Browsing by Autor "Villegas, Mercedes"

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An appraisal of the scientific current situation and new perspectives in the treatment of cutaneous leishmaniasis.
(2021) Briones Nieva, C A; Cid, Alicia Graciela; Romero, Analía Irma; García-Bustos, María Fernanda; Villegas, Mercedes; Bermúdez, José María
Leishmaniasis is a Neglected Tropical Diseases caused by protozoan parasites of the genus Leishmania. It is a major health problem in many tropical and subtropical regions of the world and can produce three different clinical manifestations, among which cutaneous leishmaniasis has a higher incidence in the world than the other clinical forms. There are no recognized and reliable means of chemoprophylaxis or vaccination against infections with different forms of leishmaniasis. In addition, chemotherapy, unfortunately, remains, in many respects, unsatisfactory. Therefore, there is a continuing and urgent need for new therapies against leishmaniasis that are safe and effective in inducing a long-term cure. This review summarizes the latest advances in currently available treatments and improvements in the development of drug administration. In addition, an analysis of the in vivo assays was performed and the challenges facing promising strategies to treat CL are discussed. The treatment of leishmaniasis will most likely evolve into an approach that uses multiple therapies simultaneously to reduce the possibility of developing drug resistance. There is a continuous effort to discover new drugs to improve the treatment of leishmaniasis, but this is mainly at the level of individual researchers. Undoubtedly, more funding is needed in this area, as well as greater participation of the pharmaceutical industry to focus efforts on the development of chemotherapeutic agents and vaccines for this and other neglected tropical diseases.
Films based on the biopolymer poly(3-hydroxybutyrate) as platforms for the controlled release of dexamethasone.
(2019) Villegas, Mercedes; Cid, Alicia Graciela; Briones, Cintia Alejandra; Romero, Analía Irma; Pistán, Florencia Alejandra; Gonzo, Elio Emilio; Gottifredi, Juan Carlos; Bermúdez, José María
Controlled drug delivery aims to achieve an effective drug concentration in the action site for a desired period of time, while minimizing side effects. In this contribution, biodegradable poly(3-hydroxybutyrate) films were evaluated as a reservoir platform for dexamethasone controlled release. These systems were morphological and physicochemically characterized. In vitro release assays were performed for five different percentages of drug in the films and data were fitted by a mathematical model developed and validated by our research group. When the profiles were normalized, a single curve properly fitted all the experimental data. Using this unique curve, the dissolution efficiency (DE), the time to release a given amount of drug (tX% ), and the mean dissolution time were calculated. Furthermore, the dissolution rate, the initial dissolution rate (a%) and the intrinsic dissolution rate were determined. The a% mean value was 1.968 × 10-2% released/min, t80% was about 14 days, and the DE was 59.6% at 14 days and 66.5% at 20 days. After 2 days, when approximately 40% of the drug was released, the dissolution rate decreased about 60% respect to the initial value. The poly(3-hydroxybutyrate) platforms behaved as an appropriate system to release and control the dexamethasone delivery, suggesting that they could be an alternative to improve drug therapy.
Modeling and evaluation of ivermectin release kinetics from 3D-printed tablets.
(2024) Briones Nieva, Cintia Alejandra; Real, Juan Pablo; Campos, Santiago Nicolás; Romero, Analía Irma; Villegas, Mercedes; Gonzo, Elio Emilio; Bermúdez, José María; Palma, Santiago Daniel; Cid, Alicia Graciela
Aim: This study focused on evaluating the influence of geometric dimensions on the drug release kinetics of 3D-printed tablets.Materials & methods: An ink based on Gelucire 50/13 was prepared to print ivermectin-loaded tablets. The ink was characterized physicochemically and tablet dissolution tests were carried out.Results: The results confirmed the suitability of the ink for 3D printing at a temperature >46°C. Changes in the crystallinity of ivermectin were observed without chemical interactions with the polymer. 3D printed tablets with varied proportional sizes showed dual behavior in their release profiles, while tablets with only thickness reduction exhibited zero-order kinetics.Conclusion: These findings highlight the versatility of 3D printing to create systems with specific and customized release profiles.
Modeling of Progesterone Release from Poly(3-Hydroxybutyrate) (PHB) Membranes.
(2016) Romero, Analia I; Bermudez, José M; Villegas, Mercedes; Dib Ashur, María F; Parentis, Mónica L; Gonzo, Elio E
Poly(3-hydroxybutyrate) (PHB) biodegradable polymeric membranes were evaluated as platform for progesterone (Prg)-controlled release. In the design of new drug delivery systems, it is important to understand the mass transport mechanism involved, as well as predict the process kinetics. Drug release experiments were conducted and the experimental results were evaluated using engineering approaches that were extrapolated to the pharmaceutical field by our research group. Membranes were loaded with different Prg concentrations and characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). SEM images showed that membranes have a dense structure before and after the progesterone addition. DSC and FTIR allowed determining the influence of the therapeutic agent in the membrane properties. The in vitro experiments were performed using two different techniques: (A) returning the sample to the receptor solution (constant volume of the delivery medium) and (B) extracting total volume of the receptor solution. In this work, we present a simple and accurate "lumped" second-order kinetic model. This lumped model considers the different mass transport steps involved in drug release systems. The model fits very well the experimental data using any of the two experimental procedures, in the range 0 ≤ t ≤ ∞ or 0 ≤ M t ≤ M ∞. The drug release analysis using our proposed approaches is relevant for establishing in vitro-in vivo correlations in future tests in animals.
Validation of kinetic modeling of progesterone release from polymeric membranes.
(2018) Romero, Analia Irma; Villegas, Mercedes; Cid, Alicia Graciela; Parentis, Mónica Liliana; Gonzo, Elio Emilio; Bermúdez, José María
Mathematical modeling in drug release systems is fundamental in development and optimization of these systems, since it allows to predict drug release rates and to elucidate the physical transport mechanisms involved. In this paper we validate a novel mathematical model that describes progesterone (Prg) controlled release from poly-3-hydroxybutyric acid (PHB) membranes. A statistical analysis was conducted to compare the fitting of our model with six different models and the Akaike information criterion (AIC) was used to find the equation with best-fit. A simple relation between mass and drug released rate was found, which allows predicting the effect of Prg loads on the release behavior. Our proposed model was the one with minimum AIC value, and therefore it was the one that statistically fitted better the experimental data obtained for all the Prg loads tested. Furthermore, the initial release rate was calculated and therefore, the interface mass transfer coefficient estimated and the equilibrium distribution constant of Prg between the PHB and the release medium was also determined. The results lead us to conclude that our proposed model is the one which best fits the experimental data and can be successfully used to describe Prg drug release in PHB membranes.