Does needle clogging change the spatial distribution of injected drug in tissue? New insights by X-ray computed tomography.

Prefilled syringes (PFS) are primary packaging materials that offer convenience and safety for subcutaneous injection of parenteral drug solutions. However, an increasingly common problem with the trend towards higher drug concentrations is the clogging of the needle during storage due to evaporative water loss and consequent solidification of the drug. In contrast to all previous studies on this topic, this work focuses on pharmacokinetically relevant aspects and investigates the effects of needle clogging on the spatial distribution of the injected drug in the tissue.

Needle clogging of protein solutions in prefilled syringes: A two-stage process with various determinants.

Clogging of staked-in-needle prefilled syringes (PFS) is a sporadic and scarcely predictable event, which occurs particularly in highly concentrated protein solutions and can result in the injection of incomplete doses, especially if autoinjector devices are used for administration. A systematic screening of possible causes and triggers was performed in order to find the crucial factors of influence, the underlying mechanisms and possible measures for prevention. An essential prerequisite for the formation of a solidified clog in the needle is the ingress of liquid from the barrel, which was investigated and quantified by means of neutron imaging after storage of prefilled syringes under various conditions.