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

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Fur<strong>the</strong>rmore, HME h<strong>as</strong> successfully been employed <strong>as</strong> a robust <strong>technique</strong> to <strong>for</strong>msolid dispersions <strong>of</strong> APIs into polymer matrices via intermolecular interactions. The existence<strong>of</strong> amorphous APIs in <strong>the</strong> polymer matrices h<strong>as</strong> been confirmed by <strong>the</strong>rmal analysis.Molecular modelling w<strong>as</strong> used to predict/<strong>as</strong>sess <strong>the</strong> possible presence and strength <strong>of</strong>intermolecular interactions between drug and polymer molecules. The <strong>for</strong>egoing w<strong>as</strong>confirmed by FT-IR and NMR studies. XPS analysis w<strong>as</strong> used to confirm <strong>the</strong> mechanism <strong>of</strong><strong>the</strong> interaction via H-bonding between <strong>the</strong> carboxyl group <strong>of</strong> <strong>the</strong> anionic methacrylateco-polymer and <strong>the</strong> amide group <strong>of</strong> <strong>the</strong> active substances and estimate <strong>the</strong> bond strengthsinvolved. The <strong>for</strong>egoing studies confirmed that <strong>the</strong> stronger <strong>the</strong> interaction betweenoppositely charged drug and <strong>the</strong> polymer, <strong>the</strong> better <strong>the</strong> t<strong>as</strong>te m<strong>as</strong>king in extruded soliddispersions.The rele<strong>as</strong>e patterns <strong>of</strong> HCS from tablets processed by HME were governed by <strong>the</strong><strong>the</strong>rmal characteristics <strong>of</strong> <strong>the</strong> polymer used <strong>as</strong> a carrier during <strong>the</strong> <strong>extrusion</strong> process and <strong>the</strong>enteric coatings <strong>of</strong> <strong>the</strong> polymer, respectively. The tablets were designed to rele<strong>as</strong>e HCS in apattern that imitates <strong>the</strong> cortisol level in healthy individuals. Fur<strong>the</strong>rmore, a full comparativeanalysis <strong>of</strong> <strong>the</strong> mechanism <strong>of</strong> drug rele<strong>as</strong>e confirmed <strong>the</strong> rele<strong>as</strong>e <strong>of</strong> HCS in extruded tabletsaccording to a first order kinetic model.9.2 Future workThe scope <strong>of</strong> <strong>the</strong> HME technology h<strong>as</strong> already broadened to include a range <strong>of</strong> polymersand APIs that can be processed through <strong>the</strong> application <strong>of</strong> supercritical fluids and pl<strong>as</strong>ticizer<strong>as</strong>sisted HME.Future work using HME could include <strong>the</strong> following. <strong>Development</strong>, optimization and characterization <strong>of</strong> various orallydispersible/bioadhesive film <strong>for</strong>mulations. Hot-<strong>melt</strong> extruded films would be able todeliver high amounts <strong>of</strong> t<strong>as</strong>te m<strong>as</strong>ked drugs and, <strong>the</strong>re<strong>for</strong>e, would incre<strong>as</strong>e patientcompliance. Formulation <strong>of</strong> various APIs with lipids <strong>for</strong> sustained rele<strong>as</strong>e <strong>of</strong> drugs, using HMEalso need to be explored in order to facilitate cold <strong>extrusion</strong> <strong>for</strong> heat sensitive APIs. The growing market in medical devices, including incorporating drugs such <strong>as</strong>biodegradable stents and drug-loaded ca<strong>the</strong>ters will undoubtedly require HMEmanufacturing processes. These are required to be commercialised and may lead tonew are<strong>as</strong> <strong>of</strong> inter-discipinary research in <strong>the</strong> are<strong>as</strong> <strong>of</strong> pharmaceutics, medical devicesand biotechnology.171 | P a g e

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