Mesoporous tablet-shaped potato starch aerogels for loading and release of the poorly water-soluble drug celecoxib

In this study,after determination of the optimal values of the effective parameters in the synthesis using experimental design software,tablet-shaped potato starch aerogels were synthesized at the optimal condition in order to be used as a drug carrier.The celecoxib,as the model drug,was loaded into the aerogel matrix during the solvent exchange step.FTIR(Fourier Transform Infrared Spectroscopy),FESEM and HRTEM(Transmission Electron Microscopy)analyses showed that celecoxib has been successfully loaded into aerogel matrix.Also,XRD analysis showed that most of the celecoxib has been loaded in amorphous form.In vitro studies were performed in both simulated gastric and intestinal fluids.The release kinetics showed that the loaded celecoxib dissolved faster than crystalline celecoxib.At rotational speed of 100 r·min^-1,about 26%and 50%and at rotational speed of 50 r·min^-1,about 20%and 42%drug was released during the first 30 min of soaking in the simulated gastric fluid and simulated intestinal fluid,respectively.The release of the mentioned drug was increased up to 60%and 98%at a rotational speed of 100 r·min^-1 and up to 46%and 93%at a rotational speed of 50 r·min^-1 at the end of 5 h in the simulated gastric fluid and simulated intestinal fluid,respectively.It could be concluded that potato starch aerogels can be very useful in many drug delivery applications along with conventional micronization techniques.Modeling of release data showed that the release kinetics follows the Korsmeyer Peppas model,which considers phenomena of matrix erosion and drug diffusion.

Reaction parameters influence on the catalytic performance of copper-silica aerogel in the methanol steam reforming

Steam reforming of methanol was carried out on the copper-silica aerogel catalyst.The effects of reaction temperature,feed rate,water to methanol molar ratio and carrier gas flowrate on the H_2 production rate and CO selectivity were investigated.M ethanol conversion was increased considerably in the range of about 240-300,after which it increased at a slightly lower rate.The used feed flowrate,steam to methanol molar ratio and carrier gas flowwere 1.2-9.0 m L/h,1.2-5.0 and 20-80 m L/min,respectively.Reducing the feed flowrate increased the H_2 production rate.It was found that an increase in the water to methanol ratio and decreasing the carrier gas flowrate slightly increases the H2production rate.Increasing the water to methanol ratio causes the lowest temperature in which CO formation was observed to rise,so that for the ratio of 5.0 no CO formation was detected in temperatures lower than 375℃.In all conditions,by approaching the complete conversion,increasing the main product concentration,increasing the temperature and contact time,and decreasing the steam to methanol ratio,the CO selectivity was increased.These results suggested that CO was formed as a secondary product through reverse water-gas shift reaction and did not participate in the methanol steam reforming reaction mechanism.