Short note: Infliximab recovery in a simulated intestinal fluid of the upper intestine tract.

Background: The oral administration of Infliximab (IFX) antibody would ensure a direct action on inflamed intestinal tissues without side effects. Thus, investigations about its resilience within the intestinal environment are required.

Objective: Quantify the IFX recovery in a simulated upper intestinal environment.

Methods: IFX was incubated for different times until 120 min in simulated intestinal fluid (SIF) which differed (i) for pH (7.2 vs 6.8, Exp 1), (ii) for addition or not with pancreatin (Exp 2) and (iii) for addition or not with bovine serum albumin in presence of pancreatin (BSA, Exp 3).

Results: In Exp 1 the IFX incubated without pancreatin was degraded by about 15% by SIF pH change from 7.2 to 6.8 and after 120 min it was reduced by about 20%. In Exp 2 the presence of pancreatin determined an intense and rapid IFX degradation (recovery < 33%, within 30 min), but when BSA was added to simulate the presence of food protein (Exp 3) the IFX half-life ranged between 59 and 70 min.

Conclusions: A discrete in vitro stability of IFX in the upper intestine environment was demonstrated, if food protein is available and competes with pancreatin proteases.