Gladys Ester Granero

Based on the demonstrated and reported trypanocidal, leishmanicidal, and antiplasmodial activities of two menthol prodrugs, it was decided to proceed with preformulation studies, which are of key relevance in the drug discovery process. The aim of this study is to examine the stability and permeability of two new menthol prodrugs with antiparasitic activity. To determine the stability of menthol and its prodrugs, the corresponding studies were carried out in buffered solutions at pH values of 1.2, 5.8, and 7.4 at 37 °C. In silico permeability studies were performed using the free PerMM software and then in vitro permeability studies were performed using a biomimetic artificial membrane (BAM). Permeability studies conducted in silico predicted that both menthol and its prodrugs would pass through biological membranes via flip-flop movement. This prediction was subsequently confirmed by in vitro BAM permeability studies, where it was observed that the menthol prodrugs (1c and 1g) exhi...

Introduction: Cyclodextrins (CD), are known to form inclusion complexes with a variety of guest molecules both in solution and in the solid state. This can lead to the alteration of properties of guest molecules. Unfortunately, the complexation efficiency of CD is rather low, and can be enhanced by formation of ternary complexes using aminoacids (AA). Sulfadiazine (SDZ) is an antibiotic with extremely low water solubility which limits its therapeutic applications and bioavailability. Objetives: The aim of this work was to increase the aqueous solubility of SDZ by preparing ternary complexes of this drug with β-cyclodextrin (βCD) and an AA as a third auxiliary substance. Materials y Methods: Complex formation was studied by phase solubility analysis (PSA), nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), thermogravimetric analysis (TG) and scanning electron microscopy (SEM). Results: The apparent stability constants (KC) of the multicomponent complexes were ...

Layered double hydroxides (LDHs) are inorganic solids composed of cationic layers and inter-lamellar spaces filled with negative ions. In the last years, LDHs have gained interest as carriers of anionic drugs, which replace the interlayers ions. Most anti-tumor drugs are systemically administered and this produces many side effects. LDHs could protect and target them to the tumor; however, most anti-tumor drugs have no charge and thus, they are not able to enter into the interlamellar space. Aiming to overcome this problem, a surfactant was used in this work. Carbamazepine (CBZ), an anticonvulsant drug with a formal charge of 0, has shown efficacy against some solid cancer cell lines; it also produces alterations in red blood cells. Here, this drug was used as a model drug to be load into the system. CBZ was incorporated into HDLs, composed of Mg2-Al-NO3, in micelles of sodium cholate (a surfactant with negative charge) by using different methods: ionic exchange, coprecipitation and reconstruction. Different amounts of surfactant were assessed, at a critical micelle concentration. X-ray powder diffractograms showed that the drug incorporated in the system when synthesized by ionic exchange and reconstruction, but not by co-precipitation. The hydrodynamic sizes of the HDLs loaded with the drug in the micelles were measured by dynamic light scattering. The amount of CBZ loaded in the system was determined by UV and found to be ~2 %, which represents almost 100 % of the original amount of drug. Assays of drug released were done in Franz Cells with a Simulated Body Fluid (pH 7.4) and an acetate buffer (pH 4.8) in order to analyze the protector role of the system in the blood and the drug release inside the tumor cells respectively. Results suggest that LDHs are promising drug delivery carriers by allowing the incorporation of all kinds of drugs and not only of that with anionic charge.Fil: Peralta, Maria Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; ArgentinaFil: Scolari, Ivana Romina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Granero, Gladys Ester. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacia; ArgentinaFil: Crivello, Mónica Elsie. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; ArgentinaFil: Mendieta, Silvia Nazaret. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigación y Tecnología Química. Universidad Tecnológica Nacional. Facultad Regional Córdoba. Centro de Investigación y Tecnología Química; ArgentinaReunión anual de Sociedades de Biociencia 2019Mar del PlataArgentinaSociedad Argentina de Investigación ClínicaSociedad Argentina de ProtozoologíaAsociación Argentina de Farmacología ExperimentalSociedad Argentina de BiologíaAsociación Argentina de Ciencia y Tecnología de Animales de LaboratorioHistochemical SocietyAsociación Argentina de Nanomedicina

Nanotechnology is a very promising technological tool to combat health problems associated with the loss of effectiveness of currently used antibiotics. Previously, we developed a formulation consisting of a chitosan and tween 80-decorated alginate nanocarrier that encapsulates rifampicin and the antioxidant ascorbic acid (RIF/ASC), intended for the treatment of respiratory intracellular infections. Here, we investigated the effects of RIF/ASC-loaded NPs on the respiratory mucus and the pulmonary surfactant. In addition, we evaluated their cytotoxicity for lung cells in vitro, and their biodistribution on rat lungs in vivo after their intratracheal administration. Findings herein demonstrated that RIF/ASC-loaded NPs display a favorable lung biocompatibility profile and a uniform distribution throughout lung lobules. RIF/ASC-loaded NPs were mainly uptaken by lung macrophages, their primary target. In summary, findings show that our novel designed RIF/ASC NPs could be a suitable system for antibiotic lung administration with promising perspectives for the treatment of pulmonary intracellular infections.

In this work, three pH values (8, 9 and 10) were studied for the insertion of Indomethacin (Indo) molecules into Layered Double Hydroxides (LDHs). The obtained results showed that the LDH materials have been a good storage for the drug. LDHs provide thermal stability with an increase in the thermal decomposition of the drug around 100°C more. Indo into LDHs exhibited higher photostability to UV light irradiation. In vitro drug release experiments in a phosphate buffer solution (pH = 7.4) have been carried out. The loading amount of intercalated Indo was increased to 66 % at pH 8, and showed a profile of sustained release of 97 % in 8h. The release profiles were fitted by mathematical models, which describe various kinetic models that served to investigate the drug release mechanism, being the Bhaskar kinetics model the most appropriate. The results showed that the nanohybrids can be used as an effective drug delivery system.

Carbamazepine (CBZ) was incorporated into layered double hydroxides (LDH) to be used as a controlled drug system in solid tumors. CBZ has a formal charge of zero, so its incorporation in the anionic clay implies a challenge. Aiming to overcome this problem, CBZ was loaded into LDH with sodium cholate (SC), a surfactant with negative charge and, for comparison, without SC by the reconstruction method. Surprisingly, it was found that both resultant nanocomposites had similar CBZ encapsulation efficiency, around 75%, and the LDH-CBZ system without SC showed a better performance in relation to the release kinetics of CBZ in simulated body fluid (pH 7.4) and acetate buffer simulating the cellular cytoplasm (pH 4.8) than the system with SC. The CBZ dimensions were measured with Chem3D and, according to the basal spacing obtained from X-ray patterns, it can be arranged in the LDH-CBZ system as a monolayer with the long axis parallel to the LDH layers. Fourier transform infrared spectroscop...

Biopharmaceutics classification systems based on the properties of solubility and permeability or the extension of metabolism are very important tools in the early stages of the development and regulatory stages of new products. However, until now, there was no clear understanding between the interplay among these classification systems. Therefore, the main objective of this work was to make a comparison of concepts of BCS and BDDCS to understand what are the key factors that allow for the integration of these biopharmaceutics classification systems. Also, the suitability of an in situ single-pass intestinal perfusion assay in rats (SPIP) development was assessed by us to determine the limit between high and low permeability following what the FDA BCS guidance suggests. An excellent correlation was found between the values of permeability obtained by applying SPIP assays and the extensions of the metabolism of the set of compounds studied in this work, with the exception of three co...

This work aimed to design and characterize cross-linked hyaluronic acid-itaconic acid films loaded with acetazolamide-hydroxypropyl β cyclodextrin-triethanolamine complexes. Films were cross-linked with itaconic acid and poly(ethyleneglycol)-diglycidylether. Biopharmaceutical properties were assessed by evaluating in vitro drug release rate, biocompatibility in a human corneal epithelial cell line, bioadhesiveness with pig gastric mucin, in vivo bioadhesion and efficacy. Showed good mechanical properties and oxygen permeability. Proliferation rate of corneal cells was affected by highest acetazolamide concentration. Bioadhesive interaction exhibited a water movement from pig mucin to the film; in vivo experiments showed strong bioadhesion for 8 h and hypotensive effect for almost 20 h. Experimental set showed promising performance and encouraged future studies to optimize formulation. [Formula: see text].

This work is focused on the synthesis of polycaprolactone nanoparticles, coated with chitosan, in a confined impinging jets reactor using the solvent displacement method. The role of the various reacting species was investigated, evidencing that a biocompatible polymer, e.g. polycaprolactone, is required to support chitosan to obtain a mono-modal particle size distribution, with low particle diameters. A surfactant is required to reduce nanoparticles size (down to a mean diameter of about 260 nm) and obtain a positive Zeta potential (about +31 mV), perfectly suitable for pharmaceutical applications. Different surfactants were tested, and Poloxamer 388 appeared to be preferable to polyvinyl alcohol. The effect of the concentration of Poloxamer 388 (in the range 0.5-5 mg ml-1) and of chitosan (in the range 1.5-5 mg ml-1) on both the mean particle size and on the Zeta potential was also investigated, evidencing that chitosan concentration has the strongest effect on both parameters. Fi...

Here, a novel drug delivery system was developed for the hydrochlorothiazide (HCT):β-cyclodextrin (βCD) inclusion complex loaded into chitosan (CS) nanoparticles (NPs) [CS/HCT:βCD NPs]. It was found, for the first time, that exposure of the intestinal mucosa to free HCT resulted in an increased and abnormal intestinal permeability associated with several injuries to the intestinal epithelium. Nevertheless, the HCT delivery system obtained ameliorated the damage of the intestinal epithelium induced by HCT. Furthermore, we found that the corresponding permeability profiles for both the free HCT and the CS/HCT:βCD NPs were exponential and lineal, respectively. We propose that the increased intestinal uptake and severe tissue injury of HCT to the intestinal epithelium could be directly related to possible effects of this drug on the ionoregulatory Na+/K+-ATPase channel. Thus, it is postulated that the CS/HCT:βCD NPs may increase the gastrointestinal retention of the HCT, which would provide increased adherence to the mucus barrier that lines the intestinal epithelium; consequently, this would act as a slow HCT release delivery system and maintain lower drug levels of luminal gut in comparison with the administration of free HCT, leading to less severe local injury.

Large oral doses of ACZ lower the intraocular pressure (IOP), but usually lead to a multitude of systemic side effects, including gastrointestinal upset. The present study was undertaken to evaluate the effect of ACZ on the histological structure of rat duodenal mucosa and to assess a possible protective role of the complex formation of ACZ with HP-β-CD, either separately or in combination with a third compound, on the gut epithelial layer by histological and ultrastructural examinations of sections of rat duodenum exposed to ACZ or its formulations. In addition, the transport process of ACZ and its binary or ternary complexes across the duodenal mucosa by means of the single-pass intestinal perfusion (SPIP) method in rats was evaluated. Evidence was found that ACZ alters intestinal permeability and induces damage to the rat small intestine. In contrast, ACZ-induced intestinal injury may be abrogated by ACZ complexation. In addition, the complexation of ACZ with HP-β-CD, alone or in...

Hydrochlorothiazide (HCT) is one of the most commonly prescribed antihypertensive drugs. In an attempt to gain an insight into the physicochemical and molecular aspects controlling the complex architecture of native β-cyclodextrin (β-CD) with HCT, we performed multiple-temperature-pH isothermal titration calorimetric measurements of the HCT:β-CD system, together with proton nuclear magnetic resonance spectroscopy ((1)H NMR), phase solubility analysis, and molecular modeling methods. The A(L)-type diagrams, obtained at different pH values and temperatures, suggested the formation of soluble 1:1 inclusion complexes of β-CD with HCT. The corresponding stability constants (K(1:1)) were determined by phase solubility studies and compared with those obtained by ITC, with good agreement between these two techniques being found. The three-dimensional array of the complex was studied by (1)H NMR and molecular modeling methods. Both techniques confirmed the formation of the inclusion complex, with good agreement between the experimental and theoretical techniques regarding the HCT binding mode to β-CD. Also, the forces involved in the association process were determined, both from the thermodynamic parameters obtained by ITC (association enthalpy, binding constant, Gibbs free energy, and entropy) and from energetic decomposition analyses derived from computational methods. We concluded that the formation of the HCT:β-CD complex was enthalpy driven, with the inclusion mode of HCT being highly dependent on its ionization state. In all cases, sustained hydrogen bond interactions with hydroxyl groups of β-CD were identified, with the solvation energy limiting the affinity. Regarding the pH and temperature dependence, lower affinity constants were found at higher HCT ionization states and temperatures.

Here, we describe the chemical characterization of the inclusion complex between diclofenac (DCF) and methyl-β-cyclodextrin (M-β-CD) in the presence or absence of monoethanolamine (MEA). Several techniques were used to analyze the complex both in solution and in the solid state. Solubility of DCF was increased by the addition of M-β-CD. However, the DCF solubility increase was more significant by the addition of M-β-CD in the presence of MEA. In vitro permeation experiments through excised human skin revealed that DCF was enhanced by M-β-CD. Nevertheless, further improvement in the flux and the permeability coefficient of DCF was obtained by the ternary system DCF-M-ß-CD-MEA.

The oxidative stress generation in bacteria by the presence of antibiotics (in this case silver nanoparticles (AgNPs)) is already widely known. Previously, we demonstrated that AgNPs generate oxidative stress in Staphylococcus aureus and Escherichia coli mediated by the increase of reactive oxygen species (ROS). In this work we are demonstrating the consequences of the oxidative stress by the presence of AgNPs; these bacterial strains increased the levels of oxidized proteins and lipids. In addition, it was possible to determine which reactive oxygen species are mainly responsible for the oxidative damage to macromolecules. Also, we found that the bacterial DNA was fragmented and the membrane potential was modified. This increase in the levels of ROS found in both, S. aureus and E. coli, was associated with the oxidation of different types of important macromolecules for the normal functioning of cell, so the oxidative stress would be one of the mechanisms by which the AgNPs would e...

The purpose of the present study was to investigate the interaction between both hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and PVP-K30 with 2-hydroxy-N-(3-methyl-5-ethyl-4-isoxazolyl)-1,4-naphthoquinone-4-imina (I), a synthetic derivative of isoxazolylnaphthoquinones that has demonstrated to exhibit important biological activity against S. aureus and T. cruzi. The continuous variation plot for I-HP-beta-CD system showed a 1:1 stoichiometry for the complex. Ultraviolet absorption spectroscopy indicates that the isoxazole moiety of I is preferably incorporated in the cavity. Furthermore, proton nuclear magnetic resonance spectroscopy suggests that this incorporation is made from the primary hydroxyl group side of the cyclodextrin. The validation of this incorporation is further evidenced by thermal analysis (DSC and TGA) and infrared spectroscopy. I-PVP-K30 interactions in solid state were demonstrated by combining the infrared spectroscopy data with the results of thermal analysis (DSC, TGA). These methods suggest that drug-polymer interaction probably occurs via intermolecular hydrogen bonding between the drug hydroxyl and polymer carbonyl groups.

The aim of our work was to develop a multicomponent inclusion complex of acetazolamide (ACZ) in order to investigate the combined effect of hydroxypropyl-β-cyclodextrin (HP-β-CD) and triethanolamine (TEA) on the solubility of ACZ and its possibility of ophthalmic delivery. Phase solubility study was used to evaluate the complexation in solution at 25°C. Complex formation was also evaluated by comparing the infrared (FT-IR) spectra of the solid complexes with a simple physical mixture containing the same amount of ACZ. FT-IR experiments provided data indicating that the carbonamido group of ACZ is involved in the inclusion process. In vitro release data showed that both formulations, containing the freeze-dried ternary complex and the corresponding simple physical mixture of ACZ with HP-β-CD and TEA presented the fastest release rate of ACZ. These results suggest that the ACZ–HP-β-CD–TEA complex represents an effective novel formulation to enhance ACZ solubility in water, turning it promising for ophthalmic administration.

The therapeutic effects of Argentine propolis ear drop formulation on canine otitis externa were evaluated. Forty-eight dogs with symptoms of otitis externa were randomly assigned to double-blinded, controlled clinical trial to evaluate the efficacy of topical formulation with propolis versus a topical placebo in the treatment of otitis externa. The propolis preparation and placebo were administrated into both external ear canals, twice daily for 14 days. Throughout the study, clinical examination and microbiological analysis of dogs ear exudates were made. The most frequent microorganisms isolated in culture media were: Malassezia pachydermatis (54.2%), Staphylococcus aureus (43.8%), coagulase-negative Staphylococcus (25.0%), Pseudomonas aeruginosa (20.8%), Candida albicans (18.8%), Proteus mirabilis (16.7%), Streptococcus spp. (16.7%), Enteroccocus faecalis (12.5%), Escherichia coli (12.5%), Staphylococcus intermedius (6.3%), Klebsiella spp. (4.2%), andCandida glabrata (2.1%). Whe...