International Institute for the Science of Sintering
Abstract
Formulation of solid dispersions is one of the most feasible strategies for overcoming the poor
drugs’ solubility – one of the major issues affecting drug bioavailability and therapeutic outcomes.
Since traditional methods used for preparation of solid dispersions often require usage of organic
solvents, it is of great importance to seek for more environment-friendly methods. It has been
demonstrated that supercritical (sc) CO2 may be effectively utilized for dispersion of drugs into the
suitable carrier (polymer), thus obtaining solid dispersions with the improved drug dissolution rate.
The aim of the presented study was to investigate the potential of scCO2 for preparation of poorly
soluble antihypertensive drugs (carvedilol and valsartan) solid dispersions in the conventional
pharmaceutical polymers (polyvinilypyrolidone-PVP and hypromellose-HPMC). Prepared solid
dispersions were characterized by scanning electron microscopy, differential scanning calorimetry
and Fourier-transform infrared spectroscopy; their porosity and density were determined and drug
dissolution rate was assessed and compared to the results obtained from solid dispersions prepared
by the traditional solvent casting method. Selected samples were tested for their tableting properties
as well. It has been demonstrated that scCO2 may be successfully applied for preparation of
carvedilol or valsartan solid dispersions with the improved drug dissolution rate. Further
characterization revealed the nature of interactions between the drugs and selected polymers. Due
to the low density (and high porosity), some of the prepared solid dispersions may be used for
further development of the floating dosage forms. It has also been demonstrated that some of the
prepared dispersions have excellent compressibility and compactibility, which is of great
importance for further development of solid dosage forms. The obtained results provide framework
for further development of environment-friendly methods in pharmaceutical development and
production