Study On The Treatment Of Lung Cancer With Doxorubicin Hydrochloride Inhaled Porous PLGA/PCADK Microspheres

Lung cancer is one of the most common malignant tumors,and morbidity and mortality are rising year by year,which seriously threatens human health.Chemotherapy is still one of the main treatments for lung cancer.It is usually administered by oral or intravenous injection.However,there are corresponding disadvantages in both modes of administration.For example,oral administration can stimulate the stomach and the bioavailability of the drug is low.Intravenous administration requires a large dose and causes large systemic side effects,so it is particularly important to explore new modes of administration for lung cancer treatment.In recent years,inhaled lung targeted drug delivery has attracted widespread attention among researchers.Because the drug that reaches the lungs through the trachea can directly penetrate into the lung tissue or blood vessels to exert a corresponding therapeutic effect,which can significantly reduce the dosage and increase the local effective drug concentration in the lung.Pulmonary administration can reduce systemic toxic side effects while ensuring anti-tumor effects.At present,PLGA porous microspheres is a important dosage form for researchers in the treatment of lung cancer through inhaled pulmonary targeted drug delivery,but these microspheres often fail to achieve the desired tumor treatment effect due to incomplete drug release.Polyketal(PCADK)is a new polymer material that is acid-sensitive,biodegradable,non-toxic and non-irritating.In order to solve the problem of incomplete release of PLGA sustained-release microspheres by injection,researchers have prepared PLGA / PCADK hybrid microspheres and found that the drug release of PLGA / PCADK solid mixed microspheres is faster and more complete than PLGA microspheres.Therefore,this study proposes the combination of PLGA / PCADK hybrid microspheres and pulmonary inhalation therapy to construct an inhaled PLGA /PCADK porous hybrid microsphere delivery system containing doxorubicin hydrochloride to treat non-small cell lung cancer.The research work of this topic can be summarized as the following three aspects:(1)In this paper,PLGA / PCADK porous hybrid microspheres with different mixing ratios were successfully prepared by using ammonium bicarbonate as porogen and W/O/W emulsion solvent evaporation method.In order to obtain a microsphere delivery system with high drug loading,high encapsulation efficiency,good uniformityand good drug release performance,we screened the factors affecting the physical and chemical properties of PLGA / PCADK porous hybrid microspheres by single quantitative method,including PLGA / PCADK mixing ratio,porogen dosage and double emulsion speed.The results show that when the PLGA / PCADK mixing ratio is 8/2,the porogen concentration is 5 mg / ml,and the double emulsion speed is 10000 rpm,the microspheres have good uniformity,obvious porous morphology,good aerodynamic diameter(2.72 ± 0.20 ?m)and high encapsulation efficiency(69.41 ±11.98%).We have studied the release behavior of PLGA / PCADK(8/2)porous mixed microspheres,and the results show that in different conditions of phosphate buffer,the total release of doxorubicin hydrochloride in PLGA / PCADK(8/2)porous microspheres was 41.88 ± 1.44%(pH 7.4)and 65.11 ± 2.49%(pH 5.0),which is better than PLGA porous microspheres 34.55 ± 1.10%(pH 7.4)and 46.33 ± 5.72%(pH 5.0).This result indicates that the material degradation and drug release of PLGA / PCADK(8/2)porous hybrid microspheres are faster and more complete than PLGA porous microspheres.Due to the acid sensitivity of PCADK,the difference in degradation and drug release between the two microspheres is more pronounced with decreasing pH.(2)After comparing the physicochemical properties of PLGA porous microspheres and PLGA / PCADK(8/2)porous hybrid microspheres,we explored their in vitro efficacy.First,MTT assay was used to detect the inhibitory effect of PLGA / PCADK(8/2)porous hybrid microspheres on the proliferation of A549 cells.It was found that PLGA / PCADK(8/2)porous hybrid microspheres had stronger inhibitory effect on cell proliferation in vitro than PLGA porous microspheres.Subsequently,two microsphere-induced apoptosis and cycle arrest of A549 cells were detected by flow cytometry.The results showed that PLGA / PCADK(8/2)porous microspheres had stronger apoptosis-inducing effect and G2 phase arrest on A549 cells than PLGA porous microspheres.In addition,the anti-tumor proliferation mechanism of PLGA /PCADK(8/2)porous hybrid microspheres and PLGA porous microspheres was investigated by Western blotting and Enzyme-Linked ImmunoSorbent Assay.It was found that the release of both microspheres promoted the expression of the apoptotic proteins Bax,Bad and Caspase-3,8,9 and enhanced the protein activity of Caspase-3,8,9.At the same time,the expression of anti-apoptotic proteins Bcl-2 and Bcl-xl was inhibited,and the effect of PLGA / PCADK(8/2)porous mixed microspheres was stronger than that of PLGA porous microspheres.(3)In vivo and in vitro lung deposition of PLGA / PCADK porous microspheresand PLGA porous microspheres were investigated.The emptying rate and in vitro deposition efficiency of the two kinds of microspheres were measured by a Two Stage Impactor.The results showed that the powder emptying rate of PLGA / PCADK(8/2)porous mixed microspheres was 95.7%,and the in vitro deposition rate was 40.1%.The powder emptying rate of PLGA porous hybrid microspheres was 93.4%,the in vitro deposition rate was 37.2%.We can know that the two microspheres have similar powder emptying rate and in vitro deposition rate;.In addition,PLGA porous microspheres and PLGA / PCADK porous microspheres both loaded with DiR fluorescent dye were used for pulmonary administration of SD rats by dry powder spray pulmonary administration device,The Optical in Vivo Imaging was used to observe the deposition of microspheres in the lungs.The results showed that both microspheres have good inhalability and can be targeted to the lungs via the trachea.The above studies show that PLGA / PCADK(8/2)porous mixed microspheres are superior to PLGA porous microspheres in drug release and antitumor efficiency.And PLGA / PCADK(8/2)porous mixed microspheres have a good potential for lung cancer treatment by pulmonary inhalation.