ABSTRACT
The films of vinylidene fluoride and trifluoroethylene (P(VDF-TrFE)) are widely used in piezoelectric tactile sensors, vibration energy harvesters, optical frequency conversion materials and organic photo-voltaic devices because of high electroactive, good optical and nonlinear optical properties, respectively. In this work, the multilayer structured ultrathin films were fabricated by the Langmuir-Blodgett technique, and the thickness per layer can be controlled accurately. It was found that as the collapse pressure of P(VDF-TrFE) (25:75) and the optimal dipping value are 60~70 mN/m and 15 mN/m, respectively, a high-density film can be obtained due to the compression of molecules. The surface topography and optical properties of the LB films were characterized by X-ray diffraction, white light interferometer and variable-angle spectrum ellipsometer. It was observed that the films are transparent in the visible region and IR-band, but show a high absorption in the UV band. Besides, the transmittance of the films ranges from 50% to 85% in the visible region, and it linearly decreases with the number of monolayers. The average thickness of per deposition layer is 2.447 nm, 2.688 nm and 2.072 nm, respectively, under three measurement methods. The calculated refractive index ranged from 1.443 to 1.598 (600~650 nm) by the Cauchy-model.
ABSTRACT
BACKGROUND: The active ingredients of Ganershu compound recipe, which are effective for hepatitis treatment in liver protection and transaminase reduction. However, the active ingredients of Ganershu compound recipe are poor absorption, which conduct it has a low oral bioavailability. OBJECTIVE: We prepared Ganershu sustained-release pellets (GSPs) by fluidized-bed on central composite design-response surface methodology and increase its bioavailability in beagle dogs. MATERIALS AND METHODS: In this study, GSPs were successfully prepared. The Drug-loaded pellets and sustained-release coated were carried out in fluidized-bed machine. GSP was optimized for fitting release, roundness, and the overall desirability by central composite design-response surface methodology. RESULTS: To optimize cumulative release profile, the outermost ethyl cellulose coating layer and the hydroxypropyl methyl cellulose (HPMC) swelling layer were employed, which were respectively given coating levels in terms of weight gain of 22% and 6%, the concentration of HPMC is 4.5% (g/ml). The pharmacokinetics of Ganershu normal pellets (GNPs) and GSP was studied in beagle dogs after oral administration. The naringenin as an index, the area under the curve0-∞ of naringenin in GSP was 1.38 times greater than that of GNP. Meanwhile, Tmax of GSP was prolonged for about 74%. CONCLUSION: This study can clearly indicate that we enhanced the oral bioavailability of Ganershu by preparing the GSP, which had the sustained dissolution and improved the potential of it for clinical application.
ABSTRACT
OBJECTIVE: To establish the fingerprint analysis method of Ganershu intermediate by HPLC. METHODS: An analysis was performed on a sunFire C18 (4. 6 mm x 250 mm, 5 microm) column with acetonitrile-0.1% phosphate aqueous as the mobile phase by gradient elution. The flow rate was 1.0 mL/min, the detection wavelength was 320 nm and detection time was 80 min. The column temperature was 35 degrees C. In the recorded chromatogram of Ganershu intermediate, neohesperidin was used as reference substance, and RSD of the relative retention time and the relative peak areas of all peaks compared with its peak were measured. The similarity of 10 batches of Ganershu intermediate was appraised by the similarity evaluation system. Using the external standard method, the contents of chlorogenic acid, neohesperidin and naringin were determined in 10 batches of intermediate. RESULTS: Tweenty-three peaks were separated on HPLC fingerprint in Ganershu intermediate, degree of similarity of fingerprint for ten batches of Ganershu intermediate were greater than 0.90. Three compounds' contents were almost the same in each batch of intermediate sample. CONCLUSION: The method is stable, accurate, reliable and can be used as a quality control for Ganershu intermediate and sustained-release capsules.
