Appeal No. 2005-0126
Application No. 09/967,791
Keep states that highly lipid soluble drugs cross the blood brain barrier easily. Column
4, lines 49-50. Keep acknowledges that “mechanisms for opening the blood brain
barrier are known and include administration of hypertonic solutions intra-arterially &
intravenously...” Column 4, lines 50-52. Naito also acknowledges these known
methods for opening the blood brain barrier, and in addition finds that ingestion (enteral
administration) of pure sugars in combination with amino acids can open the blood brain
barrier. Thus, while drugs to be delivered to other parts of the body may be
administered by a variety of known routes of administration, the brain may be unique in
this respect, due to the relative impenetrability of the blood brain barrier.
The state of the art would thus appear to indicate that the ability of compounds to
cross the blood-brain barrier is dependent upon a number of variables, including the
nature of the chemical or compounds administered, and arguably, the prior art
recognizes only limited modes of administration of the hypertonic sugar composition.
While we believe it can be concluded from the prior art that administration of a
hypertonic sugar composition enterally, intra-arterially or intravenously is effective in
disruption of the blood brain barrier, we do not agree with either the examiner or our
colleague that the examiner has presented argument based on evidence of record
which would support the position that one of ordinary skill in the art would necessarily
conclude that all modes of administration of a hypertonic sugar composition which
eventually reach the blood stream, result in a sufficient opening of the blood brain
barrier for a sufficient amount of time to allow other therapeutic compounds to cross.
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