Ibopamine (SK&F 100168) pharmacokinetics in relation to the timing of meals

The effect of the timing of a standard meal relative to a single oral dose of 200 mg ibopamine, on the appearance of its pharmacologically active metabolite, epinine, in plasma was investigated in a randomised crossover study in 12 healthy volunteers. After a 12 h fast, ibopamine was administered either in the fasting state (no meal), or 1 h before, 0.5 h before, immediately after, 2 h after or 3 h after a standardised meal. Blood samples taken immediately before and at intervals for 3 h after dosing were analysed for free epinine. Maximum concentration (Cmax), time to Cmax(tmax), and area under the concentration-time curve (AUC) for free epinine in plasma were calculated. When compared with the fasting state, Cmax and AUC0-3h were significantly reduced when ibopamine was given immediately after or 2 h after a meal. AUC was also reduced for ibopamine given 0.5 h before a meal. tmax was significantly delayed when ibopamine was given immediately after, or 2 or 3 h after a meal. Thus, administration of ibopamine with or shortly after a meal reduced the rate and extent of appearance of free epinine in plasma. The clinical significance of reduced epinine levels on acute dosing in the presence of food is unknown.