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.

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Nanocapsules (NCs) are submicron-sized core shell systems which present important advantages such as improvement of drug efficacy and bioavailability, prevention of drug degradation, and provision of controlled-release delivery. The available methods for NC production require expensive recovery and purification steps which compromised the morphology of NCs. Industrial applications of NCs have been avoided due to the aforementioned issues. In this study, we developed a new method based on a modified self-microemulsifying drug delivery system (SMEDDS) for in situ NCs production within the gastrointestinal tract. This new methodology does not require purification and recovery steps and can preserve the morphology and the functionality of NCs. The in situ formed NCs of Eudragit RL PO were compared with nanospheres (NEs) in order to obtain evidence of their core-shell structure. NCs presented a spherical morphology with a size of 126.2 ± 13.1 nm, an ibuprofen encapsulation efficiency of 31.3% and a zeta-potential of 37.4 mV. Additionally, NC density and release profile (zero order) showed physical evidence of the feasibility of NCs in situ creation.

Abstract. Different carriers were obtained employing the emulsification-diffusion method in order to compare the release profile of a nonsteroidal anti-inflammatory drug from nanocapsules and nanospheres elaborated with Eudragit®. All the batches presented a submicronic particle size, good stability (ζ >30 mV) and the density test confirmed the nanocapsule and nanosphere structure. Evaluation of the release kinetics of ibuprofen using the Korsmeyer-Peppas model evidenced values for the “n” coefficient of 0.799 and 0.816 for nanocapsules and nanospheres, respectively. This indicates that both systems adhere an anomalous diffusion release mechanism that combines drug diffusion and erosion of the polymer.   Resumen. Se obtuvieron diferentes acarreadores mediante el método de emulsificación-difusión con el objetivo de comparar el perfil de liberación de un antiinflamatorio no esteroideo (ibuprofeno) en nanocápsulas y nanoesferas elaboradas con Eudragit®.  Todos los lotes obtenidos presentaron un tamaño de partícula submicrónico, adecuada estabilidad (ζ >30 mV) y las pruebas de densidad permitieron confirmar la estructura de los sistemas preparados. La evaluación de la cinética de liberación de ibuprofeno utilizando el modelo de Korsmeyer-Peppas proporcionó coeficientes “n” de 0.799 y 0.816 para nanocápsulas y nanoesferas, respectivamente. Estos valores indican que ambos sistemas presentan un mecanismo de liberación anómalo, que combina los fenómenos de difusión del fármaco y erosión del polímero.

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