The goal of this research is to better understand the role of miscibility, molecular interactions and mobility on the physical stability of amorphous solid dispersions. Previous research has suggested that the formation of an intimately mixed drug-polymer mixture contributes to the stabilization of the amorphous drug compound. In order to increase the physical stability, the amorphous drug is often formulated with a suitable polymer to form an amorphous solid dispersion. However, an amorphous drug substance is inherently unstable because it is a high energy form. The amorphous formulation is one of the promising techniques to increase the oral bioavailability of these poorly water-soluble compounds. This has led to insufficient oral bioavailability of many compounds in vitro. Many pharmaceutical compounds being developed in recent years are poorly soluble in water. Results prove the proposed unipolar time-differential property and show that time resolution in non- dispersive amorphous solids can be improved substantially to reach the theoretical limit set by spatial spreading of the collected Gaussian carrier cloud.Ī Molecular-Level View of the Physical Stability of Amorphous Solid Dispersions The fabricated devices are characterized with optical, x-ray, and gamma-ray impulse-like excitations. For the first time, we have fabricated a true Frisch grid inside a solid-state detector by evaporating amorphous selenium over photolithographically prepared multi-well substrates. To circumvent the problem of poor charge transport in amorphous solids, we propose unipolar time-differential charge sensing by establishing a strong near-field effect using an electrostatic shield within the material. However, amorphous solids have been ruled out as viable radiation detection media for high frame-rate applications, such as single-photon-counting imaging, because of low carrier mobilities, transit-time-limited photoresponse, and consequently, poor time resolution. The use of high resistivity amorphous solids as photodetectors, especially amorphous selenium, is currently of great interest because they are readily produced over large area at substantially lower cost compared to grown crystalline solids. International Nuclear Information System (INIS) Unipolar time-differential charge sensing in non- dispersive amorphous solids ![]() In comparison, the amorphous solid dispersion proved to be more stable with increased aqueous solubility. Exposure of amorphous zopiclone to moisture results in rapid transformation of the amorphous form to the crystalline dihydrated form. The zopiclone amorphous solid-state form was determined to be a fragile glass it was concluded that the stability of the amorphous form is influenced by both temperature and water. The physico-chemical properties and stability of amorphous zopiclone and the solid dispersion was studied using differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), hot-stage microscopy (HSM), X-ray diffractometry (XRD), solubility, and dissolution studies. The solid dispersion was prepared by a solvent evaporation method of zopiclone, polyvinylpyrrolidone-25 (PVP-25), and methanol, followed by freeze-drying. The amorphous form was prepared by the well-known method of quench-cooling of the melt. The aim of this study was to prepare and characterize an amorphous form of zopiclone as well as the characterization and performance of a stable amorphous solid dispersion. Zopiclone is a poorly soluble psychotherapeutic agent. ![]() ![]() Milne, Marnus Liebenberg, Wilna Aucamp, Marique The Stabilization of Amorphous Zopiclone in an Amorphous Solid Dispersion.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |