Pfizer on Monday defended its plan to buy AstraZeneca following a slate of criticism surrounding the proposed deal. The pharmaceutical company also questioned AstraZeneca's ability to stand alone for much longer as the group's Chief Executive Pascal Soriot faced a grilling from MPs over the plan.US-based Pfizer said its agreement to complete AstraZeneca's new research centre in Cambridge, keep a factory in northwest England and put a fifth of its research staff in Britain were legally binding if the deal is sealed. The proposed $106bn deal would mark the largest foreign takeover of a British firm.However, the deal has been opposed by many scientists and politicians who have raised doubts over Pfizer's commitment to UK jobs. Critics are also worried about protecting the British company's research. "If you keep your sense of curiosity and an open mind, you can learn tremendously," Pfizer's Research and Development Head Mikael Dolsten said in a video posted on Pfizer's website. "We must stay laser-focused on our important projects. And that's, of course, true for Pfizer scientists and AZ scientists and will be true also if we can make a potential combination come together."British lawmakers will on Tuesday question Pfizer's Scottish-born Chief Executive Ian Read about the acquisition plans.RD