1,721,073 research outputs found
Rapidly dissolving extrudates prepared by a warm extrusion process
No full textIn this study, the suitability as rapid release dosage forms for ibuprofen of cylindrically shaped extrudates based on Gelucire 50/13 and Polyethylene glycol 4000 was investigated. Several drug to carrier weight ratios were processed in a small-scale ram extruder at a temperature much lower than the melting point of the binders. Cylindrical extrudates, regular in shape and with a smooth surface were obtained. In the Gelucire 50/13/ibuprofen extrudates, only a slight reduction of drug crystallinity compared to the relative physical blends was found, which in any case, did not affect the stability of the systems. While in the Gelucire case the ibuprofen dissolution was improved even by a little percentage of carrier in the formulation, with Polyethylene glycol 4000 the introduction of additional hydrophilic excipients was found to be necessary to achieve a dissolution rate and extent of dissolution of the drug comparable to those of Gelucire/ibuprofen systems
An investigation into the release behavior of solid lipid microparticles in different simulated gastrointestinal fluids
No full textIn recent years there has been a growing interest in solid lipid-based systems, particularly in solid lipid microparticles
(SLMs); however, only very few studies deeply investigated the dissolution behaviour of orally
delivered-SLMs. The present study provides new insights about the release performance in different gastrointestinal
fluids of SLMs containing a freely water soluble drug (caffeine, as BCS class I drug). Three different
formulations of SLMs were prepared by spray congealing using lipid excipients belonging to three chemical
classes: fatty acids, triglycerides and waxes. The dissolution profiles of caffeine were investigated using various
updated biorelevant dissolution media simulating the conditions of the gastrointestinal tract (gastric tract and
proximal human intestine). The profiles were statistically compared and the morphological changes of the
particles after dissolution were assessed by SEM analysis. The influence of the SLMs composition resulted to be
crucial on the dissolution behavior in the case of bigger particles (> 250 μm), while smaller SLMs (100-250 μm)
were mainly affected by the fluid composition. Moreover, regardless of the particle size, greater differences in
drug release profiles were noted by using different intestinal media compared to those obtained in gastric media.
In particular, the drug release from fatty acid and triglyceride-based SLMs was more controlled in the phosphate
buffer than in the intestinal biorelevant media; while the opposite behavior was noticed for waxy-bases SLMs.
Overall, the present study provides interesting insights which can be useful for the design of a multiparticulated
solid lipid formulation
Theretical and experimental characterisation of stearic acid based sustained release devices obtained by hot melt co-extrusion
No full textThis study was conducted to develop and characterize a hot melt co-extruded cylindrical system for controlled drug delivery. Different lengths
and configurations (homogeneous, hollow and heterogeneous) co-extrudates were considered. Stearic acid and polyethylene glycol were used as
hydrophobic and hydrophilic components, respectively. Acetaminophen and theophylline were used as model drug. Release kinetics were studied
on the basis of in vitro tests and experimental data were analyzed by a new mathematical model accounting for drug dissolution and diffusion
inside the cylindrical matrix. Surface tension measurements were carried on the two model drugs and the hydrophobic matrix. Experimental results
showed that co-extruded length and configuration sensibly affect release kinetics of both drugs. Additionally, the proposed mathematical model
proved to be reliable and yielded an explanation for the lower acetaminophen release rate with respect to that of theophylline. This behavior could
be explained by the formation of a low permeable layer surrounding the acetaminophen-loaded systems. In addition, surface property analysis
evidenced the higher hydrophobic nature of acetaminophen-loaded systems with respect to theophylline systems
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