Appeal No. 1999-0610 Page 13
Application No. 08/601,186
as to prevent or minimize the coagulation of blood (column 1,
lines 11-22). Eury achieves such a surface by incorporating
into the surface a substance that releases an anticoagulant
(heparin) for an extended period of time (column 1, lines 41-
45). In one embodiment of the invention, Eury coats the
biomedical device with a heparin-containing coating.
The coating is produced by first forming an ionic complex
(HPTC) of heparin and phosphatidylcholine (PTC, commonly
referred to as lecithin) by combining lecithin dissolved in
ethyl acetate with heparin dissolved in water in a
lecithin/heparin ratio of approximately 4.17:1. The mixture
is stirred, evaporated to dryness, subsequently dissolved in
methylchloride and added to the polymer polycaprolactone (or
poly L-lactic acid film) to form an HPTC/polymer combination
having a final heparin concentration of approximately 5% (or
7.5%) by weight.
The examiner's position is that it would have been
obvious to one of ordinary skill in the art at the time of
appellants' invention to coat the Castillo catheter with the
antithrombogenic heparin coating taught by Eury to prevent or
minimize the coagulation of blood. Further, the examiner
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