Smerdov, who was arrested August 15, was previously a witness in a high-profile inquiry into corruption in Russia's Mandatory Medical Insurance Fund (FOMS) opened late last year.
FOMS executives were accused of accepting bribes from the heads of regional branches of the fund, and pharmaceutical and other commercial companies involved in distributing medication and medical equipment under a state-run program to provide free or subsidized drugs to low-income population groups.
Smerdov's lawyers have appealed against his arrest and the court's refusal to release him on bail of 2 million rubles ($78,000).
"We have filed an appeal with the Moscow City Court against the Basmanny Court's ruling to arrest Smerdov, as it is illegal and unjustified," lawyer Eduard Safronsky said, adding that the defense team's request for bail had not been mentioned in the custody ruling.
Prosecutors said in their request to sanction Smerdov's arrest that he could escape abroad or exert pressure on witnesses. But Safronsky said his client had traveled abroad several times when he was a witness in the FOMS case, and had always returned.