It’s a germo-phobic fashionista’s dream. Prada’s new skin-care line features single-use-size vials, packets, and tubes, each hermetically sealed (with argon gas, no less) in its own pouch. The Italian fashion house, famous for sleek minimalist fashion and $600 backpacks, launches the high-concept line this month. Items like lip balm and toner go for around $60 for a 30-day supply. But why the sample-size packaging? ”Cellular phones are lighter and easier to carry than most personal-care products,” argues a Prada spokesperson. Adds Deborah Walters of Saks Fifth Avenue, which will carry the line, ”It’s extremely suited for travel.” Now jet-setting socialites can cram more makeup into those pricey Prada backpacks.