Berberine (BBR), an isoquinoline alkaloid (Fig. 1), is isolated from many medicinal herbs, such as Coptidis rhizome (Coptis chinensis Franch.) and Cortex phellodendri (Phellodendron chinense C.K.Schneid.) (1). BBR has been used to treat microbial infection, diarrhea, and other gastrointestinal (GI) diseases due to its antibacterial, antidiarrheal and strong antidotal properties (2, 3). In recent years, much focus has been put on its other potential bioactivities, such as antihyperlipidaemic (4-6) and antidiabetic (7, 8) properties. However, Due to the very low oral bioavailability of BBR (below 1%) (9, 10) and its long-term administration for clinical treatment, high doses (0.9–1.5 g/day) usually trigger adverse GI effects including constipation, flatulence and abdominal pain (5), which drastically limits its practical uses. Until now, several studies have focused on improving the low oral bioavailability of BBR (11, 12), while the extent of bioavailability enhancement was limited. Thus, to improve the bioavailability of BBR effectively, it is essential to find out the factors that lead to its low oral bioavailability.
So far, the reasons of BBR’s low …show more content…
Group one were given water solution intravenously to calculate the absolute bioavailability (Fa) of BBR. Group two and group three were given water suspension and solution through intragastric administration, respectively, to evaluate the effect of drug dissolution state on the oral bioavailability. Group four were given water suspension with C10 to assess the influence of permeability enhancer on the oral absorption. the At intervals of 0.17, 0.5, 1.0, 1.5, 2.0, 4.0, 6.0, 8.0, 10.0, and 12.0 h after administration, blood samples (0.35 mL) were withdrawn from the ocular veniplex and placed in heparinized tubes. Plasma was obtained through centrifugation at 10000 rpm for 10 min and stored at −20°C until