Experimental Investigation On The Preparation Of Drug-loaded Porous Copolymer Mass Using Supercritical CO₂

To develop a kind of drug loaded copolymer material controlling drug release,reduce the side effects of drugs on human body and extend functionary time of the drug,supercritical CO₂ was used as nonsolvent to fabricate drug loaded copolymer masses.Supercritical CO₂ has unique advantages:easy to recycle,less toxic and environmentally friendly,hard to burn, safe to operate.Because of these advantages,supercritical CO₂ shows a good application prospects.Detailed experimental study of the preparation of drug loaded copolymer mass using supercritical CO₂ can lay some foundation for the theoretical research in the future.In this paper,no drug-loaded and drug-loaded cellulose acetate(CA) masses were prepared using supercritical CO₂.The structure of the masses was observed by scanning electron microscopy(SEM)and the state of the drug dispersed in the polymer was measured by Fouvier Transform Infrared Spectroscopy(FTIR).The drug loading content and release profiles were determined by UV spectrophotometer.The influence of pressurization rate, pressure fluctuation and depressurization rate was discussed.And a detailed study of the effect of temperature,pressure and concentration on the porosity and pore sizes was carried out.The results showed that the porosity increased with the increase of temperature,and decreased with the increase of polymer concentration,but increased to a peak and then decreased with the increase of pressure,the size of the pores increased with the increase of temperature,and decreased with the increase of pressure.In addition,amoxicillin was preliminarily loaded onto CA mass and the drug release profiles were investigated.The result indicated that drug loaded CA mass could control the drug release.Furthermore,no drug-loaded and drug-loaded polycaprolactone(PCL) and polylactide (PLA) masses were fabricated with this method.SEM,FTIR and UV spectrophotometer were used to analyze the microstructure of masses,state of the drug dispersed in the polymer and release profiles of the drug.How the sizes of pores changed with the change of pressure, temperature and concentration was investigated.Moreover,the effect of polymer ratio, thickness of the masses and drug loading on the release rate of drug was analyzed.The result indicated that the pores of PCL mass decreased with the increase of polymer concentration, increased with the increase of temperature and had little relationship with pressure,the pores of PLA mass increased with the increase of temperature,decreased with the increase of pressure and decreased with the increase of concentration,both of the drug release rate from drug-loaded PCL and PLA masses increased with the increase of PEG content,decreased with the increase of mass thickness and drug loading.Through experimental study,the preparation of copolymer mass using supercritical CO₂ is understood more deeply.So does the effects of every operation parameter on the pores and the release profiles of the drug.That provides an essential basis for the theoretical research of this process.