Single-dose pharmacokinetics of Madopar HBS in patients and effect of food and antacid on the absorption of Madopar HBS in volunteers.

Pharmacokinetic studies in parkinsonian patients and healthy volunteers have shown that Madopar HBS behaves as a slow-release formulation of L-dopa and benserazide. In comparison with standard Madopar the rate of absorption is reduced, providing lower peak concentrations of L-dopa. The drug is released and absorbed over a period of 4-5 h, thus maintaining substantial plasma concentrations for 6-8 h after dosing. Although the bioavailability after oral dosing is reduced as compared with standard Madopar (60-70%), this difference seems to be due to incomplete absorption rather than altered disposition of the drug. The presence or absence of food in the stomach has no effect on the absorption of L-dopa from Madopar HBS, but administration of antacids further reduces the bioavailability (45%).