RESUMEN

Iron deficiency anemia (IDA) presents a global health challenge, impacting crucial development stages in humans and other mammals. Pigs, having physiological and metabolic similarities with humans, are a valuable model for studying and preventing anemia. Commonly, a commercial iron dextran formulation (CIDF) with iron dextran particles (IDPs) is intramuscularly administered for IDA prevention in pigs, yet its rapid metabolism limits preventive efficacy. This study aimed to develop and evaluate chitosan thermosensitive hydrogels (CTHs) as a novel parenteral iron supplementation strategy, promoting IDPs' prolonged release and mitigating their rapid metabolism. These CTHs, loaded with IDPs (0.1, 0.2, and 0.4 g of theoretical iron/g of chitosan), were characterized for IM iron supplementation. Exhibiting thermosensitivity, these formulations facilitated IM injection at ~4 °C, and its significant increasing viscosity at 25-37 °C physically entrapped the IDPs within the chitosan's hydrophobic gel without chemical bonding. In vitro studies showed CIDF released all the iron in 6 h, while CTH0.4 had a 40% release in 72 h, mainly through Fickian diffusion. The controlled release of CTHs was attributed to the physical entrapment of IDPs within the CTHs' gel, which acts as a diffusion barrier. CTHs would be an effective hydrogel prototype for prolonged-release parenteral iron supplementation.

RESUMEN

The objective of this study was to develop a novel subgingival sustained-release system for local delivery of bioactive minocycline hydrochloride for periodontal disease treatment in dogs. The system incorporated the Minocycline hydrochloride-Calcium-Dextran sulfate sodium into a thermoresponsive Pluronic F127 hydrogel. Minocycline hydrochloride was sustained release from the system for up to 10 days and the release kinetics fit the power law model. The release medium had a significant statistical difference in antimicrobial activity to Aggregatibacter actinomycetemcomitans. The results showed the system was a promising subgingival sustained-release minocycline hydrochloride delivery system for periodontal disease treatment in dogs.

O objetivo deste estudo foi desenvolver um novo sistema subgengival de liberação sustentada para administração local de cloridrato bioativo de minociclina para tratamento da doença periodontal em cães. O sistema incorporou o cloridrato de minociclina-cálcio-dextrano sulfato de sódio em um hidrogel Pluronic F127 termorresponsivo. O cloridrato de minociclina foi liberado do sistema por até 10 dias e a cinética de liberação se ajustou ao modelo da lei de potência. O meio de liberação apresentou uma diferença estatística significativa na atividade antimicrobiana para Aggregatibacter actinomycetemcomitans. Os resultados mostraram que o sistema foi um promissor sistema subgengival de liberação sustentada de cloridrato de minociclina para o tratamento da doença periodontal em cães.

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RESUMEN

The development of thermosensitive bioadhesive hydrogels as multifunctional platforms for the controlled delivery of microbicides is a valuable contribution for the in situ treatment of vagina infections. In this work, novel semi-interpenetrating network (s-IPN) hydrogels were prepared by the entrapment of linear poly(methyl vinyl ether-alt-maleic anhydride) (PVME-MA) chains within crosslinked 3D structures of poly(N-isopropylacrylamide) (PNIPAAm). The multifunctional platforms were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermal techniques, rheological analysis, swelling kinetic measurements, and bioadhesion tests on porcine skin. The hydrogels exhibited an interconnected porous structure with defined boundaries. An elastic, solid-like behavior was predominant in all formulations. The swelling kinetics were strongly dependent on temperature (25 °C and 37 °C) and pH (7.4 and 4.5) conditions. The s-IPN with the highest content of PVME-MA displayed a significantly higher detachment force (0.413 ± 0.014 N) than the rest of the systems. The metronidazole loading in the s-IPN improved its bioadhesiveness. In vitro experiments showed a sustained release of the antibiotic molecules from the s-IPN up to 48 h (94%) in a medium simulating vaginal fluid, at 37 °C. The thermosensitive and bioadhesive PNIPAAm/PVME-MA systems showed a promising performance for the controlled release of metronidazole in the vaginal environment.

RESUMEN

A novel thermosensitive hydrogel consisting of phosphorylated ß-cyclodextrin (ßCD-PH), ß-cyclodextrin (ßCD) and chitosan was prepared by embedding ßCD and ßCD-PH, into the well-studied chitosan/αß-glycerophosphate system (CS/αßGP). The relevance of this work is the use of ßCD-PH to partially substitute αßGP as the gelling agent. The role of ßCD and ßCD-PH on the rheological properties of hydrogels, gelation time, and gelation temperature were investigated. The gelation time for all the samples (CS/αßGP, CS/αßGP/ßCD, and CS/αßGP/ßCD-PH) was less than a minute at 37 °C, which is suitable for biomedical applications. The gelation temperature for hydrogel CS/αßGP/ßCD-PH increased linearly with the addition of ßCD-PH within the interval 31.8-37.3 °C, at ratios CS:ßCD-PH of 1:0.5, 1:1, 1:1.5 and 1:2 (w/w). The hydrogel thus obtained has potential applications in dual drug delivery (hydrophilic and hydrophobic).