Preparation And Characterization Of Betulin Nanoparticles For Oral Hypoglycemic Drug By Antisolvent Precipitation

Betulin is a kind of pentacyclic triterpenoid which extracted from the bark of platyphylla.Betulin is known to exhibit a wide range of biological activities.Pharmacological tests show that betulin have antineoplastic activity,anti-inflammation and antianaphylaxis.The recent research shows that betulin also has hypoglycemic activity.However,Due to its low aqueous solubility and high permeability,betulin has low and variableoral bioavailability.Betulin is a kind of small molecule compound compared with insulin,it can not be break down protein by pepsin after oral administration.Betulin is a potential hypoglycemic drug.Hence,it's significative to enhance the bioavailability by improving the dissolution of betulin.The logP of betulin is tested to be 2.28 in our previous work.The result demonstrates that betulin belongs to the compound characterized with low solubility and high permeability.Studies show that it is possible to increase the bioavailability of this kind of compound by preparing nanocrystals that can improve dissolution rate.Top-down methods and down-top methods are two kinds of methods which are used generally to produce nanoparticles.Liquid antisolvent precipitation(LAS)is a kind of down-top methods which are commonly used to produce nanoparticles.LAS is reported as a simple and cost-effective approach with scale-up potential.LAS has been used toprecipitate nano-microparticles of various active pharmaceuticalingredients(APIs)by many researchers.In this work,to our knowledge,we prepared betulin nanoparticles suspension using antisolvent precipitation,which has not been reported in literature up to now.And the betulin nanoparticles powder obtained were characterized in vitro/in vivo,specific content as follows.1).The antisolvent precipitation process was optimized and the factors which influence the MPS of betulin nanoparticles suspension by single factor design were analyzed.And the betulin nanoparticles powder obtained were characterized using transmission electron microscope(TEM),Fourier-transform infrared(FT-IR)spectroscopy,Liquid chromatography coupled with tandem mass spectrometry(LC-MS/MS),X-ray diffraction(XRD),differential scanning calorimetry(DSC),thermogravimetric analysis(TGA),dissolution test and solvent residual.And the minimum MPS of betulin nanoparticles suspension was obtained when the concentration of betulin solution,the volume ratio of antisolvent to solvent,precipitation temperature,stirring intensity,precipitation time and the speed ratio solvent adding into antisolvent were 6.0 mg/mL,3.3,40?,1000 r/min,12 min and 5.5 min,respectively.Through a confirmatory test,betulin nanopartilces suspension with a MPS of about 110 nm was obtained.The TEM picture of betulin nanoparticles powder shows it has a nearly spherical shape.2).The residual ethanol in the betulin nanoparticles powder were analyzed using an Agilent 7890A gas chromatograph,The residual ethanol content in betulin nanoparticles is 2085 ppm Since the ICH limit for ethanol in class 3 solvents is 5000 ppm or 0.5%,the betulin nanoparticles powder met ICH requirements and is suitable for pharmaceutical use.3).Dissolution study of raw betulin and betulin nanoparticles powder was determined by HPLC.Artificial gastric juice was used as dissolvent in this part.The result demonstrates that the betulin nanoparticles powder showed a more rapid dissolution rates and higher solubility than the raw betulin.The maximum solubility(approximately 4.18 ?g/mL)was observed in betulin nanoparticles powder at 240 min.However,this of raw betulin was only 2.87 ?g/mL.4).Our work also compared the bioavailability of betulin nanoparticles to raw betulin.In this part,the concentration of the betulin in plasma of rat was detected by HPLC.And the results demonstrate that oral administration of betulin nanoparticules powder leads to 121%increase in bioavailability.5).In vivo evaluation on diabetic animals taking betulin nanoparticles powder were also performed.The pancreas of the rat which were used in this part were destroyed.The blood GLU concentration was measured using blood GLU assay kits.The result of in vivo evaluation on diabetic animals demonstrates that the betulin nanoparticles powder show an excellent hypoglycemic effect compared with raw betulin.In conclusion,the betulin nanoparticles obtained under the optimum condition have narrow size distribution.The solubility in water,bioavailability and Hypoglycemic effect of betulin nanoparticle powder are improved in compared with raw betulin..