MUMBAI - Pfizer Inc, the world's top drug maker, and French firm Sanofi-Aventis are in the race to buy a stake in Indian Wockhardt Ltd's biotechnology business, the Economic Times reported on Friday.

The newspaper said both the foreign companies were doing due dligence, citing an unnamed source involved in the matter.

This would be more in the nature of a strategic business tie-up instead of a complete sell out, it quoted the source as saying.

The biotechnology business of Wockhardt could be worth 2.5 billion rupees ($48 million) according to analysts, the paper said.

Wockhardt, a mid-sized drug maker, needs about $100 million to repay debt it raised through foreign bonds that expire in September, the paper said.

Wockhardt officials could not be immediately reached for comment.

Pfizer and Sanofi told the paper they would not comment on market speculation. ($1 = 51.7 rupees) (Reporting by Bharghavi Nagaraju)