Pharmacokinetics Comparison, Intestinal Absorption and Acute Toxicity Assessment of a Novel Water-Soluble Astragaloside IV Derivative (Astragalosidic Acid, LS-102).

BACKGROUND AND OBJECTIVES: Astragaloside IV (AGS IV) is the most important bioactive constituent of Radix Astragali. However, its disappointing clinical application is mainly caused by its very low solubility in biologic fluids, resulting in poor bioavailability after oral administration. We recently obtained a novel water-soluble derivative of AGS IV (astragalosidic acid, LS-102) that displayed significant cardioprotective potential against hypoxia-induced injury. The objective of this study was to investigate the intestinal absorption, main pharmacokinetic parameters and acute toxicity of LS-102 in rodents compared with AGS IV. METHODS: An oral dose of LS-102 and AGS IV (20 mg/kg) was administered to Sprague-Dawley (SD) rats, and blood samples were collected at predetermined time points. The plasma concentrations were detected by a validated UHPLC-MS/MS method, and pharmacokinetic parameters were calculated using a compartmental model. In the intestinal permeability study, the transport of LS-102 across Caco-2 cell monolayers was investigated at six concentrations from 6.25 to 250 µM. Moreover, the acute toxicity of LS-102 (40-5000 mg/kg) via a single oral administration was investigated in BALB/c mice. RESULTS: LS-102 was rapidly absorbed, attaining a maximum concentration of 248.7 ± 22.0 ng/ml at 1.0 ± 0.5 h after oral administration. The relative bioavailability of LS-102 was twice that of AGS IV. LS-102 had a Papp (mean) of 15.72-25.50 × 10-6 cm/s, which was almost 500-fold higher than that of AGS IV, showing that LS-102 had better transepithelial permeability and could be better absorbed in the intestinal tract. The acute toxicity study showed no abnormal changes or mortality in mice treated with LS-102 even at the single high dose of 5000 mg/kg body weight. CONCLUSIONS: Oral LS-102 produced a pharmacokinetic profile different from AGS IV with higher bioavailability, while the toxic tolerance was similar to previous estimates. Thus, we speculated that LS-102 might provide better clinical efficacy and be a potential candidate for the new drug development of Radix Astragali.

Determination of asperosaponin VI and its active metabolite hederagenin in rat tissues by LC-MS/MS: application to a tissue distribution study.

Two high-performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) mass spectrometry methods were developed and validated for the simultaneous determination of asperosaponin VI (A-VI) and hederagenin (HG) in rats' various tissues. Biological samples were processed with methanol extraction, and glycyrrhetinic acid was chosen as the internal standard (IS). The analytes were separated on a C18 column with two gradient elution programs for different rat tissue samples. The MS/MS detection was carried out by monitoring the transitions of m/z [MH](-) 927.5→603.4 for A-VI, m/z [MH](-) 471.3→471.3 for HG and m/z [MH](-) 469.4→425.4 for the IS, respectively. The lower limits of quantification (LLOQ) for the two analytes in different rat tissues were 2-6ng/mL, respectively. The methods were successfully applied to a tissue distribution study of A-VI and its active metabolite HG in rats. The results of the tissue distribution study showed that the highest concentration of A-VI was in the gastrointestinal (GI) tract. Besides, A-VI was mainly distributed in lung, liver, fat and ovary. HG was almost undetectable in most tissues except for the GI tract.

In vitro & in vivo assessment of a herbal formula used topically for bone fracture treatment.

AIM OF THE STUDY: A novel topical paste used for fracture healing (FH), consisting of the extracts of six herbs, Radix Dipsaci, Ramulus Sambucus Williamsii, Rhizoma Notoginseng, Flos Carthami, Rhizoma Rhei and Fructus Gardeniae, was developed according to the classical theory of traditional Chinese medicine. This study aimed to determine the effectiveness of this formula, and some of its important chemical components in the promotion of fracture healing. The transdermal transport of FH was also examined. MATERIALS AND METHODS: The osteogenic, angiogenic and nitric oxide suppressing effects of FH and its important chemical marker components were assessed by using osteoblastosacroma UMR-106 cells, human umbilical vein endothelial cells (HUVEC) and murine macrophage RAW264.7 cells, respectively. The bone healing effects of the FH paste and its transdermal absorption were determined using a rabbit fracture model. The callus sizes, bone specific alkaline phosphatase levels and biomechanical properties of the healed bone were assessed. RESULTS: FH significantly increased the cell proliferation in UMR-106 and HUVEC cells and inhibited the nitric oxide production in murine macrophage in dose-dependent manner. Its important chemical components asperosaponin VI, ginsenoside Rg1 and emodin were shown to be acting positively in the respective in vitro studies. FH paste significantly improved the bone healing in the rabbit fracture model, as was indicated by the increases in callus size at weeks 2-5, and the elevations in bone specific alkaline phosphatase activities at weeks 5-6. The analysis using LC/MS/MS also showed the presence of important chemical marker components of the FH formula in the plasma after 8 weeks of topical treatment. CONCLUSION: This study presents the first scientific evidence of the efficacy of a herbal paste in the promotion of fracture healing. There were evidences of transdermal transport of the chemical components, control the inflammation through nitric oxide inhibition, promotion of angiogenesis, and bone healing in the in vitro tests, as well as in the experimental animal.

The assessment of absorption of periplocin in situ via intestinal perfusion of rats by HPLC.

Periplocin is an important compound of Cortex Periplocae, which shows poor absorption when administered orally. The effective intestinal permeability of periplocin was investigated using single-pass intestinal perfusion technique in male Wistar rats. SPIP was performed in rat jejunum. The samples of perfusate were collected at the designated time points after rat intestinal perfusion and analyzed by HPLC. The specificity of this method was demonstrated by the absence of interference of the drug peak with the intestinal sac artifacts and the components of the KRB solution. Recovery studies, as well as the intra-day and inter-day variations, were within statistical limits. This technique was applied to the study of the intestinal absorption of periplocin. The determined fraction absorbed (F(a)) of periplocin was 0.151 +/- 0.072 (n = 6) at a concentration of 6 microg/mL; the absorption rate constant (K(a)) was 0.0102 +/- 0.0039/min and the effective permeability coefficient (P(eff)) was 0.0021 +/- 0.0012 cm/min. These data suggest that periplocin has high permeability and might be absorbed in rat intestine.