In vitro detection of possible in vivo drug interactions. Part 1. The effect of hydrochlorothiazide and frusemide on the in vitro absorption characteristics of propranolol hydrochloride.

The Sartorius absorption simulator was used as a device to detect possible in vivo gastrointestinal tract drug interactions. The drugs chosen were propranolol hydrochloride and two diuretics (namely hydrochlorothiazide and frusemide) commonly used in conjunction with propranolol hydrochloride for the treatment of hypertension. The results show that the presence of both diuretics increased the intestinal absorption rate constant and the percentage diffused of propranolol hydrochloride. Moreover, the presence of propranolol hydrochloride also caused the intestinal absorption rate constants and the percentages diffused of both diuretics to be increased.