Zaleplon is indicated for the short-term treatment of insomia. Zaleplon capsules are generic equivalent of Kings Pharmaceuticals' Sonata capsules.
Unichem received the approval immediately on expiry of the patent on Zaleplon. The company intends to launch the product in US market shortly, it said.
The company's share at the BSE closed at Rs 147, up 4.33 per cent from the previous day.