RESUMEN
Nanoscopic vehicles that stably encapsulate drug molecules and release them in response to a specific trigger are of great interest due to implications in therapeutic applications, especially for cancer therapy. For this purpose, we have synthesized highly stable polymeric nanogels, in which the kinetics of guest molecule release can be fine-tuned by control over cross-linking density. The polymer nanogel precursor is based on a random copolymer that contains oligoethyleneglycol (OEG) and pyridyldisulfide (PDS) units as side-chain functionalities. By introducing variations into the precursor polymer, such as molecular weight and the relative percentages of hydrophilic OEG units and hydrophobic PDS functionalities, we have achieved significant control over nanogel size. We show that the noncovalently encapsulated guest molecules can be released in response to a redox trigger, glutathione (GSH). Stability of dye encapsulation inside the nanogels and tunability in the release of guest molecules have been demonstrated through in vitro fluorescence resonance energy transfer (FRET) experiments. We show in vitro doxorubicin delivery into breast cancer cells (MCF-7) with nanogels of different cross-linking density to demonstrate that it plays a key role in the stable encapsulation of hydrophobic drug molecules and the cell-uptake efficiencies.
Asunto(s)
Portadores de Fármacos/química , Polietilenglicoles/química , Polietileneimina/química , Cápsulas , Disulfuros/química , Doxorrubicina/metabolismo , Diseño de Fármacos , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Espacio Intracelular/metabolismo , Cinética , Células MCF-7 , Nanogeles , Polietilenglicoles/síntesis química , Polietileneimina/síntesis químicaRESUMEN
OBJECTIVES: To study the correlation of obesity with various metabolic parameters and correlation between insulin resistance and leptin and retinol binding protein 4 (RBP4) levels. METHODS: This is a cross sectional study in a tertiary care children's hospital wherein 98 obese children were included and their metabolic parameters analysed with regards to insulin resistance and RBP4 levels. RESULTS: Leptin levels were abnormal for all children and high RBP4 levels were observed in 69.6 %. There was no significant association between insulin resistance and RBP4 levels (p 0.8). CONCLUSIONS: RBP4, the sole retinol transporter in blood, secreted from adipocytes and liver has been implicated in insulin resistance. The index study however, did not show a significant positive association.