Biopharmaceutical and pharmacokinetic characterization of sodium alendronate-loaded self-double-emulsifying drug delivery systems (SDEDDS)

The poor intestinal permeability of sodium alendronate (NaALD), a BCS Class III drug, severely limits its oral bioavailability. The self-double-emulsifying drug delivery system (SDEDDS) formulation containing phosphatidylcholine (PLG 1.1) demonstrated its ability to form micro- and nano-emulsions under gastric and intestinal conditions, as well as superior permeation across a biomimetic membrane in vitro , achieving 88% drug transfer. The self-emulsification time of both formulations was consistent with the average gastric transit time. In a rat model, the PLG 1.1 system significantly enhanced bioavailability, resulting in a 1.8-fold increase in cumulative urinary excretion of NaALD over 48 hours compared to a reference. In contrast, the other formulation, which did not contain phosphatidylcholine (Smix1 3.0), showed no improvement. It was concluded that the phosphatidylcholine-based SDEDDS represents a viable strategy to overcome the permeability barrier and improve the oral absorption of alendronate.