State Sen. Howard A. Denis, fresh from his defeat Wednesday during a long debate over new savings and loan regulations, took it on the chin again yesterday when he tried single-handedly to derail a bill that he said could drive a Rockville pharmaceutical company out of business.

The Montgomery County Republican argued in vain to stop legislation that would effectively prohibit physicians from dispensing medications if their offices are located within three miles of a pharmacy.

Denis argued that the measure, filed by his own committee chairman, Sen. Dennis F. Rasmussen (D-Baltimore County) at the request of the retail pharmacy lobby, would probably force out of business a Rockville company called Physicians' Pharmaceutical Services Inc., which supplies medicines to doctors.

Denis called the drug-dispensing legislation "the quintessential special-interest bill."

Supporters argued that it would help the state get some control over those doctors who dispense drugs, a practice that some critics charge has reached record levels.

Denis, one of the few senators who tried to further strengthen new S&L regulations during debate Wednesday, did win the support yesterday of his fellow Republicans and Montgomery County senators.

But the Senate approved the measure, 29 to 17, sending it to the House of Delegates.