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The purpose of this study is to investigate the influence of
antacids on the disintegration of enteric coated drugs. The
antacids and enteric coated tablets are collected from National
Taiwan University Hospital. The quality of the antacids, in
terms of preliminary antacid test (PAT) and neutralizing
capacity (ANC) , as well as the quality of the enteric coated
tablets, in terms of disintegration time were tested according
to USP XXIII. In addition, the buffering capacity of antacids
was tested in simulated physiological gastric secretion.
According to USP XXIII criteria,Obira gel,showing a pH below
3.5 in preliminary antacid test (PAT), should not be labeled as
an antacid, and was excluded from further experiment. The
influence of the antacids on the disintegration of enteric
coated tablets was tested by the following methods : I、tested
according to USP XXIII with modification by adding the antacid
to simulated gastric juice in the proportion of clinical dose /
physiological gastric volume; II、tested in the mixture of
antacids and simulated gastric juice with constant stirring on
a stirer; III、tested in a mixture of simulated gastric juice
containing a dose of antacid, with constant input (1.8 ml/min)
of fresh simulated gastric juice and drainage of an equal
volume of the reaction mixture from the container. The results
demonstrated that the enteric coating of Dulcolax and Ecotrin
were tolerable to any of the antacids in the three methods,
while that of Voren was the most labile to any of the antacids
in method I and II. NaHCO3 and Fanta 20ml showed the most
strong effects,causing disintegration of the five enteric
coated tablets in method I. On the contrary, Nacid, either 1 or
2 tablets, did not influence the disintegration of the five
enteric coated tablets in the three methods. CaCO3 and Fanta
10ml were moderate,causing disintegration of most tablets only
in method
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