Iroko Pharmaceuticals L.L.C. laid off about a fourth of its staff, a company official said Tuesday.

About three dozen people were laid off on Sept. 13 from the company's headquarters in the Philadelphia Navy Yard, according to reports.

Osagie Imasogie, chairman of the Iroko's board, said that while headquarters and administrative staff were cut, the company would be adding as many as 90 sales representatives.

The company makes and markets Vivlodex, Tivorbex, Zorvolex and Indocin, all non-opioid pain medicines known as nonsteroidal anti-inflammatory drugs. 

The layoffs come at a time when generic drugs are pushing aside branded products in the marketplace.

A company official said that sales by quantity are up, but that Iroko has had to sell its products at a lower price.