Background: Repackaging tablets into a dose administration aid (DAA) requires that the pharmacist consider the stability of the active pharmaceutical ingredient and the excipients of the drug product. Frusemide is susceptible to photodegradation and is commonly repackaged into DAAs. Aim: To evaluate the stability (chemical and physical) of frusemide tablets repackaged into DAAs. Method: Frusemide tablets repackaged into DAAs were evaluated for physicochemical stability over a period of 8 weeks at a controlled room temperature (25 ±2 ºC) and other relevant in-use conditions. In addition, photostability studies were performed according to the International Committee on Harmonisation (ICH) guidelines. Results: Chemical stability was confirmed for all storage conditions, including the ICH light conditions, with the frusemide content within the British Pharmacopoeial range of 95 to 105%. Although the physical stability was confirmed by all tests (weight uniformity, hardness, friability, disintegration, dissolution), storage in a simulated pharmacy environment after one week and exposure to ICH light conditions resulted in a yellow colouration of the tablets. Conclusion: Although the chemical and physical stability of frusemide was within acceptable limits during the study, the discolouration of the tablets from light exposure is unacceptable. It is recommended that DAAs are stored protected from light immediately after repackaging with frusemide tablets, and that patients are counselled to store the DAA in a cool dark place. J Pharm Pract Res 2007; 37: 178-81.
An experimental study was conducted to investigate the effect of the bevel angle on the radiated noise and the associated flow-field over the trailing-edge. The bevel angle of the trailing-edge was adjusted over a broad range of angles to demonstrate the aeroacoustic properties of the attached and separated boundary layers. The far-field noise results obtained from the beamforming array were assessed in conjunction with the associated flow-field. Far-field measurement results show an increased level of radiated noise for a range of bevel angles where the flow remains attached compared to the baseline flat-plate case without a bevel angle. Near-field measurements are presented in terms of pressure coefficients, unsteady surface pressure results, turbulence properties of the boundary layer, and corresponding spectral properties of these quantities. The near-field measurement results indicate that introducing a bevel angle yields a region of favorable pressure gradient on the flat-plate and bevel, which accelerates the flow and reduces the size of structures in the boundary layer up until the mid-bevel region, which then decelerates toward the trailing-edge. This change increases the energy content of surface pressure fluctuations as well as the energy content of the velocity field over the trailing-edge and wake, which, in turn, results in an increased radiated far-field noise as supported by beamforming results. Furthermore, at a sufficiently high bevel angle, where pronounced flow separation occurs, the lack of interaction between trailing-edge and shear layer leads to a significant reduction in the radiated far-field noise compared to that of the baseline flat-plate.
This paper provides an insight into the grid generated turbulence for aeroacoustic studies. Several passive grids of square bars were tested in the open-jet aeroacoustic facility at the University of Bristol. The geometric properties of the grids and their position within the tunnel contraction nozzle were varied to quantify their influence on the average and statistical flow properties, as well as the generated self-noise. Moreover, case studies involving turbulence interaction noise generation with a NACA0012 airfoil and cylinder were conducted. Turbulence intensity, integral length scale, and the anisotropy of the flow generated by each grid were characterized by hot-wire measurements, and the associated far-field noise was measured by a
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