| In recent years, polymeric micelles have attracted much interest as promising anticancer drug carriers due to their significances in reducing side effects, enhancing solubility, prolonging blood circulation time, and escaping capture from reticuloendothelial cell system.The diterpene lactones of Andrographis paniculata had anti-tumor effect. With the adoption of supermolecular technology, We could prepare the effective parts of Andrographis paniculata. The total content of diterpene lactones in the AEP such as andrographolide, ehydrated andrographolide and14-Deoxy-andrographolide is above 50%. However, poor water solubility and oral bioavailability of the effective parts of Andrographis paniculata has limited its clinical application. So, the construction of targeted drug delivery system is of great significance for improving the targeting property and bioavailability of drugs.With the catalysis of DMAP added,the mPEG2000-SOLM was prepared by the esterification of mPEG2000 and Semi ester of Solanesol- maleic anhydride( SOLM)which was prepared by esterification of Solanesol and Maleic anhydride. The structure and molecular weight of final products were confirmed with IR,1H-NMR and GPC spectra. The CMC of the polymer that was measured by means of pyrene fluorescence probe was 4.74×10-3 mg/mL.With the solvent evaporation method, Andrographolide, Dehydrated andrographolide,14-Deoxy-andrographolide and the effective parts of Andrographis paniculata was encapsulated by mPEG2000-SOLM separately. Then, we determined the particle size and morphology of micelles by DLS and TEM. The drug loading capacity and entrapping efficiency of A, DA and DDA micelles were(8.03±3.20)%?(2.7±0.50)%?(2.11±0.10)% and(55.72±12.30)%?(18.0±7.70)%?(17.1±10.40)%separately. Besides, the particle size of A, DA and DDA micelles were(138.6±18.6)nm?(96.97±53.26)nm ?( 226.2±2.80) nm separately and the dispersion is not uniform. The drug loading capacity and entrapping efficiency of AEP micelles were(34.07±1.14)% and(91.44±3.59)%, in addition, the drug loading capacity and entrapping efficiency of A, DA, DDA in AEP micelles were(28.73±1.29)%?(5.58± 0.27)%?(5.17±0.29)% and(93.50±4.87)%?(80.44±3.87)%?(90.16±5.17)% separately. We also found that the proportion of A, DA and DDA in AEP micelles was similar with free AEP. The AEP micelles were characterized by TEM with the particle size of(108.6±3.90) nm, good dispersity,spherical morphology and core-shell structure.The stability of mPEG2000-SOLM-AEP was investigated by several aspects. In the condition of-4?, and the particle size of micellar solution had no obvious change in 30 days without precipitation. The micellar solution were added with the same volume of PBS buffer(including 1.8% Nacl), 400 U of heparin and bovine serum albumin(final concentration of 0.1 mg/mL) and then oscillated under the conditions of37? and 120 r/min, the particle size of micellar solution had no obvious change without precipitation after5 h. DSC and X-RD analysis was carried out on the micelle, results showed that medication may be through amorphous form being entrapped in the micellar core. In vitro release studies showed that mPEG2000- SOLM- AEP micelles had burst release phenomenon and the release curve fitted first order kinetic equation. Besides, there was no obvious change in its release properties in release medium with different ionic strength and release properties of different components in the AEP were uniform.MTT method was used to investigate the inhibition of blank micelles, AEP and mPEG2000-SOLM-AEP micelles on human breast cancer cells MCF-7 and human lung cancer cells A549.After 48 h, the blank micelles had no significant inhibitory effect on the two kinds of cells; for mPEG2000-SOLM-AEP micelles, the IC50 values of two kinds of cells were 15.47 ?g/mL and 13.32 ?g/mL;but for free AEP, the IC50 values of two kinds of cells were 28.90 ?g/mL and 36.56 ?g/mL. The results showed that drug loaded micelles had stronger inhibitory effects than free AEP.The pharmacokinetics of mPEG2000-SOLM-AEP and free AEP in rats were studied. HPLC method was developed to detect plasma drugconcentration of A and DDA in rats and the methodology was also inspected. The experimental animal were randomly divided into preparation group and free AEP group by i.v. in rat tail. The measured data were calculated using DAS 2.0 software. The pharmacokinetics of drugs of two groups in rats were consistent with the two compartment model. For A, the drug dosage of preparation group and free AEP group were 5.32 mg/kg and 24.28 mg/kg, the A of free AEP group could not be detected after 5 h of administration, while, the A of preparation group could be detected after 24 h of administration. the CL of A in free AEP group(9482.263 L/h/kg) was much higher than the preparationgroup(814.858 L/h/kg). After dose correction, the AUC(0-t) of A in the preparation group is 6.7 times of the free AEP group. For DDA, the drug dosage of preparation group and free AEP group were 1.32 mg/kg and 5.90 mg/kg. The DDA of the two groups began to increase at 1h after administration, reached the peak at about 5h, and then began to eliminate. The CL of DDA in free AEP group(682.916 L/h/kg) was higher than the preparation group(239.428 L/h/kg). After dose correction, the AUC(0-t) of DDA in preparation group is 3.5 times of the free AEP group. The results showed the AEP drug loaded micelles could protect the drug from being identified and eliminated by in vivo scavenging system, prolong the circulation time in vivo, and significantly increase the AUC(0-t) of drug. Mainwhile, this provide theoretical basis for the study of the pharmacodynamics of AEP drug loaded micelles in vivo. |
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