Hong Kong : Global buyout firm Advent International and U.S. based Baxter International are among suitors preparing to submit separate bids to buy unlisted Indian drugmaker Gland Pharma Ltd, three people with direct knowledge of the matter told Reuters.

Gland Pharma founders and KKR & Co, who jointly own about 96 percent of the company, are selling their combined stake, which is valued at between $1 billion and $1.5 billion, the people said.

Indian drugmaker Torrent Pharmaceuticals is the other company set to place binding bids due by middle of next month, said the people, who declined to be identified, as the deal talks are confidential.

Gland Pharma, based in the southern Indian city of Hyderabad, develops and manufactures generic injectables, primarily to sell in the United States and India.

Advent, KKR and Baxter declined to comment. Officials at Gland and Torrent did not respond to Reuters' request for comment.