Paclitaxel-Honokiol Nanocrystal Targeted Drug Delivery System Based On Multidrug Resistance

Objective:To study the effect of honokiol combined with paclitaxel on reversing multidrug resistance of tumor cells,and the two drugs were combined to prepare nanocrystals so that they can be released in proportion to the in vitro screening.Method:(1)The inhibitory effects of paclitaxel,honokiol and their combination on the growth of human lung cancer cell A549/T resistant to Taxol were assessed by MTT colorimetry;(2)CompuSyn.exe software was used to analyze the relationship between the two drugs,and the optimal synergy ratio between the two drugs was selected with the combined index(CI)as an indicator;(3)According to the optimal ratio of the two drugs screened in vitro,the anti-solvent precipitation method was used to prepare paclitaxel-and magnolol nanosuspension.Then it was lyophilized as nanococrystal with the coating of polydopamine(PDA)that further modified the surface of RGD-PEG-NH2.;(4)Differential scanning calorimetry(DSC),X-ray powder diffraction(PXRD),transmission electron microscopy(TEM),and Fourier transform infrared spectroscopy(FT-IR)were used to perform paclitaxel-honokiol nanocrystals characterization.In vitro release experiments were carried out with dialysis bag method to determine whether or not the two drugs were released according to the proportion selected by cell experiment.(5)The preparation was subjected to MTT experiment to verify the effect of the preparation on inhibiting the proliferation of A549/T cells after the two drugs were combined into nanocrystals.Result:(1)Paclitaxel and honokiol and the combination of both drugs could inhibit the growth of A549/T cells in a dose-dependent manner within a certain dose range.The effect of two drugs combined was stronger than that of paclitaxel or honokiol;(2)The calculation results of CompuSyn.exe software showed the relationship of paclitaxel and honokiol was additive effect or synergistic effect.The CI value was 0.7098,and the optimal ratio of paclitaxel and honokiol was 1:2;(3)PEGylated nanocrystals with RGD peptide modification(PTX-HNK@PDA-PEG-RGD)were prepared with the shape closed to a sphere.Their hydrodynamic diameters were 221.6±5.728 nm and the dispersion coefficient of PD I was 0.232.Moreover,the results of differential scanning calorimetry and X-ray powder diffraction showed that the paclitaxel-honokiol nanocrystals mainly existed in the amorphous form,and the Fourier transform infrared spectrum indicated that hydrogen bonds were formed between the two drugs.In vitro release experiments showed that the release trends of the two drugs were consistent,and there was a trend of proportional release.(4)Different nano-formulations can inhibit the proliferation of A549/T cells,and the inhibitory effect on A549/T cells is significantly enhanced after connecting RGD peptide.Conclusion:The above results show that paclitaxel and honokiol have synergistic effect and the prepared nanocrystals are characterized by their small size,concentrated distribution and good stability.A PDA platform is conducive to the further modification and can accelerate the release of drugs in acidic environment,and the two drugs have a tendency to be released in proportion to in vitro screening.After connecting the RGD peptide,the cytotoxicity of the preparation was significantly enhanced.All in all,this study shows the superiority of the nano drug delivery system based on the combination of the two drugs to reverse multi-drug resistance.In the system the two drugs have potential to reach tumor tissue in proportion in vitro screening.