(Reuters) - Valeant Pharmaceuticals International Inc's (>> Valeant Pharmaceuticals Intl Inc) sales are expected to rise 15 percent in the third quarter but will face a tougher fourth-quarter comparison to year-ago results, Allergan Inc (>> Allergan, Inc.) said in a filing on Monday.

Allergan, the maker of Botox anti-wrinkle injections, has criticized Valeant's acquisition-based business model as it attempts to fend off the drugmaker's $51 billion hostile bid.

Valeant's third-quarter sales will reflect a weak year-ago period for contact lens maker Bausch & Lomb, which Valeant acquired for $8.7 billion in August 2013, according to the filing.

The Canadian company did not give a specific fourth-quarter forecast but said last week that it expects continued strong double-digit same store organic growth in the fourth quarter. Valeant announced that it will report third-quarter earnings on Oct. 20.

(Reporting by Susan Kelly in Chicago; Editing by Lisa Shumaker)

Stocks treated in this article : Allergan, Inc., Valeant Pharmaceuticals Intl Inc