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Development of hot-melt extrusion as a novel technique for the ...

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immiscibility <strong>of</strong> <strong>the</strong> two components. However, <strong>the</strong> difference from <strong>the</strong> value given by Albers(2008) is marginal and <strong>the</strong> components were considered miscible.Table 2.2: Calculated solubility parameters <strong>of</strong> drug/polymers and compound distances in Bagleydiagram.Sampled(MPa 0.5 )p(MPa 0.5 )v(MPa 0.5 )h(MPa 0.5 ) average(MPa 0.5 )∆ (INM)(MPa 0.5 )∆ (FMT)(MPa 0.5 )Ra(v)INM(MPa 0.5 )Ra(v)FMT(MPa 0.5 )INM 18.99 7.37 20.34 10.34 22.84 - - - -FMT 11.93 15.00 19.17 13.49 23.44 - - - -VA64 18.0 0.64 18.01 7.73 19.60 3.24 3.84 3.49 5.87SOL 15.14 0.45 15.15 12.18 19.43 3.41 3.99 5.54 4.23S630 13.0 8.80 15.70 9.17 18.18 4.66 5.26 4.79 5.54Never<strong>the</strong>less, both approaches confirmed <strong>the</strong> miscibility <strong>of</strong> <strong>the</strong> binary mixtures <strong>for</strong> all<strong>for</strong>mulations. It is worth mentioning that <strong>the</strong> manufacturing <strong>of</strong> solid dispersions via HMEdepends also on <strong>the</strong> processing parameters such <strong>as</strong> temperature pr<strong>of</strong>ile and screw rotation speedwhich are not taken into account in <strong>the</strong> estimated solubility parameters by Van Kreveln/H<strong>of</strong>tyzeror Bagley. Thus, fur<strong>the</strong>r process optimization is required <strong>for</strong> <strong>the</strong> manufacturing <strong>of</strong> soliddispersions in order to incre<strong>as</strong>e drug solubility.As can be seen in Table 1, no pl<strong>as</strong>ticizer w<strong>as</strong> incorporated in <strong>the</strong> binary mixtures due tolow gl<strong>as</strong>s transition temperatures <strong>of</strong> <strong>the</strong> selected polymers. All <strong>for</strong>mulations were e<strong>as</strong>ily extrudedat temperatures around 120 o C even at high drug loadings.[Ple<strong>as</strong>e see supplementary chapter 10, section 10.2 <strong>for</strong> examples <strong>of</strong> <strong>the</strong> calculation <strong>of</strong>solubility parameters <strong>of</strong> different drug and polymers by using Van Krevelen/ H<strong>of</strong>tyzer equation]26 | P a g e

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