Appeal No. 2003-1020 Page 4
Application No. 08/859,051
Mezei describes the relative activities of two different preparations of
triamcinolone: 0.1% triamcinolone in “ointment dosage form,” and a liposomal
preparation of 0.1% triamcinolone free of unencapsulated triamcinolone. According to
Mezei, “liposomal encapsulation favorably altered [triamcinolone] deposition; the
greatest changes occurred in the target tissue, and at the sites where toxic actions are
localized.” “[P]ercutaneous absorption was greatly reduced, while at the same time, the
concentration of the drug was significantly increased at the site (i.e., epidermis and
dermis), where its activity is desired” (page 1474). Thus, “the presently accepted
therapeutic concentration can be achieved by a four-fold reduction in the dose . . .
[which] would lead to . . . an additional decrease in unwanted systemic effects” (pages
1475-1476).
du Plessis teaches that “the deposition of [a topically administered liposome-
encapsulated] drug into the living epidermis and/or dermis cannot be predicted by
determination of the amount of drug in the total skin” as “[t]he amounts in the deeper
skin strata were also in the order of increasing number of follicles/hair in the skin
species, suggesting that the transfollicular route is an important pathway for liposomal
topical therapeutics” (Abstract, page 259). That is, “liposomal drug transport into strata
below and beyond the stratum corneum may occur via a follicular route” (page 263).2
According to the examiner, “[i]t is unclear from . . . Bonte and Rössling whether
the unencapsulated active agent was removed,” but “[o]ne skilled in the art would be
motivated to remove the [un]encapsulated material if it is detrimental since [ ] Mezei
teaches that [un]encapsulated material can be removed by chromatography” and “[o]ne
2 The stratum corneum is the outer layer of the epidermis, consisting of several
layers of flat keratinized non-nucleated cells. Stedman’s Medical Dictionary, Illustrated,
24th Edition, Williams & Wilkins, Baltimore/London, page 1347 (1982).
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