EFFECT OF MICROCAPSULATION ON ABSORPTION PROCESSES IN THE PIG

The effect of microcapsulation with long-chain fatty acids (LCFA) on t he absorption and bioavailability of nutrients and drugs was studied i n pigs using microcapsulated tryptophan (TRY) and sulfamethazine (SMT) . Portal concentrations of tryptophan were monitored in gilts fed a ba sal diet supplemented with 1.75 and 10.75 g pig(-1) day(-1) free-cryst alline or microcapsulated TRY. Sulfamethazine plasma kinetics were stu died in gilts orally administered with free-base or microcapsulated dr ugs (1 g pig(-1)) at feeding time. Blood samples were collected until 8 h and 120 h after feeding in pigs treated with TRY and SMT, respecti vely. Absorbed fractions of both microcapsulated TRY and SMT were lowe r than in the free forms by 26 and 32%, respectively, 8 h after treatm ent. Nevertheless, total drug bioavailability measured by the area und er the plasma concentration-time curve extrapolated to infinity (AUC(0 -infinity)) was not modified by microcapsulation (970 +/- 202 vs. 959 +/- 355 mu g ml(-1) h). These data suggest that microcapsulation delay s absorption without affecting the bioavailability of protected compou nds. (C) 1997 Elsevier Science B.V.