[Adsorption of insulin to the Perfusor systems]

Using radioimmunoassay determination we examined the recovery rate of 100 units of regular insulin that had been added to 50 ml. of a carrier solution in a plastic Perfusor syringe. We measured the recovery rate with sodium chloride 0.9% as carrier and after adding albumin (10 g./l.) and gelatine (6 g./l. resp. 12 g./l.). An initial insulin loss of 26% (with albumin) to 37% (with gelatine) was followed by only a small loss (less than 9%) during the next 24 hours. We conclude from our results that it is unnecessary to add substances with high molecular weight in order to reduce insulin adsorption to Perfusor systems.