Distribution to human peripheral lymph of amoxycillin and of ampicillin from the oral prodrug bacampicillin.

Equivalent doses of 1600 mumol each of amoxycillin (582 mg) and ampicillin from bacampicillin (800 mg) were studied in five fasting healthy volunteers in a cross-over study. Peripheral lymph was collected from the legs by cannulation of subcutaneous lymph vessels. Antibiotic concentrations were determined by bioassay. Passage to the lymph was rapid; for both agents lymph peaks occurred between 1-2 h after serum maxima. The compounds showed similar ranges of serum and of lymph concentrations; the mean individual peak concentration, area under the concentration curves, and elimination half-life in serum were 9.6 mg/l, 24.8 mg.h/l, and 0.80 h respectively for amoxycillin and 11.0 mg/l, 21.4 mg.h/l, and 0.93 h for ampicillin from bacampicillin. In lymph, the corresponding values were 5.5 mg/l, 21.9 mg.h/l, and 1.1 h for amoxycillin and 4.7 mg/l, 16.1 mg/l, and 1.0 h for ampicillin. The ratios between concentrations in lymph and serum were similar. The ratios between the total areas under the concentration curves was 0.88 +/- 0.19 for amoxycillin compared to 0.80 +/- 0.10 for ampicillin from bacampicillin. The areas under the lymph concentration vs. time curves ranged from 69-107% of the serum curve values of amoxycillin and 71-97% for ampicillin. Both drugs persisted longer in lymph than in serum. This pattern was somewhat more pronounced for amoxycillin, probably because of its more sustained serum concentrations due to delayed absorption. Thus the two antibiotics were similar in respect to passage into peripheral lymph.

RCT Entities:   Population Interventions Outcomes