Elder Pharmaceuticals' shares tumbled 8.17 per cent to close the day at Rs 298.30 on the BSE. In intra-day, the scrip slipped 11.42 per cent to Rs 287.75.
At the NSE, the scrip nosedived by 8.74 per cent to settle at Rs 296.70.
Similar weakness was seen at Torrent Pharmaceuticals Ltd counter, where the stock dropped by 4.04 per cent to Rs 479.50.
"Torrent Pharmaceuticals has entered into a definitive binding agreement with Elder Pharmaceuticals to acquire its branded domestic formulations business in India and Nepal for a consideration of Rs 2,000 crore," Torrent Pharmaceuticals Ltd said in a filing with the BSE.
Elder's India business comprises a portfolio of 30 brands, including some market leading ones in women healthcare, pain management, wound care and neutraceuticals.
Torrent would fund the acquisition through a mix of internal accruals and bank borrowings, the company said.
The transaction has been approved by the boards of both the companies and is subject to approval by shareholders and other necessary regulatory nods. The deal is expected to close in the first half of 2014.