In vitro anti-tuberculosis effect of chitosan-gelatin/poly(lactic acid co-glycolic acid) combined with drug-loaded hydrogel / 中国组织工程研究

BACKGROUND: Anti-tuberculous chemotherapy is the main method for treating bone and joint tuberculosis. However, systemic administration hardly maintains the effective drug concentration in the focus area, and the therapeutic efficacy is unsatisfactory. OBJECTIVE: To prepare a chitosan-gelatin/poly(lactic-co-glycolic acid) combined with drug-loaded hydrogel, which can release anti-tuberculosis drugs in situ for a long time and promote osteogenesis. METHODS: Isoniazid, a hydrophilic anti-tuberculosis drug, and a hydrophobic stromal cell derived factor-1 were loaded into poly(lactic-co-glycolic acid) by double emulsion method to prepare drug-loaded poly(lactic acid co-glycolic acid) microspheres, which were then mixed into chitosan gelatin/poly(lactic acid co-glycolic acid) combined with drug-loaded hydrogel. The ability of drug delivery and anti-tuberculosis of poly(lactic acid co-glycolic acid) microspheres and chitosan gelatin/poly(lactic acid co-glycolic acid) combined with drug-loaded hydrogels in vitro were tested. MC3T3-E1 cells were inoculated on the surface of microspheres and hydrogel respectively. The biocompatibility was detected by cell counting kit-8 assay. The osteogenetic activity was detected by alkaline phosphatase activity. RESULTS AND CONCLUSION: (1) The burst release of isoniazid in the microspheres was about 23.3% in 1 hour, 42.6% in 2 days, and then it entered the sustained-release stage in the later 25 days. The burst release of stromal cell derived factor was about 19.8% in 1 hour, 44.7% in 2 days, and then it entered the sustained-release stage in the next 25 days. The release of isoniazid and stromal cell-derived factor in the combined drug-loaded hydrogel was 8.3% and 8.5% in the first hour, respectively. The cumulative release rates on the second day were 15.2% and 17.6%, respectively, which were much lower than that of poly(lactic acid co-glycolic acid) microspheres. (2) After 4 weeks in vitro, the antibacterial diameter of the combined drug-loaded hydrogel was much larger than that of the drug-loaded microspheres, and the antibacterial rate was higher than that of the drug-loaded microspheres (P < 0.05). (3) The combined drug-loaded hydrogel and the drug-loaded microspheres had good cytocompatibility and cell viability was about 100%. (4) After 5 and 10 days of culture, there was no significant difference in the activity of alkaline phosphatase on the surface of drug-loaded hydrogel and drug-loaded microspheres. (5) These results show that the in situ chitosan-gelatin/poly(lactic acid co-glycolic acid) combined with drug-loaded hydrogel can be used for treating tuberculosis and other bone and joint infections.

Design and preparation of a novel colon-targeted tablet of hydrocortisone

ABSTRACT The objective of this research was to design a new colon-targeted drug delivery system based on chitosan. The properties of the films were studied to obtain useful information about the possible applications of composite films. The composite films were used in a bilayer system to investigate their feasibility as coating materials. Tensile strength, swelling degree, solubility, biodegradation degree, Fourier transform infrared spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), Scanning electron microscope (SEM) investigations showed that the composite film was formed when chitosan and gelatin were jointly reacted jointly. The results showed that a 6:4 blend ratio was the optimal chitosan/gelatin blend ratio. In vitro drug release results indicated that the Eudragit- and chitosan/gelatin-bilayer coating system prevented drug release in simulated intestinal fluid (SIF) and simulated gastric fluid (SGF). However, the drug release from a bilayer-coated tablet in SCF increased over time, and the drug was almost completely released after 24 h. Overall, colon-targeted drug delivery was achieved by using a chitosan/gelatin complex film and a multilayer coating system.

RESUMO O objetivo desta pesquisa foi planejar um novo sistema de liberação de fármacos direcionado ao cólon, utilizando quitosana. Estudaram-se as propriedades dos filmes a fim de obter informações úteis sobre a aplicação desses filmes compósitos. Utilizaram-se os filmes compósitos em sistema de bicamada para investigar a sua viabilidade como materiais de revestimento. Estudos de resistência à tração, grau de intumescimento, solubilidade, grau de biodegradação, no infravermelho por transformada de Fourier (FTIR), de calorimetria diferencial de varredura (DSC) e de microscopia eletrônica de varredura (SEM) mostraram que o filme compósito se formou quando a quitosana e a gelatina reagiram entre si. Os resultados mostraram que a mistura de proporção ótima foi de 6:4 de quitosana:gelatina. Resultados da liberação do fármaco in vitro indicaram que o sistema de revestimento de Eudragit e bicamada de quitosana/gelatina impediu a liberação de fármaco em fluido intestinal simulado (SIF) e em fluido gástrico simulado (SGF). Entretanto, a liberação de fármaco do comprimido revestido em bicamada no SCF aumentou ao longo do tempo e o fármaco foi quase completamente liberado após 24 h. Em geral, se obteve a forma de liberação dirigida ao cólon, utilizando filme complexo de quitosana/gelatina e sistema de revestimento multicamada.

Preparation and evaluation of gentamicin loaded chitosangelatin composite films for wound healing activity.

Natural polymers are used as lead compounds for design of therapeutic drug delivery systems for treatment of different ailments. Chitosan and gelatin have proven wound healing properties individually. As both have wound healing property, the combination of these two polymers and incorporation of drugs into the composite films may show improvement in wound healing property. Thus, the composite films and drug loaded films were evaluated for various in vitro evaluation tests and to ascertain the applicability of prepared combination for wound healing activity. The composite films were prepared with increase in gelatin concentration. The drug loaded films were prepared with increasing concentrations of drug. These films were evaluated for thickness, folding endurance, water absorption capacity, antibacterial activity, tensile strength, in vitro drug release by diffusion studies and in vivo studies by excision wound model. The drug loaded films shown significant difference in folding endurance, water absorption capacity, antibacterial activity when compared to optimized composite film. There was no significant difference in thickness and tensile strength of drug loaded films when compared to blank composite films. Percentage of wound contraction was more for wounds treated with gentamicin loaded chitosan-gelatin composite film than blank composite film. With the above results, gentamicin loaded chitosan-gelatin combination had shown better results when compared to chitosan-gelatin film, chitosan film alone in wound healing activity.