Self-Nanoemulsifying/ Self-Assembled Cubic Nanoparticles Lyophilized Tablet: A Novel Biphasic Release Approach to Enhance the Bioavailability of a Lipophilic Drug

This study aimed to prepare a combined self-nanoemulsifying and self-assembled cubic nanoparticles (SNE/SAC) lyophilized tablet eliciting biphasic release pattern escorted with enhanced bioavailability for drugs hampered with slow dissolution and poor absorption. The antimuscarinic Darifenacin hydrobromide (DRF) was selected as a model drug used to treat overactive bladder-associated nocturia. The DRF-SNE/SAC lyophilized tablet was prepared so that upon reconstitution a mixture of DRF-loaded cubic nanoparticles and nanoemulsion dispersion is obtained. The nanoemulsion portion is responsible for the fast release followed by controlled release of the remaining dose loaded in cubic nanoparticles. A comparative pharmacokinetic study adopting randomized crossover design in male albino rabbits versus marketed product Frequefenacine® tablet was performed. Half of the dose (52.05% ± 4.21%) was rapidly released in the first 4 h followed by sustained release of the remaining drug where (90.16% ± 8.85%) was released in 24 h. The tested system showed 2.45 folds higher % relative bioavailability and 1.57 folds higher C_max with 1.62 longer residence time relative to reference product. The results endow the ability of the developed DRF-SNE/SAC lyophilized tablet to be considered as a propitious approach for the treatment of overactive bladder-associated nocturia without midnight dose administration.

Graphical Abstract