The private equity firm has been working with JPMorgan Chase & Co (>> JPMorgan Chase & Co.) and Evercore Partners Inc (>> Evercore Partners Inc.) to find a buyer for the Montreal-based drugmaker in a sale process that has been under way for several months, said the sources, who asked not to be named because the matter is confidential.

A number of potential buyers thought TPG's asking price of more than $3 billion was high and decided not to bid; it remains unclear if there will be a deal, two of the sources said.

Indian drugmaker Sun Pharmaceutical Industries Ltd (>> Sun Pharmaceutical Industries Limited) and Raleigh, North Carolina-based Salix Pharmaceuticals (>> Salix Pharmaceuticals, Ltd.) are among the companies that took a look but are no longer pursuing a deal, the two sources said.

Elan Corp (>> Elan Corporation, plc) and Forest Laboratories (>> Forest Laboratories, Inc.) also considered bidding for Aptalis earlier this year before bowing out for different reasons, a third person familiar with the matter said.

Elan was the subject of a hostile bid by Royalty Pharma and in July agreed to sell itself to U.S. drugmaker Perrigo Co (>> Perrigo Company) for $8.6 billion. Forest announced in May that its long-time chief executive would retire at the end of the year.

TPG may yet consider other options such as an initial public offering or a dividend recapitalization should a deal fail to materialize, the person added.

Representatives for Aptalis, Sun Pharma and Forest Laboratories did not immediately respond to requests for comment. TPG, Elan, Salix, JPMorgan and Evercore declined to comment.

TPG, one of the most active private equity investors in healthcare, bought the drugmaker, formerly known as Axcan Pharma, for $1.3 billion in 2008 and merged it with Eurand Pharmaceuticals in 2011. The combined company was renamed Aptalis.

The specialty pharmaceutical company has a number of drugs that treat cystic fibrosis and gastrointestinal disorders and sells the products primarily in North America and Europe.

In fiscal 2012, Aptalis was projected to have $615 million in revenue and $269 million in adjusted earnings before interest, tax, depreciation and amortization (EBITDA), according to its website.

The exploration of a potential sale comes at a time when there has been a flurry of deals in the pharmaceutical space over the past few months.

Among other deals, this year saw the announcement of Actavis Inc's (>> Actavis Inc) $5 billion acquisition of Dublin-based Warner Chilcott Plc (>> Warner Chilcott Plc), as well as the $8.7 billion takeover of eye care company Bausch & Lomb Holdings by Valeant Pharmaceuticals International (>> Valeant Pharmaceuticals Intl Inc).

(Reporting by Jessica Toonkel and Soyoung Kim in New York, additional reporting by Greg Roumeliotis in New York; Editing by John Wallace, Andrew Hay and Phil Berlowitz)

By Jessica Toonkel and Soyoung Kim