Paclitaxel(PTX) is an effective anticancer drug with poor solubility in water.Recently

much effort has been devoted into alternative formulations of PTX for improving its aqueous solubility.In this study

PTX and poly(L-lactic acid)(PLLA) were co-precipitated by a supercritical antisolvent(SAS) process using dichloromethane(DCM) and the mixtures of DCM/ethanol(EtOH) or DCM/dimethyl sulfoxide(DMSO) as the solvent

with super-critical carbon dioxide as the antisolvent.The effects of solvent

solvent ratio

temperature

pressure

polymer concentration and solution flow rate on particle morphology

mass median diameter(

D

p

50

) and PTX loading were investigated using single-factor method.The particle samples were characterized using X-ray diffraction(XRD)

scanning electron microscopy(SEM)

laser diffraction particle size analyzer and high pressure liquid chromatography(HPLC).XRD results indicate that the micronized PTX is dispersed into the PLLA matrix in an amorphous form.SEM indicates that the solvent and the solvent ratio have great effect on the particle morphologies

and particle morphology is good at the volume ratio of DCM/EtOH of 50/50.For the mixed DCM/EtOH solvent

D

p

50

increases with the increase of the temperature

pressure

PLLA concentration and solution flow rate

and PTX loading increases with pressure.Suitable operating conditions for the experimental system are as follows:DCM/EtOH 50/50(by volume)

35℃

10-12 MPa

PLLA concentrat

ion of 5 g·L

-1

and solution flow rate of 0.5 ml·min

-1

.