Assemblage of drug release modules: effect of module shape and position in the assembled systems on floating behavior and release rate.

The aim of this work was to study the clindamycin release kinetics from floating delivery systems consisting of two modules assembled in void configuration, according to the modified release technology platform known as Dome Matrix®. Two modules differently shaped, i.e., female and male, formulated as swellable matrices and containing clindamycin, were assembled by friction interlocking. Then, by stacking additional female modules without drug on the assembled two-module floating system, modulation of clindamycin release rate and kinetics was attained. The additional modules stacked on the assembled system acted as a transient barrier to clindamycin release from the void configuration. Inertness, dissolution/erosion or swelling behavior characterized their performance as matrices in simulated gastric fluid. In particular, we found that stacking additional barrier modules on the bases of void configuration, the drug release rate and kinetics of the assembled system were modified in dependence on the composition of module added. In particular, the quickly soluble module exerted an influence on the release rate in the late time of delivery. The swellable module produced a significant reduction in release rate of void assembly, but the release mechanism remained the same. Finally, the inert module led to a substantial linearization of the release profile with a minimal reduction in release rate.