GASTRIC-EMPTYING OF 2 RADIOLABELED ANTACIDS WITH SIMULTANEOUS MONITORING OF GASTRIC PH

The aim of this study was to assess the gastric emptying rate of two a ntacids using an scintigraphic technique and simultaneous monitoring o f gastric pH in 16 healthy male volunteers. Ten mi of Talcid (hydrotal cite 1 g) and Maalox (Mg-Al-hydroxide), with a similar neutralization capacity, were labelled with technetium-99m using a pyrophosphate brid ge. Labelled antacids were given on separate days (within 2 weeks), 1 h after a standard meal. Intragastric pH was measured for at least 4 h , using ambulatory pH-metry with a dual-crystant antimony catheter. Co ntinuous monitoring was started Ih prior to the meal (baseline) and la sted 3 h (post-prandial, post-antacid and final periods). The antacid capacity of labelled and unlabelled antacids was similar. The mean per centages of antacids retained in the stomach fitted a linear model. Th e mean half-emptying time of Talcid was 63.9+/-27.9 min, while that of Maalox was 57.3+/-23.9 min (P=NS). The recordings of gastric pH (mean values of pH for each period) showed a similar profile for both antac ids. The mean pH (Maalox vs Talcid) was 1.69 vs 2.07 in the baseline p eriod, 1.95 vs 1.93 in the postprandial period, 1.79 vs 1.15 in the po st-antacid period (P=NS) and 0.4 vs 0.52 in the final period (P<0.05 v s prior periods). In conclusion, the gastric emptying of Talcid and Ma alox was similar and pH profiles were parallel and remained unchanged for the two antacids within the first hour of intake. A significant de crease in pH was observed 1 h after intake of the antacids, suggesting a possible rebound effect.