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

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Fig. 3.2: X-ray diffraction patterns <strong>of</strong> pure IBU, physical IBU/EPO mixture and extrudedIBU/EPO granules, respectively.When IBU w<strong>as</strong> processed at 40% loading, no significant peaks were apparent in <strong>the</strong>diffractogram indicating amorphous IBU even at high drug loadings. The diffractograms did notpresent any changes after one year storage and no IBU re–crystallization w<strong>as</strong> observed. DSCw<strong>as</strong> also used to study <strong>the</strong> IBU state within <strong>the</strong> EPO matrix. In Fig. 3.3 <strong>the</strong> IBU <strong>melt</strong>ing pointw<strong>as</strong> determined at 77.36 o C and at 76.69 o C <strong>for</strong> <strong>the</strong> physical mixture. The shift <strong>of</strong> <strong>the</strong> <strong>melt</strong>ingpoint is attributed to <strong>the</strong> IBU‘s pl<strong>as</strong>ticization effect. For <strong>the</strong> physical mixture <strong>the</strong> EPO gl<strong>as</strong>stransition temperature w<strong>as</strong> unchanged at 54.97 o C in comparison to <strong>the</strong> pure EPO (54.83 o C). The<strong>the</strong>rmogram <strong>of</strong> extruded IBU/EPO (40% loading) showed <strong>the</strong> absence <strong>of</strong> IBU <strong>melt</strong>ing and <strong>the</strong>existence <strong>of</strong> a single gl<strong>as</strong>s transition, T g . In fact, T g w<strong>as</strong> lowered at 29.49 o C clearly indicatingthat EPO h<strong>as</strong> been pl<strong>as</strong>ticized by <strong>the</strong> IBU. The presence <strong>of</strong> a single T g confirms <strong>the</strong> completemiscbility <strong>of</strong> IBU/EPO and <strong>the</strong> creation <strong>of</strong> a gl<strong>as</strong>sy solution where IBU is molecularly dispersedwithin EPO [27, 30] .48 | P a g e

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