| A B S T R A C T
Objective: The aim of the current study was firstly to identify polymers which
effectively inhibit precipitation of Dipyridamole (DP), a poorly water-soluble basic drug, in neutral solution. Secondly, to test the viability of formulation approaches
where a component is used to enhance the dissolution of DP at a neutral solution, while another component is added to inhibit its precipitation.
Methods: The effectiveness of some Eudragit polymers in inhibition of DP precipitation was evaluated. Solid dispersion technology using enteric polymer, Eudragit L
100-55 (Eu L100-55), or pH-modifier technology employing an appropriate acidifier, Tartaric acid (Tar), were used to enhance the dissolution of DP in neutral
solution, while an effective polymer, was added to inhibit the DP precipitation. FT-IR, differential scanning calorimetry and dissolution testing were used to
characterize the formulations.
Results: The results indicated that Eudragit E (Eu E) inhibited DP precipitation the most, probably owing to interaction with DP, as verified by FT-IR. Dissolution
results revealed that addition of Eu E to Eu L100-55-based formulations led to an inconsiderable improvement in dissolution rate of DP. But, the inclusion of Eu E into
Tar-based formulations exhibited not only stability to precipitation but also higher maximum achievable concentration level of DP, demonstrating more efficiency in
offering dissolution benefits in comparison to the predicted dissolution performances which only account for additive influences.
Conclusion: Results demonstrated that the choice of suitable components with the capacity to act complementary to each other, is vital to the success of the strategy
formulation of this work. |