The speculation follows a research note from Sanford C Bernstein in which analyst Tim Anderson suggested that Pfizer may divest the businesses, along with its animal health and nutritionals units.
Anderson, who cited a meeting with Pfizer CEO Ian Read in his research, told the Wall Street Journal that the divestitures may start taking place in the next year to 18 months.
The five named units generate around 40 per cent of Pfizer’s $67bn a-year revenue with the generic or ‘established products’ division contributing $10bn a year at present.
If they take place, the divestitures would leave Pfizer with just four remaining divisions focused on: primary care; speciality care; oncology and emerging markets.
Pfizer, which has not commented on the speculation, began a strategic review of its operations in October that initially focused on its dosage form manufacturing business Capsugel.
The capsules unit, which generated $732m in 2010, was seen as having the strongest potential for growth due, according to Cavan Redmond, senior vice president & group president, Pfizer's Diversified Businesses, to the breadth of its technology portfolio.
Capsugel’s portfolio was further strengthened by the acquisition of GlaxoSmithKline’s (GSK) Flextab capsule filling business a few weeks ago.
More recently the US drugamker’s strategic review has expanded beyond Capsugel.
In February, Read said Pfizer is looking at “the composition of our business portfolio to determine the optimal mix of businesses that we can appropriately fund and manage in order to achieve consistent growth and maximum return on investment.”