SANTA ROSA -- Shares of stock in Santa Rosa-based startup pharmaceutical developer Ruthigen, Inc., (Nasdaq: RTGN) fell after the initial public offering Monday on the NASDAQ exchange.

Ruthigen (707-525-9900, set the price of the IPO at $7.25 a share Friday afternoon. The goal for the wholly owned subsidiary of Petaluma-based Oculus Innovative Sciences is to raise $19.2 million from issuance of more than 2.65 million shares for discovery, development and commercialization of a pharmaceutical acid designed to prevent and treat infections.

The stock began trading at trading Monday at $7.40 and ended the session at $6.76, down 6.76 percent, or 49 cents a share, from the IPO price. Yet, it was a down day for pharmaceutical stocks and Wall Street overall Monday, with prices slipping more than 1 percent for the industry and Nasdaq indices. Oculus' stock price slipped about 1 percent, or 5 cents a share, to $4.87.

Ruthigen's stock price rebounded Tuesday, closing at $7 a share.

The number of shares in Ruthigen's IPO were more than it initially anticipated when it spun off from Oculus last year.

Last year, Ruthigen said it would seek up to $26.7 million to finance and develop RUT58-60, its flagship drug that has shown promise in preventing and treating surgical infections.  The offering is expected to close on March 26, , subject to customary closing conditions.

Ruthigen said it plans to begin enrolling patients in phase 1 and phase 2 clinical trials this July for the flagship drug. Upon completion, Ruthigen would submit the new drug to the U.S. Food and Drug Administration for approval by late 2017.Dawson James Securities, Inc., is the sole book-running manager for the underwritten offering.Ruthigen estimated iIPO net proceeds of $15.4 million, or about $18 million if its underwriters exercise all their stock and warrant options.