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A method was elaborated to prepare flame retarded self-reinforced polypropylene composites by injection moulding. The effect of intumescent flame retardant (FR) loading was comprehensively investigated on the morphology, flammability, and mechanical properties of the self-reinforced polypropylene composites and compared with non-reinforced counterparts of identical additive contents. Homogeneous distribution of both the reinforcing polypropylene fibres and the FR additive was achieved endowing significantly improved strength and stiffness accompanied with increased fire resistance. At 10% FR content, 37% reduction of peak of heat release rate, UL94 V-2 rating, and LOI of 24.5 vol% were achieved without compromising the improved mechanical performance of the injection moulded self-reinforced composites, ie, a 4-fold increase of tensile strength and a 7-fold increase of tensile modulus were reached compared with the non-reinforced counterpart. At higher loading (15% FR), the FR properties improved further (LOI of 29.5 vol% was reached); however, due to the abrasive effect of the FR particles in the matrix, the structure of the reinforcing fibres tends to get damaged during the thermo-mechanical processing, and thus their reinforcing efficacy deteriorated. It is demonstrated that the combination of polymer fibre reinforcement with other fillers (such as FRs) is advantageous and feasible even by injection moulding, but the balance between the individual attributed properties needs to be found. [ABSTRACT FROM AUTHOR]

Immediate-release solid dispersions of a slowly dissolving active pharmaceutical ingredient, spironolactone, were prepared by supercritical-CO2-assisted melt extrusion (a solvent-free and continuous manufacturing technology) using Eudragit E as matrix. Through optimizing process parameters (i.e. temperature, melt throughput, pressure and CO2 flow), stable foams with high porosity, homogeneous structure and thin (even submicronic) walls could be prepared, as revealed by scanning electron microscopy. The samples were found to be rigid enough to mill, enabling further processing, as is necessary to formulate tablets. The influence of extrusion temperature and melt throughput on residual drug crystallinity was measured using non-invasive confocal Raman mapping coupled with chemometric analysis, while the influence on the degree of drug degradation was determined using high performance liquid chromatography. The plasticizing effect of supercritical CO2 was shown to reasonably improve the purity of the prepared solid dispersions by enabling high-yield production at lower temperature ranges. At the same time, shorter residence time and lower temperature slightly increased residual drug crystallinity. The obtained foamy structures ensured immediate drug dissolution in an acidic medium. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Dispersing at the molecular level a drug in a polymer matrix is a major challenge to be addressed by the pharmaceutical industry to enhance its bioavailability or to control its release. Melt extrusion and supercritical CO2-aided melt extrusion of solid pharmaceutical formulations were performed to enhance the dissolution rate of carvedilol, taken as a model of poorly soluble drug. The presence of the drug improved the processability of the polyacrylate matrix (Eudragit E) through its plasticizing effect. The supercritical method was found gentle compared with melt extrusion owing to the shorter residence time and lower processing temperature and melt viscosity. No traces of decomposition of the drug could be detected after the supercritical extrusion process based on capillary electrophoresis results. This extrusion process resulted in effective homogenization of the components and amorphization of the drug according to Raman mapping, Fourier transform infrared spectrometry, X-ray diffraction, and polarized light microscopy. The kinetics of dissolution can be dramatically improved. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]