Homogeneity of amorphous solid dispersions – an example with KinetiSol®

KinetiSol^® is a high-shear, fusion-based technology capable of producing stable amorphous solid dispersions (ASDs) without the assistance of solvent. KinetiSol^® has proven successful with multiple challenging BCS class II and IV drugs, where drug properties like thermal instability or lack of appreciable solubility in volatile solvents make hot melt extrusion or spray drying unfeasible. However, there is a necessity to characterize the ASDs like those made by the KinetiSol^® process, in order to better understand whether KinetiSol^® is capable of homogeneously dispersing drug throughout a carrier in a short (<40?s) processing time. Our study utilized the high melting point, BCS class II drug, meloxicam, in order to evaluate the degree of homogeneity of 1, 5, and 10% w/w KinetiSol^®-processed samples. Powder blend homogeneity and content uniformity were evaluated, and all samples demonstrated a meloxicam concentration % relative standard deviation of ≤2.0%. SEM/EDS was utilized to map elemental distribution of the processed samples, which confirmed KinetiSol^®-processed materials were homogeneous at a 25 µm² area. Utilizing Raman spectroscopy, we were able to verify the amorphous content of the processed samples. Finally, we utilized ssNMR ^1?H spin-lattice relaxation measurement to evaluate the molecular miscibility of meloxicam with the polymer at 1% w/w drug load, for the first time, and determined the processed sample was highly miscible at ～200?nm scale. In conclusion, we determined the KinetiSol^® process is capable of producing ASDs that are homogeneously and molecularly well-dispersed drug-in-polymer at drug concentrations as low as 1% w/w.     

Effects of NaCl,SO2, NH3, O3, and ultraviolet light on atmospheric corrosion of Zn

The atmospheric corrosion behavior of Zn was studied in laboratory environments containing constituents that have not previously received much attention, in particular, humidity, SO₂, NH ₃, and O ₃, along with ultraviolet (UV) light irradiation and a preloading of NaCl. After exposure, corrosion rates were measured using mass loss, and corrosion products were identified by X-ray diffraction, Fourier transform-infrared spectroscopy, and energy dispersive spectroscopy. In this study, UV light and O ₃ did not significantly affect the Zn corrosion rate in the absence of Cl ⁻. However, when NaCl was present, UV light inhibited the Zn corrosion rate below 90% relative humidity (RH) and accelerated the Zn corrosion rate at 99% RH. The presence of UV light also increased the formation of zinc hydroxyl sulfate and gordaite when exposed to 120 parts per billion (ppb) SO ₂ and NaCl. The combination of SO ₂ and O ₃ with the preloading of NaCl increased the corrosion rate of Zn compared with NaCl alone. NH ₃ at a concentration of 550 ppb did not have a significant effect on the Zn corrosion rate.