Lipid-Based Nanocarriers Enabled Oral Delivery of Oleanolic Acid Derivative DKS26 for Diabetes Management.

Oleanolic acid derivative DKS26 has hypolipidemic, islet, and hepatoprotective effects. However, high lipophilicity and low water solubility led to DKS26 extremely low oral bioavailability. Herein, lipid-based nanocarriers, including lipid nanodiscs (sND/DKS26) and liposomes (sLip/DKS26), are prepared to improve DKS26 oral absorption. In comparison to free DKS26 (5.81%), the absolute oral bioavailabilities are significantly increased to 29.47% (sND/DKS26) and 37.25% (sLip/DKS26) without detectable toxicity or immunogenicity even after repeated administrations. Both sND/DKS26 and sLip/DKS26 significantly reduce the feeding glucose level and the AUC of OGTT in db/db diabetic mice. Aiding by the newly developed scFv-based nanocarrier separation methods, no intact nanocarriers are detected in blood circulation after oral administration, suggesting that both formulations are unable to penetrate the intestinal epithelium. They enhance DKS26 absorption mainly by improving intestinal cell uptake and rapid intracellular release of the payload. Since pre-existing anti-PEG is widely detected in humans, the present oral absorption pathway of both nanocarriers successfully avoids unfavorable immunological responses after interaction with anti-PEG antibodies. The application of lipid-based nanocarriers paves an efficient and safe avenue for the clinical translation and application of poorly soluble therapeutics derived from traditional Chinese medicine.

Pharmacokinetics, Tissue Distribution, and Excretion Study of Cajanonic Acid A in Rats by UPLC-MS/MS.

Cajanonic acid A (CAA), a prenylated stilbene derivative extracted from the leaves of pigeon pea (Cajanus cajan), has been reported to possess inhibitory activity on the peroxisome proliferator-activated receptor gamma (PPARγ) and protein tyrosine phosphatase 1B (PTP1B). Its hypoglycemic activity in rats is comparable to that of the approved antidiabetic agent rosiglitazone. Therefore, CAA is a potential candidate for the treatment of type 2 diabetes and a lead compound for the discovery of novel hypoglycemic drugs. To achieve a thorough understanding of the biological behavior of CAA in vivo, our current study was designed to investigate the pharmacokinetics, bioavailability, distribution, and excretion of CAA in rats by UPLC-MS/MS. Chromatographic separation was performed on BEHC18 column (2.1 mm × 50 mm, 1.7 µm). Quantification was performed under the negative ion mode by using single reaction monitoring (SRM) of the transitions of m/z 353.14 → 309.11 for CAA and m/z 269.86 → 224.11 for genistein, respectively. Standard calibration curve showed excellent linearity (r2 > 0.99) within the range of 2 - 800 ng/mL. The accuracies and precisions were within the acceptance limits (all < 20%). CAA was quickly absorbed into bloodstream and distributed rapidly and widely to various tissues. The excretion ratio of CAA in the 3 main pathways via bile, feces, and urine was only 5.17%. These results indicate that CAA was quickly and thoroughly metabolized in vivo and excreted mainly as metabolites.