Inspire Pharmaceuticals Inc., which is the target of a Merck & Co. acquisition bid, said Tuesday its first-quarter loss widened, partly because of a $12.2 million restructuring charge.

The Raleigh, N.C., company lost $17.6 million, or 21 cents per share, in the three months that ended March 31. That compares with a loss of $14.8 million, or 18 cents per share, in the same quarter last year. Revenue fell 4 percent to $21.1 million.

Analysts surveyed by FactSet expected, on average, earnings of 22 cents per share on $20.4 million in revenue.

The maker of the pink-eye treatment Azasite said its operating expenses climbed 6 percent in the quarter to $38.8 million, mainly due to charges tied to its corporate restructuring and the discontinuation of its pulmonary therapeutic operations. But research and development and general and administrative expenses fell.

In January, Inspire said it would cut 65 jobs, or 27 percent of its work force, and concentrate on eye-care drugs after the failure of an experimental cystic fibrosis treatment. Revenue from Azasite, which treats pink eye cause by bacteria, climbed 26 percent to $10.9 million.

Merck, based in Whitehouse Station, N.J., said last month it will buy Inspire for about $430 million, or $5 per share. That represented a 26 percent premium to Inspire's closing price before the deal was announced.

Inspire's board recommended shareholders tender their shares in the deal. Warburg Pincus Private Equity IX L.P., which owns about 28 percent of Inspire's stock, backs the deal.