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As a multi-target drug to treat ischemic stroke, N-butylphthalide (NBP) is extremely water-insoluble and exhibits limited oral bioavailability, impeding its wide oral application. Effective treatment of ischemic stroke by NBP requires timely and efficient drug exposure, necessitating the development of new oral formulations. Herein, liposomes containing biosurfactant sodium cholate (CA-liposomes) were systemically investigated as an oral NBP delivery platform because of its high biocompatibility and great potential for clinical applications. The optimized liposomes have a uniform hydrodynamic size of 104.30 �� 1.60 nm and excellent encapsulation efficiency (93.91 �� 1.10%). Intriguingly, NBP-loaded CA-liposomes produced rapid drug release and the cumulative release was up to 88.09 �� 4.04% during 12 h while that for NBP group was only 6.79 �� 0.99%. Caco-2 cell monolayer assay demonstrated the superior cell uptake and transport efficiency of NBP-loaded CA-liposomes than free NBP, which was mediated by passive diffusion via transcellular and paracellular routes. After oral administration to rats, NBP-loaded CA-liposomes exhibited rapid and almost complete drug absorption, with a tmax of 0.70 �� 0.14 h and an absolute bioavailability of 92.65% while NBP suspension demonstrated relatively low bioavailability (21.7%). Meanwhile, NBP-loaded CA-liposomes produced 18.30-fold drug concentration in the brain at 5 min compared with NBP suspension, and the brain bioavailability increased by 2.48-fold. As expected, NBP-loaded CA-liposomes demonstrated significant therapeutic efficacy in a middle cerebral artery occlusion rat model. Our study provides new insights for engineering oral formulations of NBP with fast and sufficient drug exposure against ischemic stroke in the clinic.

Although Fraxinellone (Frax) isolated from Dictamnus albus L. possessed excellent anti-hepatic fibrosis activity, oral administration of Frax suffered from the inefficient therapeutic outcome in vivo due to negligible oral absorption. At present, the oral formulation of Frax is rarely exploited. For rational formulation design, we evaluated preabsorption risks of Frax and found that Frax was rather stable while poorly dissolved in the gastrointestinal tract (78.88 μg/mL), which predominantly limited its oral absorption. Further solubility test revealed the outstanding capacity of cyclodextrin derivatives (CDs) to solubilize Frax (6.8–12.8 mg/mL). This led us to study the inclusion complexes of Frax with a series of CDs and holistically explore their drug delivery performance. Characterization techniques involving 1H-NMR, FT-IR, DSC, PXRD, and molecular docking confirmed the most stable binding interactions when Frax complexed with 6-O-α-D-maltosyl-β-cyclodextrin (G2-β-CD-Frax). Notably, G2-β-CD-Frax exhibited the highest solubilizing capacity, fast dissolution rate, and superior Caco-2 cell internalization with no obvious toxicity. Pharmacokinetic studies demonstrated markedly higher oral bioavailability of G2-β-CD-Frax (5.8-fold that of free drug) than other Frax-CDs. Further, long-term administration of G2-β-CD-Frax (5 mg/kg) efficiently inhibited CCl4-induced hepatic fibrosis in the mouse without inducing any toxicity. Our results will inspire the continued advancement of optimal oral Frax formulations for anti-fibrotic therapy.

We recently reported that the absolute oral bioavailability of flavonoid Morin was extremely low at 0.45%, resulting in unsatisfied therapeutic efficacy in vivo. The present study was aimed to systemically assess the pre-absorption risks of Morin for rationale formulation design. Physicochemical properties of Morin were evaluated using in vitro assays including water solubility and stability in simulated gastric, intestinal fluids, followed by permeability tests in Caco-2 cells. The results suggested that both poor solubility and low membrane permeability were rate-limiting steps for oral absorption of Morin. Pharmacokinetic studies were performed via a series of administration routes in a dual-vein cannulated rat model. In contrast to high bioavailability (92.92%) and negligible metabolites of Morin in intraportal administered rats, Morin exhibited low bioavailability (5.28%) and considerable amount of metabolites in rats following intraduodenal administration, suggested that intestinal first-pass metabolism made a major contribution to its poor oral absorption. Morin-phospholipid complex loaded self-emulsifying drug delivery system (MPC-SENDDS) exhibited comparable plasma concentration of metabolites to parent drug after oral administration, indicated that MPC-SNEDDS failed to bypass first-pass metabolism and therefore showed compromised oral absorption enhancement. The present study could promote the development of more efficient oral formulations of Morin with optimized absorption enhancement.

Gelsenicine is an indole alkaloid isolated from Gelsemium elegans Benth. In recent years, the role of G. elegans Benth preparations in anti-tumor, analgesic, dilatation and dermatological treatment has attracted attention, and it has been applied clinically, but it is easy to cause poisoning with its use. An UPLC-MS/MS method was established to determine the gelsenicine in mouse blood, and the pharmacokinetics of gelsenicine after intravenous (0.1 mg/kg) and intragastric (0.5 and 1 mg/kg) administration was studied. Deltalin was used as internal standard; a UPLC BEH C18 column was used for chromatographic separation. The mobile phase consisted of acetonitrile and 10 mmol/L ammonium acetate (0.1% formic acid) with a gradient elution flow rate of 0.4 mL/min. Multiple reaction monitoring mode was used for quantitative analysis of gelsenicine in electrospray ionization positive interface. Proteins from mouse blood were removed by acetonitrile precipitation. A validation of this method was performed in accordance with the US Food and Drug Administration guidelines. In the concentration range of 0.05-100 ng/mL, the gelsenicine in the mouse blood was linear (r > 0.995), and the lower limit of quantification was 0.05 ng/mL. In the mouse blood, the intra-day precision RSD was 76.8%, and the matrix effect was between 103.7 and 108.4%, which meet the pharmacokinetic research requirements of gelsenicine. The UPLC-MS/MS method is sensitive, rapid and selective, and has been successfully applied to the pharmacokinetic study of gelsenicine in mice. The absolute bioavailability of gelsenicine is 1.13%.