Liposome Determatics to Come According to the Patent Literature

Abstract

After the first production of liposomes in 1961, it took more than two decades until the first commercial liposome preparation of a drug for topical use was made available. This was a liposome gel with econazole as an active ingredient. This particular medicament, marketed as Pevaryl®-Lipogel by the Cilag Corporation in Switzerland, meant a major breakthrough in the developement of topical liposome drugs in so far as it demonstrated by principle that physical and chemical instability are not necessarily a major obstacle to the practical use of this type of drug carrier on a large scale. Unfortunately, its clinical superiority over a conventional preparation has not yet been investigated so far. At least Hänel et al. [1] have recently demonstrated a greater efficacy of the 1% econazole gel preparation as compared to a 2% conventional ketoconazole preparation in a guinea-pig tinea model. From a theoretical standpoint, an azole and even antimycotics in general cannot be looked upon as prime candidates for liposome encapsulation as the existant conventional forms to be used topically with these active principles are fairly safe and efficacious; the latter is not too astonishing as the fungi are located in the uppermost parts of the skin.