Physico-chemical stability of co-formulation of PEGylated human amylin with insulin.

Since the discovery of amylin no combined formulation with insulin has been made available. Amylin or its triple proline analog pramlintide are not compatible in solution with insulin. The drug candidate hAmy-PEG5k is a novel monoPEGylated amylin derivative with improved physicochemical properties and retained similar pharmacological activity compared to free amylin and pramlintide. We have investigated the short- and long-term physicochemical compatibility of hAmy-PEG5k co-formulated with slow-acting human insulin analogs glargine or detemir. While human amylin promptly aggregates over a large range of pH, and both free and in the presence of regular, glargine or detemir insulin, the hAmy-PEG5k analog is stable at these conditions as shown by Thioflavin T (ThT) binding assay. When hAmy-PEG5k (100 or 500 µg/mL) was added to the commercial formulations of either insulin glargine or detemir (95 IU/mL), the combinations remained stable after 6 months stored at 4 °C, as probed by ThT, dynamic light scattering (DLS) measurements and high performance liquid chromatography (HPLC) analyses, confirming the absence of amyloid fibers, minor aggregation products or loss of material. These results suggest hAmy-PEG5k and the insulin analogs glargine and detemir are physicochemically compatible and are candidate ready-to-use fixed-dose combinations.

IL-13 immunotoxin accelerates resolution of lung pathological changes triggered by silica particles in mice.

Instillation of silica into the lungs of rodents results in pathological changes that strongly mimic human silicosis, an occupational lung disease marked by restrictive airway obstruction, inflammation, and fibrosis. Because IL-13 is a pivotal proinflammatory and fibrogenic cytokine, we examined whether a recombinant immunotoxin comprised of human IL-13 and a mutated form of Pseudomonas exotoxin (IL-13-PE) might affect pathological features of experimental silicosis. Mice received a single intranasal instillation of silica particles and were treated with intranasal IL-13-PE every other day from days 21 to 27 postsilica. The sensitivity of putative cell targets to IL-13-PE was also assessed in in vitro settings. Upregulation of IL-13, its receptor subunits IL-13Rα1 and IL-13Rα2, and shared receptor IL-4Rα were associated with development of granulomatous lung inflammation triggered by silica. IL-13-PE inhibited silica-induced granuloma and fibrotic responses noted at 24 h and 15 d after the last treatment. Upregulation of TNF-α, TGF-ß, and chemokines, as well as increased collagen deposition and airway hyperreactivity to methacholine were all clearly sensitive to IL-13-PE. In addition, IL-13-PE inhibited both IL-13-induced proliferation of cultured lung fibroblasts from silicotic mice and silica-induced IL-8 generation from A549 cells. In conclusion, our findings show that therapeutic treatment with IL-13-PE can reverse important pathological features caused by inhalation of silica particles, suggesting that this recombinant immunotoxin is a promising molecular template in drug discovery for the treatment of silicosis.