Talecris Biotherapeutics, which uses plasma to create therapies for chronic diseases, said Friday it plans to raise as much as $1 billion by selling stock to the public.

The Research Triangle Park company, which has a plant in Clayton, did not disclose the number of shares it will sell or the price of those shares in its filing with the Securities & Exchange Commission. There's no way to know when the initial public offering could take place.

But if it raises anything near the estimate, the IPO will be one of the largest for a Triangle company.

Talecris officials could not be reached for comment late Friday, but the filing comes amid sharp Wall Street declines and likely reflects the desire of the owners -- two private equity firms -- to cash out their stakes before the opportunity to do so withers.

Talecris was formed two years ago when Cerberus Capital Management of New York and Ampersand Ventures of Massachusetts bought the business from Bayer, a German chemical giant.

It has blossomed since.

Talecris has boosted its work force from 1,600 to 3,472, purchased a plasma collection business and opened foreign offices.

Last year, it had profit of $87.4 million on revenue of $1.1 billion, according to the SEC filing. In the first three months of the year, sales jumped 6 percent to $302.4 million, but net income declined 7 percent on higher expenses.

The company has $1.13 billion in debt, a consequence of the way it was formed and a possible driver of the IPO timing.

Private equity firms, which pool funds from rich individuals and institutions, usually fund acquisitions by borrowing and putting the debt on the balance sheets of the companies they buy. After streamlining operations of their new acquisitions, they eventually sell stock to the public and make a handsome profit.

That model has flourished in recent years amid mountains of cheap money. But credit is tightening, and the private-equity boom is slowing.

"The whole cosmos of leveraged buyouts is in question right now," said Ben Holmes, head of Morningnotes.com, an IPO research firm in Colorado.

Private equity firms are finding it harder to get debt at favorable terms, and investors might have less appetite for the debt-laden companies they spit out.

Talecris said that it plans to use proceeds from the sale of stock to pay down its debt, pay dividends to current investors and pay a fee to terminate a management agreement with Cerberus and Ampersand. The balance, "if any," will be used to fund Talecris operations.

"That little phrase, 'if any,' tips us off that they're going to drain this stuff right into their pockets," Holmes said.

Among those poised to benefit from the stock sale are Lawrence D. Stern, the executive chairman, and Alberto Martinez, the chief executive. Stern received total compensation of almost $20 million last year, the SEC filing said. Martinez received $12.8 million.

The company plans to list on the Nasdaq under the symbol "TLCR."