Development of solid lipid nanoparticles containing total flavonoid extract from Dracocephalum moldavica L. and their therapeutic effect against myocardial ischemia-reperfusion injury in rats.

Total flavonoid extract from Dracocephalum moldavica L. (TFDM) contains effective components of D. moldavica L. that have myocardial protective function. However, the cardioprotection function of TFDM is undesirable due to its poor solubility. In order to improve the solubility and efficacy of TFDM, we developed TFDM-loaded solid lipid nanoparticles (TFDM-SLNs) and optimized the formulation of TFDM-SLNs using central composite design and response surface methodology. The physicochemical properties of TFDM-SLNs were characterized, and the pharmacodynamics was investigated using the myocardial ischemia-reperfusion injury model in rats. The nanoparticles of optimal formulation for TFDM-SLNs were spherical in shape with the average particle size of 104.83 nm and had a uniform size distribution with the polydispersity index value of 0.201. TFDM-SLNs also had a negative zeta potential of -28.7 mV to ensure the stability of the TFDM-SLNs emulsion system. The results of pharmacodynamics demonstrated that both TFDM and TFDM-SLN groups afforded myocardial protection, and the protective effect of TFDM-SLNs was significantly superior to that of TFDM alone, based on the infarct area, histopathological examination, cardiac enzyme levels and inflammatory factors in serum. Due to the optimal quality and the better myocardial protective effect, TFDM-SLNs are expected to become a safe and effective nanocarrier for the oral delivery of TFDM.

Improved Oral Bioavailability of Total Flavonoids of Dracocephalum moldavica via Composite Phospholipid Liposomes: Preparation, in-vitro Drug Release and Pharmacokinetics in Rats.

BACKGROUND: Dracocephalum moldavica L is a traditional Uygur medicine for centuries, total flavonoids extracted from Dracocephalum moldavica are the major active ingredients of herbs, which possesses significant medicinal values to treat coronart disease and hypertension, due to the glycosyl group on the ring, total flavonoids of Dracocephalum moldavica has low hydrophilic and poorly absorbed after oral administration, so one way is the formulation of poorly water soluble and permeabledrugs with lipids containing formulations such as Composite phospholipid liposomes to improve the absorption profile of drug. OBJECTIVES: To prepare composite phospholipid liposome (CPL) encapsulatetotal flavonoids extract from Dracocephalum moldavica (TFDM), determine its physicochemical properties, investigate its in-vitro release and evaluate the pharmacokinetics in Sprague-Dawley (SD) rats to increase the bioavailability of TFDM-CPL. MATERIAL AND METHODS: The TFDMCPL was prepared by the method of ammonium sulfate transmembrane gradients. The CPL and TFDM were separated by Sephadex-G50 chromatography. The concentration of TFDM in the CPL was detected by HPLC, then the entrapment efficiency (EE) was evaluated. And the shape, particle size, zeta potential, drug release in vitro of TFDMCPL were investigated, and the pharmacokinetics was evaluated by rat jugular vein intubation tube in SD rats. RESULTS: The EE of TFDM was 84.17±2.2%, mean size of TFDMCPL was 136.2±3.7nm, polymey disperse index (PDI) was 0.158±0.015 and zeta potential was -19.8±1.2mV. TFDM-CPLwere found to enhance the release of drugs more effectively than TFDM based on the in vitro model and Following oral administration of TFDM, the plasma exposures of TFDM-CPL was significantly extended, and the mean concentration of TFDM-CPL was significantly higher compared to TFDM-solution. TheCmax, t1/2, AUC0-12 h values of TFDM for group of TFDM-CPL were siginificantly increased. CONCLUSION: The method of ammonium sulfate transmembrane gradients is suitable for preparingTFDM-CPL. And TFDM-CPL have potential to be used to improve the bioavailability of poorly soluble drugs after oral administration. SUMMARY: For the first time, composite phospholipid liposomes (CPL) containing total flavonoids of Dracocephalum moldavica (TFDM) were developed by method of ammonium sulfate transmembrane gradients.The TFDM-CPL was a significant improvement in bioavailability compared to the TFDM-solution, with a 10-fold increase in relative bioavailability in vivo.The TFDM-CPL was still stable during storage at 4oC for 6 months. Abbreviations Used: CPL: composite phospholipid liposome.; TFDM: Total Flavonoids Extract from Dracocephalum moldavica; SD:Sprague-Dawley; EE:entrapment efficiency; PDI: polymey disperse index; TFDM-CPL: Total flavonoid extract from Dracocephalum moldavica - composite phospholipid liposome; DM: Dracocephalum moldavica L.; SPC: Soybean phospholipid; HSPC: Hydrogenated soya phosphatide; PBS: phosphate buffered saline; HPLC: high performance liquid chromatography; TEM: transmission electron microscopy; CMC-Na: Carboxy Methyl Cellulose-Natrium; AUC: area under the curve.

Optimization of the process variables of tilianin-loaded composite phospholipid liposomes based on response surface-central composite design and pharmacokinetic study.

Tilianin is attracting considerable attention because of its antihypertensive, anti-atherogenic and anticonvulsive efficacy. However, tilianin has poor oral bioavailability. Thus, to improve the oral bioavailability of tilianin, composite phospholipid liposomes were adopted in this work as a novel nanoformulation. The aim was to develop and formulate tilianin composite phospholipid liposomes (TCPLs) through ethanol injection and to apply the response surface-central composite design to optimize the tilianin composite phospholipid liposome formulation. The independent variables were the amount of phospholipids (X1), amount of cholesterol (X2) and weight ratio of phospholipid to drug (X3); the depended variables were particle size (Y1) and encapsulation efficiency (EE) (Y2) of TCPLs. Results indicated that the optimum preparation conditions were as follows: phospholipid amount, 500 mg, cholesterol amount, 50mg and phospholipid/drug ratio, 25. These variables were also the major contributing variables for particle size (101.4 ± 6.1 nm), higher EE (90.28% ± 1.36%), zeta potential (-18.3 ± 2.6 mV) and PDI (0.122 ± 0.027). Subsequently, differential scanning calorimetry techniques were used to investigate the molecular interaction in TCPLs, and the in vitro drug release of tilianin and TCPLs was investigated by the second method of dissolution in the Chinese Pharmacopoeia (Edition 2015). Furthermore, pharmacokinetics in Sprague Dawley rats was evaluated using a rat jugular vein intubation tube. Results demonstrated that the Cmax of TCPLs became 5.7 times higher than that of tilianin solution and that the area under the curve of TCPLs became about 4.6-fold higher than that of tilianin solution. Overall, our results suggested that the prepared tilianin composite phospholipid liposome formulations could be used to improve the bioavailability of tilianin after oral administration.