Preparation,Characterization And The In Vivo Bioavailability Of Amorphous Amphotericin B Nanoparticles For Oral Administration Through Liquid Antisolvent Precipitation

Amphotericin B(AmB)is a polyene macrolide antibiotic,which was isolated from Streptomyces nodosus in 1955.AmB is the classic broad-spectrum agent for systemic fungal infections and it remains the gold standard therapy for fungal infections.The mechanism of action of this highly effective antifungal is binding to the ergosterol in the cell membrane of fungi and some protozoan parasites,which disrupts cell membrane integrity.Membrane pore formation damages membrane permeability,which causes the leakage of important materials,leading to fungal cell death.However,the poor water solubility of AmB limits its application.Therefore,the key issues need to be resolved in AmB applications are to improve its water solubility,increase its oral absorption,and enhance its vivo bioavailability.In recent years,nanotechnology is a new formulation technology and the commanding point in the 21st century.It is not only to increase the solubility of poorly soluble drugs,to improve the bioavailability of drugs in the body,but also has targeted,sustained-release characteristic to enhance the drug efficacy and reduce side effects,etc.This project tried to improve the water solubility of AmB using nanotechnology,improve drug bioavailability and enhance the oral absorption,making AmB a more effective antifungal oral drug.This project focused on the solubility of AmB for oral administration and prepared AmB nanoparticles through liquid antisolvent precipitation and by freeze-drying.The liquid antisolvent precipitation was optimized trough a single-factor experiment.We determined the effects of surfactants and their concentration,the stirring time,the precipitation temperature,the stirring intensity,the drug concentration and the volume ratio of antisolvent to solvent on the mean particle size(MPS)of the AmB nanoparticles.For the obtained optimal AmB nanoparticles through single-factor experiment conduct physicochemical property testing and other test,including scanning electron microscopy(SEM),mass spectrometry(MS),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),differential scanning calorimetry(DSC),thermal gravimetric analysis(TG),solvent residue,drug purity test,dissolution test and bioavailability.1.The liquid antisolvent precipitation was optimized through a single-factor experiment.the optimal conditions for AmB nanoparticles preparation are as follows:0.15%Tween-80,stirring time of 30 min,precipitation temperature of 12?,stirring intensity of 2000 r/min,drug concentration of 20mg/mL,and antisolvent to solvent volume ratio of 13/1.The experimental results show that increased stirring intensity and precipitation time favored AmB nanoparticles with smaller MPS,but precipitation times exceeding 30 min did not further reduce the MPS and almost remain unchanged.Increased Tween-80 concentration and the drug concentration increased the MPS of the AmB nanoparticles.Increased precipitation temperature and antisolvent to solvent volume ratio initially decreased the MPS of the AmB nanoparticles,which increased thereafter.Optimum conditions produced AmB nanoparticles with an MPS of 135.1 nm.2.Physicochemical property testing and other test:The SEM demonstrated that AmB nanoparticles produced through were almost spherical.It were significantly smaller and more uniform than the raw AmB,which indicates better solubility.The FTIR and MS analyses demonstrated that the molecular structure of the AmB nanoparticles was unchanged after liquid antisolvent precipitation.The XRD and DSC analyses indicated that the prepared AmB nanoparticles were changed from crystalline to amorphous.The solvent residue result demonstrated that the residual DMSO in the AmB nanoparticles was 0.24%lower than the the International Conference on Harmonization(ICH)limit for class ? solvents.The AmB nanoparticles exhibited 2.1 times faster dissolution rate and 13 times equilibrium solubility compared with the raw drug.These detection results indicate that the AmB nanoparticles potentially improved the oral absorption of AmB.3.In the bioavailability studies of rats,the AmB content in rat plasma was detected by high performance liquid chromatography(HPLC).The results show that the raw AmB almost without being absorbed in animals.However,AmB nanoparticles have an abvious increase.The relative bioavailability was 4.95 times more than the raw AmB.Through the above experimental results,the prepared AmB nanoparticles had uniform particle size distribution,shapeed rules spherical.And the physical and chemical properties of AmB nanoparticles were stability.The water-soluble of AmB get abvously improved,and the bioavailability of AmB has an abvious increase.