GlaxoSmithKline is on the verge of putting in a bid in excess of $15 billion for Pfizer's over-the-counter business, according to reports circulating in the media. Final bids are due on June 6, with Johnson & Johnson and Reckitt Benckiser also believed to be vying to get their hands on the $3.9 billion a year unit.

In February, Pfizer finally confirmed that it was 'exploring strategic alternatives' for the Pfizer Consumer Healthcare unit, including retaining the business, selling it or spinning it out as an independent company. Its product range includes Listerine mouthwash and Benadryl for colds and allergies.

According to Reuters, J&J and Reckitt represent the principal competition for GSK, with Novartis believed to have dropped out of the race and Bayer still mulling its position. Last year, Reckitt paid £1.9 billion (£3.5 billion) to buy Boots Healthcare, reportedly beating GSK and Bayer to the altar, and the previous year Bayer bought Roche's over-the-counter business for 2.4 billion euros ($3.1 billion).

GSK already has a healthy consumer healthcare business, with sales up 6% to £768 million for the first quarter of the year. However, while it saw strong growth in Europe (+7%) and international markets (+10%), sales in North America were down 2% - a figure that has perhaps helped drive its keen bid for Pfizer's business as it seeks to strengthen its position in this crucial market. If it is successful in snapping up Pfizer Consumer Healthcare, GSK will become the world's number one operator in this burgeoning market.