MONTREAL — Paladin Labs Inc. will take over all commercial responsibilities for the selling, marketing and distribution of Estring estrogen product in Canada under a revised agreement with Pfizer Canada Inc. The Montreal-based pharmaceutical company said Thursday the terms of its existing agreement with Pfizer will be amended upon the the close of Pfizer Inc.'s US$68-billion acquisition of Wyeth. Financial terms of the Estring agreement weren't disclosed. Antitrust regulators in Canada and the United States cleared Pfizer's purchase of Wyeth, subject to certain conditions. The companies will divest certain animal pharmaceutical and vaccine products, including Wyeth's vaccines for cattle, dogs, and cats, and medicines used in treating cattle, dogs, cats, and horses., to Boehringer Ingelheim Vetmedica Inc. The Wyeth takeover was expected to close Thursday. Estring is an intravaginal ring that provides sustained local release of estrogen over a three-month period. It used to treat post-menopausal urogenital complaints.