AstraZeneca would like to comment on the correspondence from Dr. Amagasa.

As pointed out in the article, the cause of the original failure is effectively down to poor assembly of the Prefilled INOVAN syringe. A key way to avoid this issue is for the users to always refer to the assembly instructions provided by the manufacturer. AstraZeneca provides clear and easy to follow assembly instructions on the 1% Diprivan Prefilled syringe exterior carton and interior tear-off lid on assembling the plunger rod to the rubber piston before use.

AstraZeneca also points out that the design of the thick wall impacting on the operation of the 1% Diprivan Prefilled syringe is not a real concern. This is because the stopper/glass contact area, similar to any syringe design, is in the form of ribs, which will allow for a small size variation within the design tolerances. On top of this, the siliconization of our components lubricates the device in use, ensuring correct drug delivery.

The correspondence not only discusses the benefit of redesigning the plunger and stoppers on similar prefilled syringe products to what would effectively be a single piece but also comments that this might create a different suite of issues. AstraZeneca would agree with this latter point and comment that such a redesign would significantly reduce the viability of marketing such prefilled syringes, with the loss of the advantages in drug delivery these devices add to medical practice.

AstraZeneca Pharmaceuticals, Alderley Park, Cheshire, United Kingdom.