Effects of Borneol on the Release of Compound Danshen Colon-Specific Osmotic Pump Capsule In Vitro and Pharmacokinetics Study in Beagle Dogs

Borneol can enhance the bioavailability of several other drugs by opening the blood-brain barrier and inhibiting P-glycoprotein (P-gp) efflux. However, whether borneol will impact the bioavailability and the mechanism of compound Danshen colon-specific osmotic pump capsule (CDCOPC) remains unclear. This study aimed to determine the effects of borneol on the in vitro release and in vivo pharmacokinetic characteristics of CDCOPC. Besides, the in vitro release behavior of CDCOPC was further assessed by chromatographic fingerprints. The in vitro release studies showed that borneol followed the zero-order release and hardly impacted the in vitro release of Salvia miltiorrhiza and Panax notoginseng in CDCOPC. Moreover, as revealed from the similarity results of fingerprints, the in vitro release of different components of CDCOPC was almost simultaneous. Compared with the commercially available tablets, the pharmacokinetics studies suggested that both CDCOPCs containing and lacking borneol could significantly prolong the retention time of these effective components; their average relative bioavailability values increased to 448.70% and 350.97%, respectively. Notably, borneol significantly improved the relative bioavailability of some components of CDCOPC, such as salvianolic acid B (SAB), tanshinone IIA (Tan IIA), notoginsenoside R₁ (R₁), ginsenoside Rg₁ (Rg₁), and ginsenoside Re (Re) from CDCOPC, while it slightly impacted ginsenoside Rb₁ (Rb₁) and ginsenoside Rd (Rd). Summarily, borneol is capable of improving the bioavailability of some effective components in CDCOPC, which is critical to design with CDCOPC for enhanced bioavailability. This study could also help reveal the composition principle of the compound Danshen formula (CDF).