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

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Fdid ,Vi F2pip , p( Ehi/ ViVi )i = structural groups within <strong>the</strong> molecule = <strong>the</strong> total solubility parameter.F di = molar attraction constant due to molar dispersion <strong>for</strong>cesF 2 pi = molar attraction constant due to molar polarization <strong>for</strong>cesE hi = hydrogen bonding energy.Vi = group contribution to molar volumeThe average molecular weight w<strong>as</strong> used to determine <strong>the</strong> solubility parameter <strong>of</strong> differentpolymeric excipients while <strong>the</strong> Bagley advanced solubility parameter equation and diagrams [24]were used to investigate <strong>the</strong> effect <strong>of</strong> hydrogen bonding compared to <strong>the</strong> combined solubilityparameters (dispersion <strong>for</strong>ces and polarization <strong>for</strong>ces).2.3 Preparation <strong>of</strong> <strong>for</strong>mulation blendsThe dry drug/polymer powders (100 g) were blended thoroughly in a Turbula TF2 mixer(B<strong>as</strong>el, Switzerland) <strong>for</strong> 10 min. As shown in Table 2.1, <strong>the</strong> drug content <strong>for</strong> <strong>the</strong> binary blendsvaried from 20 – 40%. For <strong>the</strong> FMT/VA64, FMT/S630 and INM/S630 <strong>the</strong> drug content did notexceed 20% due to <strong>the</strong> difficulty with extruding <strong>the</strong> powdered <strong>for</strong>mulations.Table 2.1: Drug/polymer percentages <strong>of</strong> <strong>the</strong> HME processed <strong>for</strong>mulations.Drug Polymer Drug(%, w/w)Polymer(%, w/w)FMT SOL 20 80FMT SOL 40 60FMT VA64 20 80FMT S630 20 80Drug Polymer Drug Polymer21 | P a g e

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