Human gastrointestinal absorption of acyclovir from tablet duodenal infusion and sipped solution

Abstract

On two occasions at least 1 week apart, nine healthy male volunteers were administered in random order either 2 X 200 mg (1.8 mmol) acyclovir tablets or 400 mg of acyclovir in 500 ml of 5% dextrose solution which was infused at constant rate into the duodenum over 4 h. Six of the subjects subsequently sipped the same solution at the rate of 10.4 ml in each 5 min period for 4 h. Blood and urine were sampled over 24 h for each mode of administration. Acyclovir was assayed by radioimmunoassay. Mean areas under the plasma concentration-time curves (AUCs) +/- s.d. for tablet (T), intraduodenal infusion (I) and sipping (S) were, respectively: T = 14.7 +/- 5.1; I = 24.6 +/- 5.1; S = 28.4 +/- 9.5 (n = 6) mumol l-1 h. AUCs for I and S were significantly greater than that for T (2P less than 0.05). Mean apparent maximum plasma concentrations (Cmax) +/- s.d. were T = 3.8 +/- 1.5; I = 4.8 +/- 0.9; S = 5.1 +/- 1.5 mumol l-1. This trend to higher values for I and S was not significant. Mean apparent plasma disappearance half-lives (t1/2) +/- s.d. were respectively T = 2.3 +/- 0.4; I = 2.7 +/- 0.5; S = 3.0 +/- 0.2 h, I being significantly greater than T (2P less than 0.05), as was S greater than T (2P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)