A phospholipid complex to improve the oral bioavailability of flavonoids

Abstract

Aim: A phospholipid complex (TFH-PC) was prepared to increase the oral bioavailability of isorhamnetin, kaempferol, and quercetin from TFH (total flavones of Hippophae rhamnoides L.).

Methods: Solvent evaporation was used to prepare TFH-PC. Relevant parameters were investigated based on the complexation rate of isorhamnetin, kaempferol, and quercetin. Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), X-ray power diffraction (X-RPD), and scanning electron microscopy (SEM) were used for characterization. Solubility, octanol–water partition coefficient (log P), dissolution rate, and in vivo pharmacokinetics were also investigated.

Results: TFH-PC was successfully prepared in tetrahydrofuran with a drug to phospholipid ratio of 1:1, reaction temperature of 20 °C, and a reaction time of 1 h. The complexation rates of isorhamnetin, kaempferol, and quercetin were 97.7%, 95.97%, and 92.23%, respectively. FT-IR, DSC, X-RPD, and SEM confirmed the formation of TFH-PC. The aqueous solubilities of the three flavonoids in TFH-PC increased 22.0–26.8-fold compared with TFH. The dissolution of isorhamnetin, kaempferol, and quercetin in TFH-PC was 84.32%, 90.77%, and 100% within 10 min, respectively, greatly improved over TFH. After oral administration of TFH-PC in rats, the bioavailability of isorhamnetin, kaempferol, and quercetin in TFH-PC relative to TFH was 223%, 172%, and 242%, respectively.

Conclusion: The oral absorption of isorhamnetin, kaempferol, and quercetin was significantly improved in TFH-PC, mainly due to increased solubility and dissolution rate. This phospholipid complex shows potential for oral delivery of the flavonoids in TFH.

• Dissolution rate
• flavonoids
• oral absorption
• phospholipid complex
• solubility

Declaration of interest

The authors declare no conflicts of interest. This study was sponsored by the National Science Foundation of China (81303304), the Innovation Program of the Shanghai Municipal Education Commission (14YZ057), the Specialized Research Fund for the Doctoral Program of Higher Education (20133107120006), the Medical Program of Hongkou District (1301-01), and the Shanghai Talent Development Fund (201369).