CINCINNATI—Touting it as its most challenging hair-care product to date, Procter & Gamble announced Monday a new complicated 1-in-2 version of its Pantene shampoo. “Our new Pro-V 1-in-2 line gives women the shiny, luxurious hair of the original Pantene but with a superfluous extra step added to the process,” spokeswoman Tiffany Piette said of the Pro-V 50-50 shampoo, which comes packaged in two separate tubes of solvent and glycol meant to be mixed together in a precise 5-to-3 ratio along with warm water. “Its added complexity allows you to get luxurious, salon-quality looks while also forcing you to spend an extra two minutes in the shower.” Piette added that an even more difficult-to-use conditioner was in the works, consisting of two bottles that would never be sold at the same store.