Characterization and Bioavailability Study of Baicalin-mesoporous Carbon Nanopowder Solid Dispersion.

Baicalin is the main bioactive constitute of the dried roots of Scutellaria baicalensis and possesses various biological activities. However, the poor water solubility and low oral bioavailability limit its efficacy.The present study was conducted to enhance the dissolution and oral bioavailability of baicalin (BA) through a novel mesoporous carbon nanopowder (MCN) drug carrier.Solid dispersions (SDs) of BA with MCN were prepared using a solvent evaporation method. The physical state of the formulations was investigated using SEM, differential scanning calorimetry (DSC) and powder X-ray diffraction (XRD). The pharmaceutical performance of pure BA, physical mixture (PM) and SDs was evaluated by performing an in-vitro dissolution test. The pharmacokinetic studies were conducted in SD rats and the analysis of the biological samples was performed on an Acquity UPLC-MS system. The intestinal and renal toxicity test of MCN was also evaluated.The drug release profile indicated that the BA dissolution rate from SDs with a BA/MCN ratio of 1:6 greatly increased in comparison with that of the pure crystalline drug. Furthermore, a pharmacokinetic analysis in rats showed that the BA area under the concentration-time curve for SDs of MCN/BA was 1.83 times larger than that of pure BA. In comparison with the pure drug, the MCN-BA system significantly shortened the time to Tmax and generated higher Cmax. There was no intestinal and renal toxicity of MCN.These results indicated that the oral bioavailability of BA was remarkably improved by the MCN carrier. Additionally, intestinal toxicity test showed that MCN produced no toxicity in the gastrointestinal tract. Our results show that MCN-based SDs could be used to enhance the bioavailability of drugs with poor water solubility.The drug release profile indicated that the BA dissolution rate from SDs with a BA/MCN ratio of 1:6 greatly increased in comparison with that of the pure crystalline drug.Furthermore, a pharmacokinetic analysis in rats showed that the BA area under the concentration-time curve for SDs of MCN/BA was 1.83 times larger than that of pure BA.In comparison with the pure drug, the MCN-BA system significantly shortened the time to Tmax and generated higher CmaxAbbreviations used: BA: baicalin, MCN: mesoporous carbon nanopowder, SDs: solid dispersions, SEM: scanning electron microscopy, DSC: differential scanning calorimetry, XRD: powder X-ray diffraction, HPLC: high-performance liquid chromatography, PM: physical mixture, S.D.: standard deviation, ANOVA: analysis of variance, RSD: relative standard deviation, ESI: electrospray ionization, IS: internal standard, MRM: multiple reaction monitoring.