Process In Body And Safety Of A Novel Pegylated Insulim

ObjectiveAt present pegylation is the hotspot technology in secondary development of protein drugs. This project study on process in body and safety of pegylated insulin(PEG-Det) to explain the rationality and scientificity of long effective mechanism and safety of pegylation.MethodIn this study, based on characteristic of biotech drugs, two bioanalytical methods, radioimmunoassay (RIA) and enzyme linked immunosorbent assay (ELISA) were established and employed to investigate the effect of pegylation on process in body and safety of insulin. The studies performed are listed as follows:①Pharmacokinetics and pharmacodynamics of PEG-Det in Beagle dogs comparison with that of non-pegylated insulin (Det);②Toxicokinetics and dynamicsof PEG-Det;③Immunogenicity and Immunotoxicity of PEG-Det following repeated subcutaneous administration to Beagle dogs;④Safety evaluation of the pegylated Det insulin for injection.Results(1) Process in body results shows:①The pegylated protein exhibited preferred pharmacokinetic properties to Det in Beagle dogs, with a59-fold increase in elimination half life, and a35-fold decrease in serum clearance (CL), as well as a9-fold increase in the time to reach peak serum concentration (Tmax) respectively.②After PEG-Det were injected once subcutaneously to Beagle dogs at a doses of25,50, and100μg/kg, respectively, a greater than proportional increase in Cmax, AUC and Tmax for PEG-Det was observed with the increasing doses, while the rate of clearance decreased with increasing doses. Tmp was found to be dose-independent.③Following repeated subcutaneous administration of PEG-Det at a dose of50μg/kg to Beagle dogs, no accumulation of the drug was found in body.④When the dogs were exposed to PEG-Det at the toxic doses of37.5,75, and150μg/kg respectively, the plasma drug concentrations varied in an oppsite direction to the blood glucose levels, that was to say, an increase in plasma drug concentrations was definitely accompanied by a decrease in blood glucose level, and vice versa. The blood glucose level returned to its baseline value at the twelve hours after the administration of PEG-Det. Both Cmax and AUC increased with the increase of dose and no accumulation in body was observed.(2) Safety results shows:①The anti-PEG-Det antibody was specific to the PEG moiety, which had nothing to do with Det itself.②PEG-Det has no significant effect on the level of C3, C4, CIC, leukocyte counts and differential counts, and has no significant toxicity on immune tissues and organs.③Following subcutaneous and intravenous administration of PEG-Det, no irritation effects was found on the skin, muscle and blood vessel at the injection sites.④The negative results of active systemic allergy test in guinea pigs and of passive allergy test in rats indicated that PEG-Det may not introduce allergic reactions in humans.⑤The results of hemolysis test in vitro was also encouraging.ConclusionThese findings demonstrate that compared to unmodified Det, pegylation of Det possesses more desirable pharmacokinetic and pharmacodynamic properties, including prolonged biological half-life, decreased system clearance, enhanced drug exposure, reduced serum peak-to-trough con-centration ratio,increased safety and increased efficacy.