Chester County Senior Deputy Attorney General Nancy S. Hartsough said the District Attorney's Office was reviewing a possible appeal.
"I'm confident we can prove the charges that remain," she said, adding that Richard Brown still faces "significant" jail time.
In December 2001, Brown was charged with dispensing illegal narcotics from his home office on Old Eagle School Road. He pleaded no contest, received probation, and agreed to relinquish his medical license.
In May 2007, Brown was rearrested on more than 800 charges. A grand-jury report accused him of continuing illicit drug sales to known addicts in 2002, 2003, and 2004, evading income taxes from 2002 through 2005, and fraudulently obtaining his medical license in 1985.
Baer said his client self-reported "his 2003 conviction to the state medical board within the 60-day requirement," which authorities dispute. The state did not revoke Brown's license until July 2004, a delay that led to the earlier dismissal of charges.
In July, Nagle ruled that the statute of limitations had expired on about 270 charges, including allegations that Brown used forgery and deception to obtain his medical credentials.
"Accordingly, the commonwealth is unable as a matter of law to prove Brown was not a licensed physician before July 1, 2004," Nagle wrote, explaining the dismissal of charges related to being "an unlicensed medical professional."
The judge also dismissed a second set of tax charges filed in July against the couple. He concluded that Richard Brown, as executor of his father's estate, did nothing illegal when he deferred payment of a $55,000 estate commission and claimed a poverty-tax credit in 2006.
Prosecutors said that during that time, Brown also had access to his $1 million inheritance and used almost half of it to pay his expenses.
Tax charges filed in May 2007 remain against both Browns, who are accused of underreporting their income and fraudulently claiming a poverty credit for the tax years 2002 through 2005.
Contact staff writer Kathleen Brady Shea at 610-696-3815 or firstname.lastname@example.org.