PubMed · 13046655
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S GURIN. 1953-06-04. Lipogenesis.. https://doi.org/10.1056/nejm195306042482302
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The effect of incorporating caffeine and paracetamol on the structure and behaviour of Gelucire 50/13 has been studied with a view to establishing whether the choice of drug influences the solid structure and release mechanism. Dispersions containing up to 30% w/w drug were prepared and studied using differential scanning calorimetry (DSC), hot stage differential interference contrast microscopy (HSM), dissolution studies and erosion, water uptake (WU) and diameter change measurements. Gelucire 50/13 alone showed a broad melting endotherm using DSC, with two dominant peaks at 36 and 44 degrees C. While incorporation of caffeine did not result in marked changes to the profile, the presence of paracetamol increased the proportion of material in the lower melting peak. HSM studies indicated that the Gelucire crystallised into two main spherulitic conformations; paracetamol appeared to act as a nucleation site for the lower melting fractions while caffeine particles changed into a needle-shaped morphology on cooling the system from the liquid state. Dissolution studies at 37 degrees C showed the caffeine to be released at a relatively faster rate than the paracetamol. Kinetic modeling and direct measurement of the erosion profile indicated that the caffeine systems showed a greater preponderance for erosion than did the corresponding paracetamol systems. It is suggested that the paracetamol promotes the generation of the lower melting form of Gelucire 50/13 which in turn influences the release rate and mechanism. The study therefore indicates that the influence of the drug should be carefully considered when studying Gelucire matrix systems.
This study was performed in order to evaluate the effects of binder droplet size and type of binder on the agglomerate growth mechanisms by melt agglomeration in a fluidised bed granulator. Lactose monohydrate was agglomerated with melted polyethylene glycol (PEG) 3000 or Gelucire 50/13 (esters of polyethylene glycol and glycerol), which was atomised at different nozzle air flow rates giving rise to median droplet sizes of 40, 60, and 80 microm. Different product temperatures were investigated, below the melting range, in the middle of the melting range, and above the melting range for each binder. The agglomerates were found to be formed by initial nucleation of lactose particles immersed in the melted binder droplets. Agglomerate growth occurred by coalescence between nuclei followed by coalescence between agglomerates. Complex effects of binder droplet size and type of binder were seen at low product temperatures. Low product temperatures resulted in smaller agglomerate sizes, because the agglomerate growth was counteracted by very high binder viscosity or solidification of the binder. At higher product temperatures, neither the binder droplet size nor the type of binder had a clear effect on the final agglomerate size.
Rich diet and lack of exercise are causing a surge in the prevalence of obesity and hepatic steatosis, which causes "primary" steatohepatitis in some patients. Ultrastructural mitochondrial lesions, decreased activity of respiratory chain complexes, and impaired ability to synthesize ATP are observed in these patients. Reactive oxygen species (ROS) may increase tumor necrosis factor-alpha (TNF-alpha) production and also oxidize fat deposits. TNF-alpha and lipid peroxidation products impair the flow of electrons along the respiratory chain, causing overreduction of respiratory chain components and enhanced mitochondrial ROS formation. Steatohepatitis can also be due to alcohol, drugs, or other causes that either directly increase ROS formation or first impair respiration, which secondarily increases ROS formation. Higher ROS formation in secondary steatohepatitis could cause more lipid peroxidation, cytokine induction, and fibrogenesis than in primary steatohepatitis.