Appeal No. 2006-2213 Page 3
Application No. 09/771,151
Thus, for example, when a supersaturated solution of a drug is prepared by
heating the solution to increase drug solubility, the temperature can be lowered once
the supersaturated solution is entrapped within a liposome preparation. Id. If the
liposomes are of the correct size, the drug will not precipitate, even at a temperature
that would not normally support a supersaturated solution. Id. To ascertain whether the
drug within the liposome has precipitated, one may use spectroscopic techniques or
visual methods such as microscopy. Id. The specification discloses that liposome sizes
preferred for maintaining supersaturated solutions range from about 70-500 nm, with
liposomes of about 60-1,000 nm being “suitable.” Id.
Discussion
1. Claim construction
Claims 1, 3-9, and 16 are pending and stand rejected.
Appellants’ argument focuses entirely on whether the prior art describes
elements within claims 1 and 16, the appealed independent claims.1 We will therefore
focus on claims 1 and 16, which read as follows:
1. A method for preparing Iiposomes having an entrapped compound in
the form of a supersaturated solution, comprising:
selecting a compound having room temperature water solubility capable of
exhibiting at least a two-fold increase in response to a condition selected from
the group consisting of: (i) increasing solvent temperature, (ii) adding a co-
solvent, and (iii) changing solvent pH;
preparing from a supersaturated solution of the compound Iiposomes at
selected size intervals;
analyzing said Iiposomes for the presence or absence of precipitated
1 Page 2 of the Brief inadvertently lists claim 1 as the only independent claim. (“Sole independent claim 1
describes . . . .”). However, claim 16 is also independent.
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