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

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Fig. 2.5e: DSC <strong>the</strong>rmograms <strong>of</strong> FMT and SOL (physical mixtures and extrudates).3.5 In vitro dissolution studiesThe dissolution pr<strong>of</strong>iles <strong>of</strong> INM and FMT from SOL, VA64 and S630 extruded (EXT)granules are shown in Fig. 2.6a- b. The dissolution rates <strong>of</strong> pure APIs were also investigated tosignify <strong>the</strong> incre<strong>as</strong>e <strong>of</strong> <strong>the</strong> dissolution rates <strong>of</strong> <strong>the</strong> extruded <strong>for</strong>mulations.Due to its low water solubility, <strong>the</strong> bulk INM powder showed very slow dissolution ratesup to 5% within five hours. In contr<strong>as</strong>t, <strong>the</strong> dissolution pr<strong>of</strong>iles <strong>of</strong> INM extruded <strong>for</strong>mulationsexhibited enhanced dissolution rates compared to <strong>the</strong> bulk INM powder <strong>as</strong> shown in Fig 2.6a.The extrudates <strong>of</strong> SOL, VA64 and S630 polymers at 20% INM loadings exhibited incre<strong>as</strong>eddissolution rates with 30 – 40% rele<strong>as</strong>ed in 120 min and 55 – 70% in 300 min. SOL showedslightly incre<strong>as</strong>ed rele<strong>as</strong>ed rates compared to VA64 and S630 without significant differences <strong>as</strong>shown by a Kruskal – Wallis nonparametric test (p>0.05) (GraphPad, InStat, S<strong>of</strong>tware, US).Interestingly, <strong>the</strong> INM loading level w<strong>as</strong> shown to have an effect on <strong>the</strong> dissolution rates. Thedrug dissolution rate at high drug loadings tended to incre<strong>as</strong>e with an incre<strong>as</strong>e in <strong>the</strong> INM level.This phenomenon w<strong>as</strong> attributed to <strong>the</strong> pl<strong>as</strong>ticization effect <strong>of</strong> INM on VA64. There<strong>for</strong>e, at 40%INM loading <strong>the</strong> drug rele<strong>as</strong>e rate <strong>of</strong> INM/SOL and INM/VA64 granules w<strong>as</strong> 55–65% in 120min and 75–80% in 300 min.35 | P a g e

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