A novel oral preparation of hydroxysafflor yellow A base on a chitosan complex: a strategy to enhance the oral bioavailability.

Hydroxysafflor yellow A (HSYA), the main active pharmaceutical ingredient of the safflower plant (Carthamus tinctorius L.), is a hydrophilic drug with low oral bioavailability (BA). The objective of the present study was to improve the oral BA of HSYA by formulation design. The effect of several pharmaceutical excipients on enhancing BA, including Poloxamer 188 (P188), sodium caprate (SC), sodium deoxycholate, and β-cyclodextrin (β-CD), was investigated through animal models. Sodium caprate, with a relative BA of 284.2%, was able to improve the oral BA of HSYA. Furthermore, HSYA can bind with chitosan (CS) by Coulomb attraction and form a HSYA-CS complex. The preparation process was optimized, and the binding rate reached 99.4%. HSYA granules were prepared using a HSYA-CS complex and SC. The results of the pharmacokinetics showed that the relative BA of HSYA granules was 476%, much higher than HSYA/SC.