Structural and morphological aspects of (fluoro) quinolone delivery by layered double hydroxide nanoparticles

Layered double hydroxides (LDHs) have been proposed as delivery systems (DSs) of (fluoro)quinolones (QLNs) to overcome their low bioavailability and to prevent the emergence of resistant bacteria. Both LDH-DS synthesis as nanoparticles (NPs) and QLN interactions with the metal ions that constitute the layers are essential to improve their physicochemical, biopharmaceutical and antimicrobial properties. Here, LDH-DSs containing the basic form of nalidixic acid (Nal), used as a probe, were obtained by coprecipitation at variable and constant pH (LDH-Nal-pHvar and LDH-Nal-pHcte, respectively). For both syntheses, LDH NPs containing Nal anions (LDH-Nal-NPs), with sizes between 30 and 40 nm, were obtained. A coordination compound (Mg(Nal)2·4H2O, Mg(Nal)2) was also concurrent for LDH-Nal-pHcte, which modulated the drug release profile and antimicrobial properties of the LDH-Nal-NPs. Thus, Nal release from LDH-Nal-pHvar was produced mainly by anion exchange. The best fits, obtained for the Higuchi model, showed rate constants dependent on the exchanging anions (kH = 0.88 and 1.53 for NaCl 0.9% and buffer phosphate 0.05 M, pH = 7.4, respectively). The nanometric size of LDH-Nal-pHvar as well as its faster release rate allowed a minimum inhibitory concentration decrease (MIC = 32 μg mL−1) compared to the pure drug (MIC = 128 μg mL−1). Instead, the presence of Mg(Nal)2 in LDH-Nal-pHcte led to a more sustained and media independent Nal release, but a lower MIC (64 μg mL−1) than LDH-Nal-pHvar.Fil: Salguero Salas, Yadira Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: García, Mónica Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; ArgentinaFil: Mosconi, Giuliana. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; ArgentinaFil: Rojas Delgado, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentin

Ciprofloxacin-intercalated layered double hydroxide-in-hybrid films as composite dressings for controlled antimicrobial topical delivery

Films based on biopolymers and loaded with antimicrobial agents are convenient pharmaceutical dosage forms for topical application. Inorganic carriers loaded with these agents lead to composite materials, which combined with polymers produce further functionality. Here, hybrid composite films based on layered double hydroxide (LDH) and hyaluronan (HS) as ciprofloxacin (Cip) delivery systems were studied as an alternative for prophylaxis and treatment of opportunistic infections in wounds. Cip-intercalated Zn-Al LDH (LDH-Cip), with high drug loading and crystallinity, were obtained by a precipitation at variable pH method, and then included in a HS dispersion for obtaining the hybrid composite films by solvent casting. Physicochemical characterization of films showed that a composite material where the HS acted as matrix and LDH-Cip aggregates acted as filler were obtained. LDH-Cip were uniformly dispersed along the (LDH-Cip)/HS films, which exhibited roughness in their surface, increasing their swelling capacity in PBS pH = 5.8. Controlled releases of Cip toward PBS at pH = 5.8 and 7.4 were obtained, and the best fits for the release profiles were found with Higuchi and Korsmeyer-Peppas models, respectively. (LDH-Cip)/HS films exhibited antimicrobial activity against S. aureus. These films would then provide sustained release of Cip after topical administration, maintaining a suitable level of antibacterial activity, combined with the wound healing properties of the HS. The interesting properties shown by the (LDH-Cip)/HS films make them a promising alternative for application in skin wounds.Fil: Salguero Salas, Yadira Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Escuela Politécnica Nacional; EcuadorFil: Valenti, Laura Elisa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Rojas Delgado, Ricardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: García, Mónica Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Unidad de Investigación y Desarrollo en Tecnología Farmacéutica; Argentin