapeutic amounts of the drug through adsorption of the protein onto the large surface area characteristic of polymeric nanoparticles. The subsequent infiltration of nanoparticles adsorbed with the protein into porous microspheres enabled the controlled release of the protein as a function of the amount of infiltrated nanoparticles, since the surface area available on the porous structure is saturated at different levels, thus modifying the protein release rate. Findings were confirmed by both the BET technique (N2 isotherms) and in vitro release studies. During the adsorption process, the pH of the medium plays an important role by creating an environment that favors adsorption between the surfaces of the micro- and nano-structures and the protein. Finally, assays of α-amylase activity using 2-chloro-4-nitrophenyl-α-D-maltotrioside (CNP-G3) as the substrate and the circular dichroism technique confirmed that when this new approach was used no conformational changes were observed in the protein after release.

Background The lack of an outright treatment for Parkinson's disease (PD) is a pivotal concern in medicine and has driven the search for novel alternatives for treating the disease. Among the proposed approaches, small interfering RNA (siRNA)-based therapy is attracting significant attention as a potential method for the treatment of PD; however, siRNAs delivery possesses potential drawbacks, such as reduced stability in blood circulation and low capacity for reaching the target site. Objective This review aims to explore siRNA-based approaches to PD and the latest advances for designing nanoparticles that effectively target siRNAs to the action site and that protect these against degradation in blood circulation. Results siRNA-based approaches provide an interesting option for designing new strategies for treating PD through the silencing of genes, whose abnormal expressions contribute to the pathophysiology of the disease; however, siRNA delivery to the brain is a key issue that remains unsolved to date. Current research efforts are focused on designing vectors that effectively transport and protect siRNAs. In this regard, nanoparticles are being developed as carriers for siRNAs with controlled delivery efficiency and low toxicity profiles, and these represent an alternative to common vectors. Conclusion Identification of putative gene targets for siRNA therapy of PD has set the pace for researching non-viral vectors; however, the technological aspects for tackling the challenge that siRNAs targeting to the brain represents are essentials. In this respect, the formulation of siRNAs in nanoparticles would avoid harmful side effects, such as immunogenic and oncogenic drawbacks.

Se prepararon nanoparticulas polimericas (NPs) de etilcelulosa por la tecnica de desplazamiento de disolvente usando etanol como disolvente. La optimizacion del metodo incluyo evaluacion de la velocidad de agitacion y el tipo de estabilizante. Se obtuvieron NPs de 142.1 a 226.5 nm en un modo reproducible y eficiente (95% eficiencia del proceso) y con buena estabilidad (a temperatura ambiente). Ademas, se utilizo un dispositivo de recirculacion con la finalidad de obtener dispersiones concentradas por un proceso continuo con potencial de escalamiento. Este metodo se reto para encapsular una molecula hidrofilica antiviral modelo (acido glicirricinico) teniendo como resultado bajas eficiencias de encapsulamiento (aproximadamente 1%). Los resultados indican que se obtienen NPs de etilcelulosa por este metodo simple y economico que ofrece la posibilidad de transportar diferentes agentes para su aplicacion en alimentos, cosmeticos o productos farmaceuticos

This study aimed to prepare poly (d,l-lactide-co-glycolide) (PLGA) nanoparticles (NPs) with chitosan (CTS) surface modification to be used as a vaginal delivery system for antimycotic drugs. Clotrimazole was encapsulated with entrapment efficiencies of 86.1 and 68.9% into Clotrimazole-PLGA-NPs (CLT-PLGA-NPs) and PLGA-NPs with CTS-modified surface (CLT-PLGA-CTS-NPs), respectively. The later NPs exhibited a larger size and higher positive zeta potential (Z potential) in comparison to unmodified NPs. In vitro release kinetic studies indicated that Clotrimazole was released in percentages of >98% from both nanoparticulate systems after 18days. Antifungal activity and mucoadhesive properties of NPs were enhanced when CTS was added onto the surface. In summary, these results suggested that Clotrimazole loaded into PLGA-CTS-NPs has great potential for vaginal applications in treating vaginal infections generated by Candida albicans.

Traditional vaginal preparations reside in the vaginal cavity for relatively a short period of time, requiring multiple doses in order to attain the desired therapeutic effect. Therefore, mucoadhesive systems appear to be appropriate to prolong the residence time in the vaginal cavity. In the current study, mucoadhesive nanoparticles based on poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA) intended for vaginal delivery of glycyrrhizic acid (GA) (a drug with well-known antiviral properties) were prepared and characterized. Nanoparticles were generated by a solvent displacement method. Incorporation of GA was performed during nanoprecipitation, followed by adsorption of drug once nanoparticles were formed. The prepared nanoparticles were characterized in terms of size, Z-potential, morphology, drug loading, interaction of GA with PVM/MA (by differential scanning calorimetry) and the in vitro interaction of nanoparticles with pig mucin (at two pH values, 3.6 and 5; with and without GA adsorbed). The preparation method led to nanoparticles of a mean diameter of 198.5 ± 24.3 nm, zeta potential of -44.8 ± 2.8 mV and drug loading of 15.07 ± 0.86 µg/mg polymer. The highest mucin interaction resulted at pH 3.6 for nanoparticles without GA adsorbed. The data obtained suggest the promise of using mucoadhesive nanoparticles of PVM/MA for intravaginal delivery of GA.

Sergio Alcalá-Alcalá, Zaida Urbán-Morlán, Irene Aguilar-Rosas, David Quintanar-Guerrero Laboratorio de Investigación y Posgrado en Tecnología Farmacéutica, Facultad de Estudios Superiores Cuautitlán, Universidad Nacional Autónoma de México, Cuautitlán Izcalli, Estado de México, México Abstract: A biodegradable polymeric system is proposed for formulating peptides and proteins. The systems were assembled through the adsorption of biodegradable polymeric nanoparticles onto porous, biodegradable microspheres by an adsorption/infiltration process with the use of an immersion method. The peptide drug is not involved in the manufacturing of the nanoparticles or in obtaining the microspheres; thus, contact with the organic solvent, interfaces, and shear forces required for the process are prevented during drug loading. Leuprolide acetate was used as the model peptide, and poly(D,L-lactide-co-glycolide) (PLGA) was used as the biodegradable polymer. Leuprolide was adsorbed onto different amounts of PLGA nanoparticles (25 mg/mL, 50 mg/mL, 75 mg/mL, and 100 mg/mL) in a first stage; then, these were infiltrated into porous PLGA microspheres (100 mg) by dipping the structures into a microsphere suspension. In this way, the leuprolide was adsorbed onto both surfaces (ie, nanoparticles and microspheres). Scanning electron microscopy studies revealed the formation of a nanoparticle film on the porous microsphere surface that becomes more continuous as the amount of infiltrated nanoparticles increases. The adsorption efficiency and release rate are dependent on the amount of adsorbed nanoparticles. As expected, a greater adsorption efficiency (~95%) and a slower release rate were seen (~20% of released leuprolide in 12 hours) when a larger amount of nanoparticles was adsorbed (100 mg/mL of nanoparticles). Leuprolide acetate begins to be released immediately when there are no infiltrated nanoparticles, and 90% of the peptide is released in the first 12 hours. In contrast, the systems assembled in this study released less than 44% of the loaded drug during the same period of time. The observed release profiles denoted a Fickian diffusion that fit Higuchi's model (t1/2). The manufacturing process presented here may be useful as a potential alternative for formulating injectable depots for sensitive hydrophilic drugs such as peptides and proteins, among others. Keywords: adsorption, biodegradable polymers, controlled release, nanoparticles, porous microspheres, peptide delivery

This chapter provides an overview up to date of the emulsification-solvent evaporation method to prepare polymer nanoparticles for pharmaceutical researchers and formulators. It highlights the recent technological advances, assessment, and new modalities of this method (e.g., double-emulsion and emulsification-solvent displacement). The aim of this chapter is to review representative works and discuss the raw materials, preparative variables, conditions, formation mechanisms, etc., in order to make them useful for specific developments of drug nanoparticles. The considerable progress which has been made in the Van de Hoff's method will be reviewed with examples and applications to show its effectiveness, versatility, advantages, and limitations. Finally, the chapter is written in such way that the reader obtains enough criteria involved in the process to facilitate the formulation task.

RESUMEN: La nanotecnología es una ciencia que posee grandes expectativas en diversas áreas, pues contempla la obtención de bloques de materia muy pequeños, creados a nivel molecular o atómico, para el desarrollo de nuevos dispositivos o materiales con propiedades mejoradas. Una de las aplicaciones más prometedoras de la nanotecnología es la nanomedicina, la cual involucra el desarrollo de nanosistemas diseñados para monitorear la salud, liberar fármacos, curar enfermedades o reparar tejidos. Respecto a la liberación de fármacos, ésta se ha asentado en el antiguo concepto de la “bala mágica”, en el que se establece una búsqueda de diminutas partículas o nanoacarreadores capaces de dirigir sustancias activas al sitio donde son requeridas, con el objetivo de mantener y controlar la entrega del fármaco en tiempo y espacio. La intensa investigación de las últimas tres décadas ha demostrado que los nanoacarreadores cumplen con esas expectativas y representan una mejor respuesta para atender las necesidades terapéuticas actuales.

"Ethyl cellulose polymeric nanoparticles (NPs) were prepared using the solvent-displacement technique with ethanol as the solvent. Optimization of the method included evaluating stirring rate and stabilizer type. NPs of 142.1 to 226.5 nm were obtained in a reproducible and efficient way (95% process efficiency) and with good stability (at room temperature). Moreover, a recirculation device was used in order to obtain concentrated NPs dispersions by a continuous process with potential scale-up. This method was challenged to encapsulate a hydrophilic antiviral model molecule (glycyrrhizinic acid) resulting in low entrapment efficiencies (approximately 1%). The results indicate that NPs are obtained using this simple, economical process that offers the possibility to transport different agents for applications in food-processing, cosmetics production or pharmaceutical products."

RESUMEN El propósito de este trabajo fue obtener, optimizar y caracterizar nanovesículas ultraflexibles, también conocidas como Transferosomas®, cargadas con un antihipertensivo de la familia de las dihidropiridinas llamado felodipino, para ser evaluados como sistemas de administración transdérmica. Lo anterior radica en la importancia de proponer nuevos y mejores tratamientos para enfermedades de interés, como la hipertensión arterial (HTA), donde los tratamientos convencionales han llevado a la ineficacia terapéutica debido a la alta frecuencia de administración, altas dosis y una serie de efectos no deseados para el paciente que los consume, lo que como resultado ha llevado a una disminución en el apego al tratamiento. Existen diferentes grupos de fármacos antihipertensivos, formulados en formas farmacéuticas orales, donde han destacado los bloqueadores de canales de Ca+2, grupo donde se encuentra el felodipino. Este fármaco se ha caracterizado por tener una alta potencia y selectividad; sin embargo, su baja solubilidad, alto metabolismo de primer paso y efectos adversos, minimizan su eficacia cuando se administra por vía oral. Es por lo anterior y por sus propiedades fisicoquímicas que se han buscado alternativas para su administración y formulación. Aquí se propone la vía transdérmica y el uso de nanoacarreadores como estrategia debido a las ventajas que poseen, como su capacidad de llevar el fármaco a través de la piel para alcanzar un efecto sistémico terapéutico deseado. En particular los Transferosomas®, un tipo de liposomas o nanovesículas ultraflexibles, capaces de atravesar las capas de la piel debido a su facilidad de deformación sin pérdida medible del fármaco y su capacidad de acarrear tanto fármacos lipofílicos como hidrofílicos. Para el desarrollo del proyecto se seleccionaron materiales a partir de pruebas de solubilidad y la capacidad de los fosfolípidos de generar una película. Los Transferosomas® se obtuvieron mediante el método de hidratación de película, optimizando el proceso hasta la obtención de una talla promedio objetivo con un diseño experimental 24 obtenido con el software Statgraphics. La eficiencia de 2 encapsulación del felodipino en las nanovesículas se determinó haciendo uso de 8 métodos distintos de incorporación, en donde se usaron diferentes proporciones de etanol y diferentes pHs para favorecer la entrada del fármaco al nanosistema. Una vez seleccionados los Transferosomas® considerados como óptimos, se llevó a cabo una caracterización física de estos por tamaño promedio, PDI, potencial zeta, flexibilidad, rendimiento, morfología, interacción de los materiales y estabilidad, empleando técnicas como la espectrofotometría UV, calorimetría diferencial de barrido, espectroscopía infrarroja, y microscopía electrónica de transmisión. Así mismo se evaluó su eficacia in vitro con estudios de liberación y pruebas de permeabilidad en piel de cerdo. Como resultado se obtuvieron Transferosomas® sin fármaco con talla promedio de 200 nm y PDI

RESUMEN La HTA es una condición en la que los vasos sanguíneos presentan una presión por encima del límite establecido, la cual desencadena problemas cardiovasculares y/o cerebrovasculares. De acuerdo con la OMS se estima que en el mundo hay 1130 millones de personas con hipertensión y de éstos 1 de cada 5 tiene controlado el problema (Organización Mundial de la Salud, 2019). Su tratamiento requiere de cambios en los hábitos alimenticios, la rutina diaria de ejercicio y el uso de fármacos antihipertensivos. Estos tratamientos farmacológicos logran tener un efecto terapéutico pero con ciertas desventajas: un claro ejemplo es la hidroclorotiazida (de la familia de los diuréticos tiazídicos), ya que puede causar efectos metabólicos no deseados como depleción de potasio, disminución de la tolerancia a la glucosa e impotencia; también pueden estar contraindicados con otras patologías como los bloqueadores beta adrenérgicos dentro de los cuales se encuentra el atenolol, que es eficaz contra la HTA pero debe evitarse en la enfermedad pulmonar obstructiva crónica, bloqueo cardiaco e hipotensión, además de que se debe reducir la dosis en casos de insuficiencia renal (Velasco, et al, 2002); otros tienen efectos adversos frecuentes molestos para el paciente como lo es la tos seca y persistente al usar el enalapril (de la familia de los IECA); otros podrían causar el efecto contrario al esperado como el nifedipino, de los bloqueadores de los canales de calcio, ya que si es un preparado de corta duración puede causar variaciones grandes en la presión arterial e incluso taquicardia refleja; otros requieren de dosis altas como es el caso de la metildopa, de los fármacos que actúan sobre el sistema nervioso central, ya que requiere de hasta 250 mg de fármaco 2-3 veces al día llegando a un máximo de 3 g al día (World Health Organization, 2004). Dentro de los antagonistas de los receptores de la angiotensina II (ARA II) se encuentra el telmisartán, un fármaco clase II, prácticamente insoluble en agua con alta permeabilidad (

Las vías respiratorias se encuentran revestidas por una capa de mucosa, por lo que se está investigando el desarrollar micro o nanopartículas bioadhesivas cargadas con fármacos para tratar enfermedades agudas y crónicas de los pulmones, siendo de interés aquellos fármacos que presentan baja solubilidad y menor eficacia cuando se administran por la vía oral. Estos sistemas particulados ofrecen una liberación prolongada, una mejor biodisponibilidad, disminuyen la frecuencia de dosis, los efectos secundarios y la resistencia bacteriana, para el caso de antibióticos. El polímero Gantrez® AN posee propiedades bioadhesivas, aerolizables, biodegradables y biocompatibles, por lo que es buen candidato para ser empleado como micro o nanoacarreador pulmonar de fármacos. Por otro lado, la azitromicina es un antibiótico que presenta baja solubilidad acuosa y biodisponibilidad oral; sin embargo, es administrado por esta vía para el tratamiento de enfermedades respiratorias como la neumonía. El objetivo de este proyecto fue desarrollar, caracterizar y evaluar un micronanosistema biodegradable y bioadhesivo para la administración pulmonar de azitromicina, como una alternativa para el tratamiento de la neumonía. Para producir las partículas se empleó el método de emulsión-evaporación del disolvente, donde la fase acuosa (X1, 4 y 8 mL) corresponde a una mezcla 90:10 acetona:agua, que contiene el polímero y la azitromicina previamente disueltos por separado (50, 100 y 150 mg). La fase oleosa estuvo compuesta por aceite mineral y Span® 80 (X2, al 1 y 3 % p/v) como emulsificante. Con un homogeneizador ULTRA-TURRAX® se agitó la fase oleosa, agregando por goteo la fase acuosa, manteniendo una agitación de 6000 o 12000 rpm (X3), durante 3.5 o 5 minutos (X4), en presencia o ausencia de porógeno (X5), según un Diseño Experimental. La micronanosuspensión obtenida se dejó en agitación magnética durante 24 h. Las partículas se recuperaron por centrifugación y se lavaron con cloroformo, para después ser resuspendidas en una solución acuosa de manitol al 5% (p/v), y se liofilizaron. Las partículas optimizadas se caracterizaron por tamaño promedio (Y1), potencial Z (Y2), rendimiento (Y3) y eficiencia de encapsulación (Y4), además de estudios por FTIR, Difracción de Rayos X y DSC para evaluar su estado sólido y las interacciones que pudieran presentarse. Se realizó el perfil de liberación de las partículas con PBS (pH 6.6), a 37 °C, durante 30 h, así como el modelado matemático del mismo. Se determinó la bioadhesión de los sistemas con soluciones de mucina y tejido pulmonar de cerdo. También se evaluaron las propiedades aerolizables de las micropartículas (MP’s) como formulaciones para polvo seco para inhalación y como suspensión para nebulización. Finalmente, para evaluar la eficacia antibacterial de las partículas, se usaron las cepas bacterianas: RESUMEN XI Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli y Klebsiella pneumoniae. En la ejecución del diseño experimental se obtuvieron MP’s, con tamaños de 63 a 5396 nm. Empleando el MSR se seleccionaron los niveles óptimos de los factores de estudio para obtener partículas de tamaño menor a 5 µm y con la mejor eficiencia de encapsulación, resultando óptimas aquellas con carga inicial de 100 mg de azitromicina, las cuales presentaron rendimiento de 81.01 ± 2.16%, tamaño de 1104.67 ± 81.67 nm, potencial Z de -22.50 ± 0.70 mV y eficiencia de encapsulación del 42.17 ± 8.36%. De acuerdo con lo observado en el FTIR, no hay formación de nuevos enlaces en las partículas cargadas con fármaco. La Difracción de Rayos-X evidenció que el fármaco se amorfiza al incorporarse en las partículas. Con DSC se observó que no hay interacciones significativas entre los componentes de las partículas y que el fármaco se encuentra molecularmente disperso en las MP’s. Las MP’s presentaron una liberación prolongada, alrededor del 95% del fármaco fue liberado en 24 h, con un mecanismo de liberación de transporte de super caso II, es decir, por medio de procesos de erosión e hinchamiento por parte de las MP’s. Las MP’s interactúan con las mucinas y presentaron una bioadhesión del 54.9 ± 4.5% en tejido pulmonar. Al formularse como polvo seco para inhalación, mezclando con lactosa, presentan buena aerolización y una densidad compactada menor a 0.4g/mL que sugiere que las partículas pueden ser depositadas exitosamente en el interior del pulmón. Cuando se formulan como suspensión para nebulización se obtiene un MMDA menor a 3 µm y una GSD menor a 2, lo que confirma que la distribución de tamaño es estrecha y se encuentra en un tamaño de partícula fino, características adecuadas para lograr un suministro eficiente en los pulmones. La actividad de la azitromicina no se pierde cuando se incorpora en las micropartículas, se obtuvieron CMI’s más grandes en comparación con el fármaco solo, debido al efecto de la velocidad de liberación prolongada que presentan. Se lograron desarrollar, caracterizar y evaluar micropartículas biodegradables y bioadhesivas de Gantrez® AN, encapsulando azitromicina bajo condiciones óptimas, con un tamaño adecuado para administrarse por vía pulmonar y con una eficiencia de encapsulación suficiente para administrar dosis terapéuticas del fármaco en el tratamiento de la neumonía. The airways are covered by a mucosal layer, so research is underway to develop bioadhesive micro-nanosystems loaded with drugs to treat acute and chronic lung diseases, focus on drugs with low solubility and bioavailability when are administered by oral route. These particulated systems offer prolonged release, better bioavailability, decrease in dosage frequency, less side effects and bacterial resistance in the case of antibiotics. Gantrez® AN is a polymer that has bioadhesive, aerolyzable, biodegradable and biocompatible properties, which lead it to be a good candidate to pulmonary administration as drug carrier. On the other hand, Azithromycin is an antibiotic with low aqueous solubility and oral bioavailability, however, it is administered by this route to treat respiratory diseases such as pneumonia. The aim of this project was to develop, characterize and evaluate a biodegradable and bioadhesive micro-nanosystem for the pulmonary administration of azithromycin as alternative treatment for pneumonia. The emulsion-solvent evaporation method was used to produce the particles, where the aqueous phase contains a mixture 90:10 of acetone:water (X1, 4 and 8 mL), where the polymer and Azithromycin were previously dissolved by separate (50, 100 and 150 mg). The oil phase consisted of mineral oil and Span® 80 (X2, at 1 and 3% w/v) as emulsifier. Using an ULTRA-TURRAX® the oleous phase kept on agitation at 6000 or 12000 rpm (X3), while the aqueous phase was added by dripping, during 3.5 or 5 minutes (X4), in the presence or absence of porogen (X5), according to the Experimental Design. The obtained suspension was left in magnetic agitation for 24 h in order to evaporate the solvent. The particles were recovered by centrifugation and washed with chloroform, and then resuspended in an aqueous solution of mannitol at 5% (w/v), and lyophilized. Optimized particles were characterized by average size (Y1), Z-Potential (Y2), yield (Y3), and encapsulation efficiency (Y4), besides studies by FTIR, X-Ray Diffraction and DSC to evaluate their solid state and interactions. The release profile was performed in PBS (pH 6.6) as dissolution medium, at 37 °C, during 30 h, and data were mathematically modeled. Bioadhesion studies were carried out using mucin solutions and pig lung tissue. The aerolyzable properties of microparticles were also evaluated as dry powder formulations for inhalation and aerosol suspension to nebulization. To evaluate the antimicrobial efficacy, bacterial strains were used: Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Escherichia coli y Klebsiella pneumoniae. The microparticles prepared according to the experimental design showed sizes from 63 to 539641 7 nm. Using the RSM, the optimal factor levels were predicted to obtain particles with size less than 5 µm and the best encapsulation efficiency, so that the optimal ABSTRACT XIII ones were prepared with 100 mg of azithromycin, which presented a size of 1104.67 ± 81.67 nm, a Z-potential of -22.50 ± 0.70 mV, a yield of 81.01 ± 2.16%, and encapsulation efficiency of 42.17 ± 8.36%. Based on the FTIR analysis, findings evidenced no formation of new bonds in the drug-loaded particles. The pattern obtained from X-Ray Diffraction showed that the drug was amorphized when is incorporated into the particles. It was observed no significant interactions between components, when thermograms of DSC studies were analyzed, from this it was suggested that drug is molecularly dispersed in the micro-nanospheres. The microparticles presented an extended release because 95% of the drug was released in 24 h by a transport super case II mechanism, which means that erosion and swelling processes are involved. Microparticles interact with mucins, presenting a bioadhesion of 54.9 ± 4.5% in lung tissue. When formulated as a dry powder inhalation, mixing with lactose, particles have good aerolyzation and a tapped density less than 0.4 g/mL that suggests they can be deposited inside the lung. When formulated as suspension to nebulize it was determined a MMDA less than 3 µm and a GSD less than 2, confirming the narrow size distribution and a fine particle size, characteristics suitable for an efficient delivery of particles into the lungs. Azithromycin activity is not lost when incorporated into microparticles, however, larger MIC were obtained than free drug, because of the extended release offered by the particles. It was possible to develop, characterize and evaluate biodegradable and bioadhesive microparticles of Gantrez® AN, encapsulating azithromycin under optimal conditions, with an adequate size to be administered by pulmonary route and enough encapsulation efficiency to administer a dose according to pneumonia therapy.

RESUMEN En el presente estudio se evaluó el uso e impacto de los nanoplexos de chitosán cargados con atorvastatina, con el propósito de estudiar su efecto sobre la solubilidad y la velocidad de disolución de este fármaco, ya que con una solubilidad acuosa de 20.4 μg/ml a pH 1.2 y de 1.23 mg/ml a pH 6.0, y un logP de 5.7 está clasificado como un fármaco clase II (baja solubilidad, alta permeabilidad), de acuerdo con el sistema de clasificación biofarmacéutica (SCB). La atorvastatina es un fármaco aprobado para el tratamiento de la hipercolesterolemia, el cual es un problema de salud pública que en los últimos años ha ido aumentando y es una de las principales causas de muerte a nivel nacional, debido a los problemas cardiovasculares que provoca. Un nanoplexo es una nanopartícula polimérica formada mediante la interacción electrostática entre un fármaco ionizable y un polielectrolito de carga opuesta, generalmente polímeros sintéticos o naturales iónicos o con grupos ionizables en sus monómeros. En el proyecto se realizó la optimización de los nanoplexos con base en un diseño experimental factorial 24, empleando como factores la cantidad de fármaco (15 y 30 mg), la cantidad de chitosán (6 y 150 mg), el tipo de estabilizante (Brij 58 o Pluronic F68) y la concentración de estabilizante (0.5 y 1.5 %). Ya optimizados por metodología de superficie de respuesta (MSR), los nanoplexos se prepararon disolviendo 22 mg de atorvastatina en 3 ml de metanol y 22 mg de chitosán en 30 ml de una solución de buffer de acetatos pH 5.3 y ácido acético al 1 %. Empleando el método de nanoprecipitación la solución de atorvastatina fue vertida gota a gota a la solución de chitosán, rápidamente y bajo homogenización a 15,000 rpm, durante 10 minutos. Las nanopartículas se recuperaron mediante centrifugación, posteriormente se caracterizaron determinando la talla promedio (DLS), el potencial Z (MEF), la morfología (SEM), la eficiencia de complejación (UV), la interacción de componentes (DSC, IR), la cristalinidad (XRD), la solubilidad en condiciones de saturación y el perfil de disolución in vitro a pH 1.2 y 6.8. Los resultados evidenciaron nanoplexos esféricos sólidos, con un tamaño de 431.53 ± 12.64 nm y un potencial Z de 36.3 ± 1.0 mV. La eficiencia de complejación obtenida fue de 85.29 ± 0.60 % con un rendimiento del 66 ± 1.2%. Los espectros de rayos (XRD), calorimetría diferencial de barrido (DSC) e infrarrojo (IR) indicaron que existe una interacción entre el polímero y el fármaco, y sin cambios químicos estructurales. Los perfiles [RESUMEN] 10 de junio de 2018 2 de disolución a pH 1.2 mostraron que tanto la atorvastatina libre, como la encapsulada en los nanoplexos, se disuelve aproximadamente el 90 % en 24 horas, en contraste con los perfiles a pH 6.8 donde el 100 % de fármaco libre se disuelve a los 30 minutos, mientras que el incluido en los nanoplexos se libera el 100 % en 24 horas. La solubilidad de la atorvastatina en los nanoplexos en condiciones saturadas muestra un aumento de hasta cinco veces más con respecto a la solubilidad acuosa. En conclusión, se obtuvieron nanoplexos de chitosán cargados con atorvastatina con propiedades tecnológicas para ser formulados en sistemas de liberación modificada, con un impacto positivo en la solubilidad y velocidad de disolución, los cuales pueden ser empleados en la formulación de formas farmacéuticas para diferentes vías de administración, incluida la vía parenteral, en las que habría un ajuste o reducción de la dosis y una menor frecuencia de administración. SUMMARY In the present study, the use and impact of chitosan nanoplexes loaded with atorvastatin were evaluated, with the purpose of studying its effect on the solubility and dissolution rate of atorvastatin, since it has a solubility of 20.4 μg / ml at pH 1.2 and of 1.23 mg / ml at pH 6.0, which is why it is classified as a class II drug (low solubility, high permeability) according to the biopharmaceutical classification system (SCB). Atorvastatin is an approved drug for the treatment of hypercholesterolemia, which is a public health problem that in recent years has been increasing and is one of the leading causes of death nationwide, due to the cardiovascular problems it causes. A nanoplex is a polymeric nanoparticle formed by the electrostatic interaction between an ionizable drug and a polyelectrolyte of opposite charge, generally synthetic or natural ionic polymers or with ionizable groups in their monomers. In the project, the optimization of nanoplexes was carried out using a factorial design 24, using as factors the amount of drug (30 mg, 15 mg), the amount of chitosan (6 mg, 150 mg), the type of stabilizer (Brij 58, Pluronic F68) and the stabilizer concentration (1.5%, 0.5%). Already optimized by response surface methodology (MSR), the nanoplexes already optimized, the nanoplexes were prepared by dissolving 22 mg of atorvastatin in 3 ml of methanol and 22 mg of chitosan in 30 ml of a buffer solution of acetates pH 5.3 and acid 1% acetic acid. Using the nanoprecipitation method, the atorvastatin solution was poured drop by drop into the chitosan solution, rapidly and under homogenization at 15,000 rpm for 10 minutes. The nanoparticles were recovered by centrifugation, then characterized by determining the average size (DLS), the Z potential (MEF), the morphology (SEM), the complexing efficiency (UV), the interaction of components (DSC, IR), the solubility under saturation conditions and the in vitro dissolution profile at pH 1.2 and 6.8. The results showed solid spherical nanoplexes, with a size of 431.53 ± 12.64 nm and a Z potential of 36.3 ± 1.0 mV. The efficiency of complexation obtained was 85.29 ± 0.60% with a yield of 66 ± 1.2% the spectra of rays (XRD), differential scanning calorimetry (DSC) and infrared (IR) showed that there is an interaction between the polymer and the drug, but without structural chemical changes. The dissolution profiles at pH 1.2 showed that both free atorvastatin and encapsulated in the nanoplexes dissolves approximately 90% in 24 hours in contrast to the profiles at pH 6.8 where 100% of free drug dissolves 30 minutes, while the [SUMMARY] 10 de junio de 2018 4 one included in the nanoplexes is released 100% in 24 hours. The solubility of atorvastatin in the nanoplexes under saturated conditions shows an increase of these five times more with respect to the aqueous solubility. In conclusion, chitosan nanoplexes loaded with atorvastatin with technological properties were obtained to be formulated in modified and controlled release systems, with a positive impact in the reduction of the dose and frequency of administration of atorvastatin.