| Disulfiram（DSF）suffers from multiple shortcomings of poor aqueous solubility and instability in the physiological environment,which often hinder its clinical applicability.Moreover,as a copper-dependent antitumor drug,the limited availability of copper in the body also hampered the therapeutic ability of DSF.In an attempt to solve these problems,a variety of different forms of DSF-based delivery systems are prepared to substantially improve the antitumor effect of DSF.In a case,to improve the dissolution rate and subsequent therapeutic efficacy of DSF,the experimental solubility of DSF in supercritical carbon dioxide（SC-CO2）is initially determined and subsequently correlated using various empirical models.The solubility of DSF SC-CO2 is in a range from 7.89×10-55 to 6.71×10-4 mole fraction.Then,the sub-micronized products of DSF and its subsequent DSF-copper complexes（CuET）are fabricated using the rapid expansion of supercritical solutions（RESS）process.Further,the suspension ability of these complexes is improved by coating with polyvinylpyrrolidone（PVP）and methoxy b-poly（L-lactide）-poly（ethylene glycol）（mPLLA-PEG）solution using the RESS-based processes that with the different receiving mediums.The fabricated DSF and CuET particles are systematically characterized using a variety of physical characterization methods for determining the morphology,changes in the chemical structure,crystallinity,and dissolution rate in vitro.The average particle size of RESS process-assisted DSF decreased drastically.At the same time,the addition of polymer could obviously improve the dispersibility and dissolution rate of particles.After adding copper ions,CuET particles can be successfully prepared.Finally,the cytotoxicity of SCF-assisted DSF particles and their effects in the presence of copper are determined.In vitro anti-proliferation studies confirmed the substantial augmentation of bioefficacy of micronized DSF in the presence of copper.Moreover,the polymer-coated DSF or CuET nanoparticles significantly enhanced the toxicity of DSF,attributing to their relatively smaller sizes and excellent dispersibility in the aqueous environment.Thus,our findings showed that the altered dissolution rate of drugs and the synergistic effect of the metal species in CuET complex significantly amplified the antitumor efficacy of DSF,indicating the potential of RESS process in enhancing the dissolution rate as well as substantial antitumor efficiency of nano-sized drugs and their complexes.In another case,to solve the problems of low drug loading and low copper ion delivery efficiency of the existing DSF drug delivery system,according to the solubility of DSF in SC-CO2,DSF is loaded into the mesoporous silica nanoparticles（MSN）by supercritical solution impregnation（SSI）process.Initially,a factorial experiment was designed for investigating the relative significance of various processing parameters and achieving better control over drug loading,and the nano-delivery system for high-efficiency delivery of DSF was prepared.Next,copper-doped mesoporous silica nanoparticles（Cu-MSN）with different copper content was prepared,and the effects of copper content on drug loading are investigated.The results showed that the optimum drug loading conditions are 55℃,250 bar,and 6 h,and the drug loading of Cu-MSN is recorded up to 30.8%.In vitro and in vivo experiments showed that MSN/DSF and Cu MSN/DSF could effectively slow down the growth rate of tumor,prolong the survival cycle of mice,and Cu-MSN/DSF has the best antitumor effect.Together,these results have suggested that the fabrication of DSF loaded Cu-MSN prepared by SSI approach efficiently promoted the antitumor effect and may have a significant potential in tumor treatment.Finally,according to the interactions between ultra-small copper sulfide nanodots（CuS NDs）and metal-binding drug,CuS NDs and diethyldithiocarbamate（DDTC,metabolite of DSF）are used to prepare a novel multifunctional nanoplatform,DDTC loaded CuS NDs（CuS-DDTC NDs）,for the synergistic effect of photothermal and copper ion synergistic chemotherapy guided by multimodal imaging on tumor site.The results showed that the drug loading of DDTC can be adjusted by controlling the mass ratio of CuS NDS and DDTC.Considering the safety of normal cells,the CuS-DDTC NDS prepared at the mass ratio of 100:1 is used in the further experiments.The results showed that the addition of DDTC had no significant effect on the photothermal and photodynamic properties of CuS NDs.Combined with the results of photoacoustic imaging and distribution in vivo,12 h after intravenous injection,the biodistribution of CuS DDTC NDS in the tumor site is 3.0%.At the same time,CuS-DDTC NDS are rapidly excreted from the body.After 48 h of intravenous injection,the excretion amount in feces and urine is close to 37.2 and 2.8%,respectively.Both in vitro and in vivo experiments showed the good synergistic therapeutic effect via combining photothermal therapy and ion enhanced chemotherapy.Under the laser irradiation,CuS-DDTC NDS could effectively ablate cells and inhibit the tumor recurrence,suggesting the CuS-DDTC NDs is promising for applications towards cancer ablation.In conclusion,we have successfully prepared sub-micronized DSF and CuET particles,Cu-MSN/DSF sustained-release drug delivery system,and metabolizable CuS-DDTC NDs to improve the antitumor effect of DSF and provide a variety of promising strategies for the future development of DSF drug delivery system for cancer treatment. |
