WINSTON-Targacept, which filed for an initial public offering in May, has closed on another big round of fund-raising.

The biopharmaceutical firm focused on drugs to treat nervous system disorders, said Wednesday that it has closed on $33 million in a private placement.

Targacept said existing investors participated, with Nomura Phase4 Ventures out of London leading the round.

Venture Wire reported on Thursday that an investor said Targacept limited the number of investors in order to avoid having to revise its IPO filing. “Not everyone was able to participate,” he told Venture Wire, implying that investors wanted in.

In 2003, Targacept closed on $60 million in B-round financing that was raised over 2002-3. Normura International’s Healthcare Private Equity Group led the round.

Proceeds from the latest financing will be used for clinical development of its lead candidates, Targacept said in a brief statement.

Targacept is developing drugs to selectively target neuronal nicotinic acetylcholine receptors, or NNRs. These receptors are found on nerve cells throughout the nervous system.

When Targacept filed to go public, it was to be represented by Morgan Stanley, Deutsche Bank Securities Inc., CIBC World Markets and Pacific Growth Equities.

Targacept was spun out of RJR Reynolds in 2000 and had raised nearly $90 million before Wednesday’s announcement.

Other investors in Targacept have included Oxford Bioscience Partners, JAFCO, Cogene Biotech Ventures, Bison Capital, Rock Castle Ventures, New Enterprise Associates (NEA), CDIB BioScience Ventures, Easton Hunt Capital Partners, EuclidSR Partners, Burrill & Company, Advent Venture Partners, Auriga Ventures, CDC-IXIS Innovation, Genavent Fund, SGAM Biotechnology Fund and Academy Venture Fund.