(Table 2) Anticoagulant release profile with and without controlled release feature

In vitro determination of heparin release was carried out
using partial devices built to allow visualization of the flow path. Blood
release from the skin was simulated using a syringe pump-controlled flow
system. Water was introduced to test devices at either 25 or 50 µL/min.
Aliquots of the rinse liquid were recovered from the reservoir side of the
devices throughout the collection. The concentration of heparin in the aliquots
was then measured using a colorimetric assay based on the metachromasia of
Azure A.