On Wednesday, Ranbaxy Laboratories said that it would not be able to introduce a generic variant of a urinary medicine in the US as per schedule, as there has not been a final approval from the regulator yet.

India's largest drug manufacturer, based on sales, was expected to release a cheaper, copy version of Astellas Pharma's Flomax across the United States during this month, and analysts were expecting it to substantially boost sales and earnings for the company in the near future.

"We regret that despite our best efforts we were not able to get an approval for the subject product, and hence will not be in a position to launch the product", Ranbaxy said in a statement.

No reasons have been shared as to why the drug was not approved.

On Tuesday, on the other hand, Impax Laboratories Inc. announced that it had managed to gain approval from the US Food and Drug Administration for generic Flomax.