Characterization and pharmacokinetic evaluation of natural composition self-assembled nanoemulsion

BACKGROUND: Nanophase is an effective drug delivery system. Self-assembling nanoemulsion (N-XY) was found in Xiaoyaosan; but its pharmacokinetics remain unclear. Objective: To explore the physicochemical properties, active components, release kinetics, and in vivo pharmacokinetic behavior of N-XY. Methods: Xiaoyaosan phase states were separated by centrifugal dialysis. N-XY was characterized using multiple analytical techniques, and active constituents against mammary gland hyperplasia were screened by HPLC fingerprinting combined with grey relational analysis (GRA). In vitro release was evaluated using dissolution studies, and in vivo pharmacokinetics were assessed in an animal model. In vitro-in vivo correlation (IVIVC) was established by linear regression analysis. Results:N-XY was isolated as a stable O/W nanoemulsion retaining key bioactive components. HPLC with GRA indicated nine components, including glycyrrhizic acid, contributed to anti-mammary hyperplasia effects. In vitro studies showed pH-responsive sustained release. Pharmacokinetics demonstrated prolonged in vivo retention and increased systemic exposure compared with A-XY, with significant IVIVC for the main bioactive components. Conclusion: N-XY is the primary bioactive phase of Xiaoyaosan, exhibiting intrinsic sustained-release and absorption-enhancing properties. This study not only elucidates the material basis and delivery characteristics of Xiaoyaosan but also provides a novel strategy for the rational development and identification of effective phases in traditional Chinese medicine formulas.