PEO hot melt extrudates for controlled drug delivery: Importance of the type of drug and loading

A variety of poly(ethylene oxide) (PEO)-based matrix tablets loaded with theophylline, ibuprofen or metoprolol tartrate was prepared via hot melt extrusion. The initial drug loading varied from 10 to 60%, the PEO polymer molecular weight 300 7000 kDa. extrudates were characterized before and after exposure phosphate buffer pH 7.4 at 37 °C using optical scanning electron microscopy, X-ray diffraction analysis release measurements. In case tartrate, resulting rates monotonically increased increasing loading, irrespective grade. This can be attributed an “increased porosity effect” upon leaching, in less hindrance for subsequent release. However, theophylline ibuprofen, also “limited solubility effects” played a role even dominant kDa PEO-based extrudates: Upon water penetration into system, not all dissolved. Dissolved non-dissolved co-existed. Importantly, only dissolved is available diffusion. Thus, content did increase concentration gradients (and absolute absence effects), but 100% reference values. Interestingly, extrudates, dominated drugs, relative always loading. At 1000 kDa, released rate decreased depending type drug.