Introduction: Berberine (BBR) is a plant-derived benzylisoquinoline alkaloid and has been demonstrated to be a potential treatment for various chronic diseases. The poor water solubility and P-glycoprotein (Pgp)-mediated drug efflux are the main challenges for its further application in a clinical setting.
Materials and methods: In this study, a Brij-S20 (BS20)-modified nanocrystal formulation (BBR-BS20-NCs) has been developed and investigated with the purpose of improving the intestinal absorption of BBR. The physicochemical properties of the developed BBR-BS20-NCs were characterized and the enhancement of the BBR-BS20-NCs on BBR absorption were investigated both in vitro and in vivo.
Results: The results indicated that BS20 could significantly enhance the intracellular uptake of BBR in MDCK-MDR1 cells via a short-term and reversible modulation on the Pgp function, accompanied by a marked increase in Pgp mRNA expression but without significant influence on the Pgp protein expression. Moreover, the morphology of the prepared BBR-BS20-NCs was observed to be prism-like, with a smooth surface and an average diameter of 148.0 ± 3.2 nm. Compared to raw BBR and physical mixture, BBR-BS20-NCs facilitated the dissolution rate and extent of release of BBR in aqueous solution, and further increased the absorption of BBR in MDCK-MDR1 monolayer by overcoming the Pgp-mediated secretory transport (P_app[BL-AP] values of 2.85 ± 0.04 × 10^-6 cm/s, 2.21 ± 0.14 × 10^-6 cm/s, and 2.00 ± 0.07 × 10^-6 cm/s for pure BBR, physical mixture, and BBR-BS20-NCs, respectively). Significant improvements in the maximum concentration observed (C_max) and area under drug concentration-time curve (AUC_0–t) of BBR-BS20-NCs were obtained in pharmacokinetic studies compared to pure BBR, and the relative bioavailability of BBR-BS20-NCs to pure BBR was 404.1%.
Conclusion: The developed BBR-BS20-NCs combine the advantages of nanocrystal formulation and functional excipient. The novel pharmaceutical design provides a new strategy to improve the oral bioavailability of those drugs with both poor water solubility and Pgp-mediated efflux.