Dissolution of omeprazole from delayed-release solid oral dosage forms

The evaluation of the biopharmaceutical quality of omeprazole enteric-coate d products (granules in capsules) with respect to its dissolution character istics is not specifically regulated in any of the most common official pha ramcopoeia. USP 23 includes a general monograph for enteric-coated products . This paper reports the evaluation of the medium pH effect on the dissolut ion rates of omeprazole from four omeprazole-containing products of differe nt manufacturers. It is concluded that the USP 23 recommended dissolution p rocedure for enteric-coated products is not suitable due to the degradation of omeprazole under such conditions. Furthermore, the medium wit pH 8.0 sh owed different dissolution rates not observed at pH 7.4 allowing discrimina tion between products of different manufacturers.