Pharmacokinetic comparisons of single herb extract of Fufang Danshen preparation with different combinations of its constituent herbs in rats.

Salvianolic acid B (SAB), tanshinone IIA (TS), ginsenoside Rb1 (Rb1), ginsenoside Rg1 (Rg1) and notoginsenoside R1 (R1) are major active ingredients of Fufang Danshen preparation (FDP) for its protective effects on myocardial ischemia. This study investigated the pharmacokinetics of marker compounds after oral administration of single herb extract and different combinations of constitutional herbs in FDP, and explored potential herb-herb interactions among the ingredients in the multi-herb medicine. The pharmacokinetics study on the target compounds in rat plasma was performed using an optimal ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) coupled with protein precipitation method. There were no statistically significant differences in pharmacokinetic parameters of SAB, TS, Rb1, Rg1 and R1 between single Radix Salvia miltiorrhiza (S. miltiorrhiza) or Radix Panax notoginsen (P. notoginseng) extract and combination treatment. While, in comparison with oral administration of P. notoginseng extract alone, the pharmacokinetic parameters (C(max), AUC(0-72 h), AUC(0-∞), Cl, V), particularly for Rb1 and Rg1, were significantly different after oral administration P. notoginseng extract with addition of borneol (p<0.05). The AUC(0-72 h) values of Rb1 and Rg1 were significantly increased 1.3-fold and 1.6-fold, respectively, after P. Notoginsen extract co-administered with borneol. The results showed that herb-herb interactions may be accounting for the different pharmacokinetic behaviors of active constituents administered in compound prescriptions versus in single-herb extracts, however, which were not significant in most cases.

Improved dissolution rate and bioavailability of fenofibrate pellets prepared by wet-milled-drug layering.

OBJECTIVE: The objective of this study is to investigate the wet-milled-drug layering process which could significantly improve the dissolution rate and oral bioavailability of fenofibrate pellets. METHODS: Fenofibrate was milled with HPMC-E5 to prepare a uniform suspension in the micrometer and nanometer range, and this suspension was then layered on to sugar spheres to form the pellets (F1, F2). RESULTS: The particle size was significantly reduced (from 1000 µm to 1-10 µm and 400 nm) but the fenofibrate in suspension retained its crystallinity from the results of DSC and PXRD investigations. The dissolution rate of F1-F2 and Antara® capsules was 55.47 %, 61.27 % and 58.43 %, respectively, in 0.01 mol/L SDS solution over 60 min. In addition, F1, F2, and Antara® capsules were given orally to 6 beagle dogs to determine the bioavailability. The C(max) of F1, F2 (8.21 ± 2.55 and 9.33 ± 2.37 µg/mL)and the AUC((0-t)) of F1, F2 (152.46 ± 78.89 and 172.17 ± 67.58 µg/mL·h)were higher than those of Antara® (6.02 ± 3.34 µg/mL and 89.82 ± 46.46 µg/mL·h) and, F1, F2 reached their C(max) earlier than Antara® (F1: 2.0 ± 1.1 h; F2: 1.8 ± 1.2 h; Antara®: 6.0 ± 8.9 h). CONCLUSION: These results show that the wet-milled-drug layering technique is a powerful method to improve the dissolution rate and the bioavailability of fenofibrate.

Enhancing effects of chitosan and chitosan hydrochloride on intestinal absorption of berberine in rats.

Berberine chloride (BBR) is a plant alkaloid that has been used for centuries for treatment of inflammation, dysentery, and liver diseases. It is poorly absorbed from the gastrointestinal (GI) tract and its various clinical uses are limited because of its poor bioavailability. The object of the present study was to investigate the absorption enhancing effect of chitosan on BBR. Mixtures of BBR and chitosan were prepared and the absorption enhancement was investigated in rats. The results showed a dose-dependent absorption enhancement produced by chitosan. Formulations containing 0.5%, 1.5%, and 3.0% chitosan resulted in improvement of AUC(0-36 h) values by 1.9, 2.2, 2.5 times. The absorption enhancing ability of chitosan may be due to its ability to improve the BBR paracellular pathway in the intestinal tract. Chitosan hydrochloride, a salt of chitosan, was also investigated in this study. However, the addition of 2.0% and 3.3% chitosan hydrochloride to BBR solution did not produce any increase in either C(max) or AUC(0-36 h) of BBR. Subsequent solubility studies suggested that the reduced berberine chloride solubility in chitosan hydrochloride may limit the enhancement ability. This study showed that the optimum formulation producing the highest BBR absorption is the BBR solution containing 3.0% chitosan.

Bioavailability study of berberine and the enhancing effects of TPGS on intestinal absorption in rats.

Berberine chloride (BBR) is a natural isoquinoline alkaloid extracted from medicinal herbs. It has been reported that the intestinal absorption of BBR is very low. In this study, the absolute bioavailability of BBR was studied, and the enhancing effects of D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) on intestinal absorption were investigated in rats. BBR injection was administrated via the femoral vein at a dose of 1.0 mg kg(-1) in intravenous group, and BBR oral formulations were administrated by oral gavage at a dose of 100 mg kg(-1) in BBR control (control) group and BBR-TPGS (test) group, respectively. The result showed that BBR had a very low absolute bioavailability of 0.68%, and TPGS could enhance intestinal absorption of BBR significantly. TPGS at a concentration of 2.5% could improve peak concentration (C(max)) and area under the curve (AUC(0-36)) of BBR by 2.9 and 1.9 times, respectively. The absorption enhancing ability of TPGS may be due to its ability to affect the biological activity of P-glycoprotein and thereby reduce the excretion of absorbed BBR into the intestinal lumen. This study indicated that absolute bioavailability of BBR was 0.68% in rats, and TPGS was a good absorption enhancer capable of enhancing intestinal absorption of BBR significantly.

Injectable nimodipine-loaded nanoliposomes: preparation, lyophilization and characteristics.

The main purpose of this study was to prepare nimodipine-loaded nanoliposomes for injection and evaluate their characteristics after lyophilization. Nimodipine-loaded nanoliposomes were prepared by the emulsion-ultrasonic method with sodium cholesterol sulfate (SCS) as the regulator and then lyophilized by adding different cryoprotectants. SCS was used as a blender of regulator and surfactant and helped to prepare smaller liposomes due to the steric hindrance of the sulfate group. The results showed that nimodipine-loaded nanoliposomes with a 20:1 of egg yolk lecithin PL-100M vs. SCS ratio had a particle size of 86.8±42.007 nm, a zeta potential of -13.94 mV and an entrapment efficiency (EE) of 94.34% and could be stored for 12 days at 25°C. Because of the good bulking effect of mannitol and the preservative effect of trehalose, they were used to obtain suitable lyophilized nanoliposomes. The lyophiles containing 10% mannitol and 20% trehalose had a good appearance and a slightly altered particle size after rehydration. In addition, the lyophilized products were characterized by differential scanning calorimetry, X-ray diffraction and scanning electron microscopy, which confirmed the morphous state of trehalose, mannitol and the mixture. Trehalose could inhibit mannitol crystallization to some extent. The drug release from nanoliposomes before and after lyophilization in pH 7.4 phosphate buffer containing 30% ethanol was also examined and both profiles were found to fit the Viswanathan equation. This means that the drug release was controlled by the pore diffusion resistance.