ABSTRACT
Objective:To investigate the relationship between phase behavior of curcumin （CUR） from self-nanoemulsion drug delivery system （SNEDDS） and stability of the formed nanoemulsion in artificial gastrointestinal fluid. Method:The growth rate of precipitation after dispersion of CUR-SNEDDS was expressed by the change tendency of CUR supersaturation-time curve. The effect of drug loading on crystal nucleation and growth was investigated by ultraviolet-visible spectrometry and polarized light microscope， respectively. X-ray powder diffraction （XRD） and differential scanning calorimetry （DSC） were used to analyze the precipitation forms of CUR-SNEDDS with different drug loading in artificial gastrointestinal fluid. At the same time， the effect of drug loading on the quality stability of nanoemulsion formed by CUR-SNEDDS in artificial gastrointestinal fluid was investigated. Result:In the artificial gastrointestinal fluid， with the increase of drug loading， the area under the supersaturation-time curve of CUR was increased （100% drug loading≈90% drug loading>75% drug loading）， the crystallization nucleation and growth rate were accelerated （100% drug loading>90% drug loading>75% drug loading）， the amorphous proportion in the precipitation composition decreased， the nanoemulsion droplets adhered and distributed unevenly， the particle size and dispersivity were increased. Conclusion:High drug loading promotes the nucleation and growth of crystals， and increases the proportion of crystal forms in the precipitation composition， which leads to the decrease in the stability of the formed nanoemulsion. Therefore， it is suggested that the drug loading of CUR-SNEDDS needs to be controlled below 90%.
ABSTRACT
Objective:The phase separation of Baihutang was carried out. The content of mangiferin，new mangiferin，calciumion，glycyrrhizin and ammonium glycyrrhizinate in the solution phase，the nano phase and the precipitated phase of Baihutang were measured，so as to define the effect of nanometer particles of Baihutang on the growth of active components，and explain the mechanisms of Baihutang in potent detoxification and heat removal. Method:The phase separation of Baihutang was performed by high-speed centrifugation and dialysis. The contents of mangiferin，new mangiferin，glycyrrhizin and ammonium glycyrrhizinate in Baihutang were determined by HPLC. Chromatographic column Diamonsil C18 (4.6 mm×250 mm，5 μm) was adopted, with acetonitrile-25 mmol·L-1 potassium dihydrogen phosphate solution as the mobile phase, and eluted in a gradient mode. The detection wavelength was 257 nm，the column temperature was 30 ℃，and the flow rate was 1.0 mL·min-1. EDTA-2Na solution was used to calibrate the calcium concentration in different phase states of Baihutang. Result:1 mL Baihutang nanoparticles contained 483.00 μg new mangiferin，1 068.88 μg mangiferin，219.93 μg glycyrrhizin and 187.10 μg ammonium glycyrrhizin，and the content of new mangiferin and mangiferin accounted for 89.4% and 89.9% respectively in 1 mL Baihutang. The new mangiferin and mangiferin in the nano phase were 230.0 and 23.3 times the true solution，and 8.5 and 14.4 times of the precipitation，respectively. The content of calcium ions in Baihutang in the nano phase was higher，accounting for 86.9% of Baihutang，and the content of calcium ions in Baihutang and Baihutang in the nano phase was higher than that in gypsum group. Conclusion:The content of main components in Baihutang in nanometer phase is significantly higher than that in other phases. The nanoparticles of Baihutang have a solubilizing effect on the main antipyretic components, such as mangiferin，mangiferin and calcium ions as well as the antitoxic components glycyrrhizic acid and glycyrrhizic acid. The mechanism of action of Baihutang is related to the formation of nanoparticles.
ABSTRACT
This study aimed to investigate phase behaviors, to study effects of cosolvent addition on size of microemulsion regions and to propose modified logistic regression which could describe microemulsion regions in nonionic systems. The systems composed of rice bran oil (RBO) or isopropyl palmitate (IPP), various ratios of sorbitan monooleate (SMO) and polyoxyethylene 20 sorbitan monooleate (PSMO) mixtures, water and isopropyl alcohol (IPA) or propylene glycol (PG) were studied for their microemulsion regions obtained on the phase diagrams. Concept of modified logistic regression was used to predict probability of microemulsion formation and size of microemulsion regions in the systems. It was found that both oil and cosolvent types affected on microemulsion formation. A system composed of IPP, 2:1 water:IPA, and 1:1 SMO:PSMO could provide the largest microemulsion region. However, the purposed modified logistic regression could be used consistently for only one system of the total four systems due to the faceted shape of microemulsion-zone.