Allergan (NYSE: AGN) has entered into a definitive agreement to purchase the "topical aesthetics" skin care business of privately held SkinMedica. The business in question, which does not include SkinMedica's Colorescience line of make-ups, focuses on sales of prescription and non-prescription skin care products generally sold by doctors.

Allergan describes the acquisition as complementary to its existing product lines, the most famous of which is probably Botox. It also has Juvederm and Latisse. Allergan will pay SkinMedica $350 million immediately, with an additional $25 million to be paid if the business hits certain sales targets.

While privately held SkinMedica does not break down its financial information publicly by product line, annual sales of the company as a whole are estimated to be in the range of $69 million.