COMPARATIVE DISSOLUTION STUDIES OF RECTAL FORMULATIONS USING THE BASKET, THE PADDLE AND THE FLOW-THROUGH METHODS .2. IBUPROFEN IN SUPPOSITORIES OF BOTH HYDROPHILIC AND LIPOPHILIC TYPES

The applicabilities of the paddle, basket and flow-through methods hav e been investigated for four different rectal compositions of both hyd rophilic and lipophilic types containing ibuprofen. The formulations w ere studied with respect to in vitro dissolution rate and behaviour in the different apparatus. The reproducibility of the three techniques was also tested by using a hydrophilic and a lipophilic composition. N one of the techniques appeared to be more applicable than the others f or the compositions tested, though the dissolving suppositories are le ss sensitive to the technique used than the melting ones. It has been found necessary to consider the behaviour of the product, with regard to its composition and the in vitro method used, when judging the appl icability of a dissolution test for a rectal dosage system. Comparison to our previous data on paracetamol also shows that the physical-chem ical properties of the drug substance are of great importance, and mus t be considered, when the judgement of applicability is made.