The objective of this study was to elucidate the feasibility to improve the solubility and bioavailability of poorly water-soluble itraconazole via solid dispersions by using supercritical fluid (SCF). Solid dispersions of itraconazole with hydrophilic polymer, HPMC 2910, were prepared by the aerosol solvent extraction system (ASES) under different process conditions of temperature/pressure. The particle size of solid dispersions ranged from 100 to 500 nm. The equilibrium solubility increased with decrease (15 to 10 MPa) in pressure and increase (40 to 60 degrees C) in temperature. The solid dispersions prepared at 45 degrees C/15 MPa showed a slight increase in equilibrium solubility (approximately 27-fold increase) when compared to pure itraconazole, while those prepared at 60 degrees C/10 MPa showed approximately 610-fold increase and no endothermic peaks corresponding to pure itraconazole were observed, indicating that itraconazole might be molecularly dispersed in HPMC 2910 in the amorphous form. The amorphous state of itraconazole was confirmed by DSC/XRD data. The pharmacokinetic parameters of the ASES-processed solid dispersions, such as Tmax, Cmax, and AUC(o-24 h) were almost similar to Sporanox capsule which shows high bioavailability. Hence, it was concluded that the ASES process could be a promising technique to reduce particle size and/or prepare amorphous solid dispersion of drugs in order to improve the solubility and bioavailability of poorly water-soluble drugs.
Cefuroxime axetil (CA) solid dispersions with HPMC 2910/PVP K-30 were prepared using solution enhanced dispersion by supercritical fluids (SEDS) in an effort to increase the dissolution rate of poorly water-soluble drugs. Their physicochemical properties in solid state were characterized by differential scanning calorimeter (DSC), powder X-ray diffraction (PXRD), Fourier transform infrared spectrometry (FT-IR) and scanning electron microscopy. No endothermic and characteristic diffraction peaks corresponding to CA were observed for the solid dispersions in DSC and PXRD. FTIR analysis demonstrated the presence of intermolecular hydrogen bonds between CA and HPMC 2910/PVP K-30 in solid dispersions, resulting in the formation of amorphous or non-crystalline CA. Dissolution studies indicated that the dissolution rates were remarkably increased in solid dispersions compared with those in the physical mixture and drug alone. In conclusion, an amorphous or non-crystalline CA solid dispersion prepared using SEDS could be very useful for the formulation of solid dosage forms.
The objective of this study was to develop oral controlled release delivery systems for tamsulosin hydrochloride (TSH) using alginate beads with various waxy materials, such as Compritol 888 ATO, Precirol ATO 5 and Gelucires. The beads were prepared from sodium alginate-waxy material-TSH slurry dropped onto calcium chloride to form spherical beads. The effects of the addition of various waxy materials to alginate beads on the drug encapsulation efficiency, bead size and morphology were investigated. The drug encapsulation efficiency significantly increased with the addition of waxy materials. The TSH-loaded alginate beads with and without waxy materials were almost spherical particles with an average diameter of 1.44 and 1.22 mm, respectively. In dissolution study, the TSH-loaded alginate beads with waxy materials exhibited controlled release behaviour over a 6-h period, while beads without waxy materials showed release of 100% TSH within 2 h. These results may be attributed to the formation of a more rigid alginate matrix structure due to incorporated waxy materials. From the Dunnett's t-test and the f2 factor, the release of TSH from alginate beads, a similar dissolution pattern to that of the marketed product (Harunal capsules) could be achieved by adding Gelucire 50/13 into TSH-loaded alginate beads. From these results, oral controlled release of TSH could be achieved with loading in alginate beads with waxy materials, such as Compritol 888 ATO, Precirol ATO 5 and Gelucires.
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