Stabilizing excipients for engineered clopidogrel bisulfate procubosome derived in situ cubosomes for enhanced intestinal dissolution: Stability and bioavailability considerations

Clopidogrel bisulfate (CB) is a golden antiplatelet treatment, yet its benefits are limited by its low bioavailability (< 50%) caused by poor intestinal solubility and absorption. The present study aims to improve CB intestinal solubility and absorption through developing a novel stable dry CB procubosomes tablets ready to disintegrate and re-disperse upon dilution in the GIT forming in situ CB cubosome nanoparticles while simultaneously overcome the poor stability of conventional cubosome dispersion at room temperature. Glyceryl monooleate based CB cubosome dispersion was prepared using Poloxamer 407 as surfactant, freeze dried using different stabilizing excipients (dextrose, mannitol and avicel) then compressed into procubosome tablets. The effect of excipient's physicochemical properties on the flowability, in vitro dissolution and stability at accelerated conditions (40 +/- 2 degrees C/75 +/- 5% RH) were evaluated. The prepared procubosomes exhibited an excipient type dependent dissolution profile where Avicel based procubosome tablet CF2 showed the highest in vitro dissolution profile among other excipients used during the freeze drying process. Upon transition to intestinal pH of 6.8 to mimic the drug absorption site, CF2 procubosome Avicel tablet, was able to preserve the enhanced CB release profile (99.6 +/- 6.92%) compared to commercial Plavix (R) where, CB dissolved % dropped dramatically to 79.1 +/- 2.45%. After storage for six months, CF2 retained the fresh tablet drug content of 98.5 +/- 5.82% and dissolution properties. Moreover, following oral administration in rabbits, CF2 showed higher relative bioavailability (153%) compared to commercial Plavix (R) with significant higher C-max, shorter t(max), as well as enhanced antiplatelet activity.